Aiman Saad Nasr El-Din El-Khatib

We have addressed in the current study the potential of L-carnitine (LC) to extenuate the reproductive toxic insults of carbendazim (CBZ) in male rats, and the molecular mechanisms whereby carnitine would modify the spermatogenic and steroidogenic derangements invoked by the endocrine disruptor. Herein, animals received daily doses of carbendazim (100 mg/kg) by gavage for 8 weeks. Another CBZ-challenged group was co-supplemented with LC (500 mg/kg, IP) twice weekly for 8 weeks. Sperm quantity and quality (morphology, motility and viability), serum testosterone and gonadotropins, and thyroid hormone levels were assessed. Serum tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) concentrations were determined by ELISA. Oxidant/antioxidant status in rat testis was investigated via measuring testicular contents of malondialdehyde (MDA) and reduced glutathione (GSH), as well as the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Immunohistochemical localizations of the junctional protein; occludin, and inflammatory markers; inducible nitric oxide synthase (iNOS) and nuclear factor kappa beta (NF-κB) were further analyzed. A host of transduction genes that regulate spermatogenic and steroidogenic pathways, and their encoded proteins namely, Steroidogenic Acute Regulatory Protein (StAR), Fatty acid binding protein 9 (FABP9) and P38-mitogen activated protein kinase (P38-MAPK) were assessed by real time quantitative (RT-qPCR) and Western blot. LC improved rat spermiogram, testicular histological alterations and endocrine perturbances, and modulated genes' expressions and their respective proteins. In conclusion, LC effects appear to reside for the most part on its endocrine-preserving, anti-oxidant and anti-inflammatory properties through a myriad of interlaced signal transductions that ultimately recapitulated its beneficial effects on spermatogenesis and steroidogenesis.

Pregabalin (PRG) possesses great therapeutic benefits in the treatment of epilepsy, neuropathic pain, and fibromyalgia. However, clinical data have reported incidence or exacerbation of heart failure following PRG administration. Experimental data exploring cardiac alterations and its underlying mechanisms are quite scarce. The aim of the present work was to investigate the effect of PRG on morphometric, echocardiographic, neurohumoral, and histopathological parameters in rats. It was hypothesized that alterations in cardiac renin angiotensin system (RAS) might be involved in PRG-induced cardiotoxicity. To further emphasize the role of RAS in the mechanism of PRG-induced cardiotoxicity, the protective potential of diminazene aceturate (DIZE), an ACE2 activator, was investigated. Results showed 44% decrease in ejection fraction and sevenfold increase in plasma N-terminal pro-brain natriuretic peptide. Histopathological examination also showed prominent vacuolar changes and edema in cardiomyocytes. In addition, PRG significantly increased angiotensin II (Ang II), angiotensin converting enzyme (ACE) and angiotensin II type 1 receptor (AT1R) levels, while decreased angiotensin 1-7 (Ang 1-7), angiotensin converting enzyme 2 (ACE2), and Mas receptor (MasR) cardiac levels. DIZE co-administration showed prominent protection against PRG-induced echocardiographic, neurohumoral, and histopathological alterations in rats. In addition, downregulation of ACE/Ang II/AT1R and upregulation of ACE2/Ang 1-7/MasR axes were noted in DIZE co-treated rats. These findings showed, for the first time, the detailed cardiac deleterious effects of PRG in rats. The underlying pathophysiological mechanism is probably mediated via altered balance between the RAS axes in favor to the ACE/Ang II/AT1R pathway. Accordingly, ACE2 activators might represent promising therapeutic agents for PRG-induced cardiotoxicity.

BACKGROUND: Acute myocardial infarction (AMI) remains the most common cause of morbidity and mortality worldwide. The present study was directed to investigate the beneficial effects of benfotiamine pre- and post-treatments in isoproterenol (ISO)-induced MI in rats.

METHODS: Myocardial heart damage was induced by subcutaneous injection of ISO (150 mg/kg) once daily for two consecutive days. Benfotiamine (100 mg/kg/day) was given orally for two weeks before or after ISO treatment.

RESULTS: ISO administration revealed significant changes in electrocardiographic recordings, elevation of levels of cardiac enzymes; creatinine kinase (CK-MB) and troponin-I (cTn-I), and perturbation of markers of oxidative stress; nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and glutathione peroxidase (GPx) and markers of inflammation; protein kinase C (PKC), nuclear factor-kappa B (NF-κB) and metalloproteinase-9 (MMP-9). The apoptotic markers (caspase-8 and p53) were also significantly elevated in ISO groups in addition to histological alterations. Groups treated with benfotiamine pre- and post-ISO administration showed significantly decreased cardiac enzymes levels and improved oxidative stress, inflammatory and apoptotic markers compared to the ISO groups.

CONCLUSION: The current study highlights the potential role of benfotiamine as a promising agent for prophylactic and therapeutic interventions in myocardial damage in several cardiovascular disorders via NADPH oxidase inhibition.

Myopathy is a well-known adverse effect of statins, affecting a large sector of statins users. The reported experimental data emphasized on mechanistic study of statin myopathy on large muscles. Clinically, both large muscles and respiratory muscles are reported to be involved in the myotoxic profile of statins. However, the experimental data investigating the myopathic mechanism on respiratory muscles are still lacking. The present work aimed to study the effect of atorvastatin treatment on respiratory muscles using rat isolated hemidiaphragm in normoxic & hypoxic conditions. The contractile activity of isolated hemidiaphragm in rats treated with atorvastatin for 21 days was investigated using nerve stimulated technique. Muscle twitches, train of four and tetanic stimulation was measured in normoxic, hypoxic and reoxygenation conditions. Atorvastatin significantly increased the tetanic fade, a measure of muscle fatigability, in hypoxic conditions. Upon reoxygenation, rat hemidiaphragm regains its normal contractile profile. Co-treatment with coenzyme Q10 showed significant improvement in defective diaphragmatic contractility in hypoxic conditions. This work showed that atorvastatin treatment rapidly deteriorates diaphragmatic activity in low oxygen environment. The mitochondrial respiratory dysfunction is probably the mechanism behind such finding. This was supported by the improvement of muscle contractile activity following CoQ10 co-treatment.

Myopathy is a well-known adverse effect of statins, affecting a large sector of statins users. The reported experimental data emphasized on mechanistic study of statin myopathy on large muscles. Clinically, both large muscles and respiratory muscles are reported to be involved in the myotoxic profile of statins. However, the experimental data investigating the myopathic mechanism on respiratory muscles are still lacking. The present work aimed to study the effect of atorvastatin treatment on respiratory muscles using rat isolated hemidiaphragm in normoxic & hypoxic conditions. The contractile activity of isolated hemidiaphragm in rats treated with atorvastatin for 21 days was investigated using nerve stimulated technique. Muscle twitches, train of four and tetanic stimulation was measured in normoxic, hypoxic and reoxygenation conditions. Atorvastatin significantly increased the tetanic fade, a measure of muscle fatigability, in hypoxic conditions. Upon reoxygenation, rat hemidiaphragm regains its normal contractile profile. Co-treatment with coenzyme Q10 showed significant improvement in defective diaphragmatic contractility in hypoxic conditions. This work showed that atorvastatin treatment rapidly deteriorates diaphragmatic activity in low oxygen environment. The mitochondrial respiratory dysfunction is probably the mechanism behind such finding. This was supported by the improvement of muscle contractile activity following CoQ10 co-treatment.

Pregabalin (PRG) is highly effective in the treatment of epilepsy, neuropathic pain and anxiety disorders. Despite its potential benefits, PRG administration has been reported to induce or exacerbate heart failure (HF). It has been previously documented that overactivation of the renin angiotensin system (RAS) is involved in HF pathophysiological mechanism. The target of the current study was to examine the possible cardioprotective effect of telmisartan (Tel), an angiotensin II type 1 receptor (AT1R) blocker, compared with that of captopril (Cap), an angiotensin converting enzyme (ACE) inhibitor, in ameliorating PRG-induced HF in rats by assessing morphometric, echocardiographic and histopathological parameters. Furthermore, to investigate the role of RAS blockade by the two drugs in guarding against PRG-induced changes in cardiac angiotensin 1-7 (Ang 1-7) and angiotensin II (Ang II) levels, in addition to myocardial expression of ACE2, ACE, Mas receptor (MasR) and AT1R. Results showed that PRG administration induced morphometric, echocardiographic and histopathological deleterious alterations and significantly elevated cardiac Ang II, ACE and AT1R levels, while reduced Ang 1-7, ACE2 and MasR cardiac levels. Concurrent treatment with either Tel or Cap reversed PRG-induced morphometric, echocardiographic and histopathological abnormalities and revealed prominent protection against PRG-induced HF via downregulation of ACE/Ang II/AT1R and upregulation of ACE2/Ang 1-7/MasR axes. These are the first findings to demonstrate that the potential benefits of Tel and Cap are mediated by counteracting the altered balance between the RAS axes induced by PRG. Hence; Tel and Cap may attenuate PRG-induced HF partially through stimulation of ACE2/Ang 1-7/MasR pathway.

Statins like simvastatin (SIM) have demonstrated to have pleiotropic actions other than their conventional use as antilipidemic drugs. Also, nowadays natural scaffolds like platelets rich fibrin (PRF) showed promising results on bone regeneration. Aim This study compare the regenerative power of SIM and PRF added locally each as a sole filling material on induced bone defect and evaluate the combined effect using PRF loaded with SIM. MATERIALS AND METHODS: A critical size bone defect was induced in 48 male albino rats of average weight 150-200 g and were divided into 4 groups according to the filling material. Control, PRF, SIM, and SIM/PRF group. Each group was subdivided according to the sacrificing period into two subgroups (one and two-months postoperatively). Tibial specimens were evaluated histologically using masson trichrome (MT) special stain to detect areas of new bone formation, immunohistochemically using anti- BMP2 and anti-VEGF, serum levels of Osteoprotegerin (OPG), RANKL, osteocalcin and alkaline phosphatase enzyme (ALP) were measured one and two months postoperatively using ELISA, Finally bone mineral density (BMD) at the bone defect area was analyzed using digital X-ray one and two-months postoperatively. RESULTS: The percentage of newly formed bone increased significantly in the three groups vs the control group with the highest significant increase (p < 0.001) in the SIM/PRF group one month postoperatively. Also, SIM/PRF group was the only group which showed significant bone maturation two-months postoperatively compared to the other groups. Immunohistochemical analysis showed significant increase in positively stained BMP-2 and VEGF expression (p < 0.001) in the three groups vs the control group with the highest significant increase (p < 0.001) in the SIM/PRF group. Serum bone anabolic markers increased significantly in the SIM and SIM/PRF groups. In contrast, RANKL serum level decreased significantly in the SIM and SIM/PRF group one month postoperatively with no significant decrease in the PRF group vs the control group. Digital X-ray results revealed the highest BMD percent change was found in the SIM/PRF group and showed complete bone healing two-months postoperatively.

Myopathy is the most commonly reported adverse effect of statins. All statins are associated with myopathy, though with different rates. Rosuvastatin is a potent statin reported to induce myopathy comparable to earlier statins. However, in clinical practice most patients could tolerate rosuvastatin over other statins. This study aimed to evaluate the myopathic pattern of rosuvastatin in rats using biochemical, functional and histopathological examinations. The possible deleterious effects of rosuvastatin on muscle mitochondria were also examined. The obtained results were compared to myopathy induced by atorvastatin in equimolar dose. Results showed that rosuvastatin induced a rise in CK, a slight increase in myoglobin level together with mild muscle necrosis. Motor activity, assessed by rotarod, showed that rosuvastatin decreased rats' performance. All these manifestations were obviously mild compared to the prominent effects of atorvastatin. Parallel results were obtained in mitochondrial dysfunction parameters. Rosuvastatin only induced a slight increase in LDH and a minor decrease in ATP (∼14%) and pAkt (∼12%). On the other hand, atorvastatin induced an increase in LDH, lactate/pyruvate ratio and a pronounced decline in ATP (∼80%) and pAkt (∼65%). These findings showed that rosuvastatin was associated with mild myotoxic effects in rats, especially when compared to atorvastatin.

Myopathy is among the well documented and the most disturbing adverse effects of statins. The underlying mechanism is still unknown. Mitochondrial dysfunction related to coenzyme Q10 decline is one of the proposed theories. The present study aimed to investigate the mechanism of atorvastatin-induced myopathy in rats. In addition, the mechanism of the coenzyme Q10 protection was investigated with special focus of mitochondrial alterations. Sprague-Dawely rats were treated orally either with atorvastatin (100mg/kg) or atorvastatin and coenzyme Q10 (100mg/kg). Myopathy was assessed by measuring serum creatine kinase (CK) and myoglobin levels together with examination of necrosis in type IIB fiber muscles. Mitochondrial dysfunction was evaluated by measuring muscle lactate/pyruvate ratio, ATP level, pAkt as well as mitochondrial ultrastructure examination. Atorvastatin treatment resulted in a rise in both CK (2X) and myoglobin (6X) level with graded degrees of muscle necrosis. Biochemical determinations showed prominent increase in lactate/pyruvate ratio and a decline in both ATP (>80%) and pAkt (>50%) levels. Ultrastructure examination showed mitochondrial swelling with disrupted organelle membrane. Co-treatment with coenzyme Q10 induced reduction in muscle necrosis as well as in CK and myoglobin levels. In addition, coenzyme Q10 improved all mitochondrial dysfunction parameters including mitochondrial swelling and disruption. These results presented a model for atorvastatin-induced myopathy in rats and proved that mitochondrial dysfunction is the main contributor in statin-myopathy pathophysiology.

Liver fibrosis is one of the most serious consequences of S. mansoni infection. The aim of the present study was to investigate the potential anti-fibrotic effect of human Wharton's jelly-derived mesenchymal stem cells (WJMSCs) combined with praziquantel (PZQ) in S. mansoni-infected mice. S. mansoni-infected mice received early (8(th) week post infection) and late (16(th) week post infection) treatment with WJMSCs, alone and combined with oral PZQ. At the 10(th) month post infection, livers were collected for subsequent flow cytometric, histopathological, morphometric, immunohistochemical, gene expression, and gelatin zymographic studies. After transplantation, WJMSCs differentiated into functioning liver-like cells as evidenced by their ability to express human hepatocyte-specific markers. Regression of S. mansoni-induced liver fibrosis was also observed in transplanted groups, as evidenced by histopathological, morphometric, and gelatin zymographic results besides decreased expression of three essential contributors to liver fibrosis in this particular model; alpha smooth muscle actin, collagen-I, and interleukin-13. PZQ additionally enhanced the beneficial effects observed in WJMSCs-treated groups. Our results suggest that combining WJMSCs to PZQ caused better enhancement in S. mansoni-induced liver fibrosis, compared to using each alone.

This study aimed to investigate the anti-depressant effect of hesperidin (Hsp) in streptozotocin (STZ)-induced diabetic rats. Additionally, the effect of Hsp on hyperglycaemia, oxidative stress, inflammation, brain-derived neurotrophic factor (BDNF), and brain monoamines in diabetic rats was also assessed. The Wistar rats in the experimental groups were rendered hyperglycaemic with a single dose of STZ (52.5 mg·(kg body mass)(-1), by intraperitoneal injection). The normal group received the vehicle only. Hyperglycaemic rats were treated with Hsp (25.0, 50.0, or 100.0 mg·(kg body mass)(-1)·day(-1), per oral) and fluoxetine (Flu) (5.0 mg·(kg body mass)(-1)·day(-1), per oral) 48 h after the STZ injection, for 21 consecutive days. The normal and STZ control groups received the vehicle (distilled water). Behavioral and biochemical parameters were then assessed. When Hsp was administered to the STZ-treated rats, this reversed the STZ-induced increase in immobility duration in the forced swimming test (FST) and attenuated hyperglycaemia, decreased malondialdehyde (MDA), increased reduced glutathione (GSH) decreased interleukin-6 (IL-6), and increased BDNF levels in the brain. Treatment with Hsp attenuated STZ-induced neurochemical alterations, as indicated by increased levels of monoamines in the brain, namely, norepinephrine (NE), dopamine (DA), and serotonin (5-hydroxytryptamine; 5-HT). All of these effects of Hsp were similar to those observed with the established anti-depressant Flu. This study shows that Hsp exerted anti-depressant effect in diabetic rats, which may have been partly mediated by its amelioration of hyperglycaemia as well as its anti-oxidant and anti-inflammatory activities, the enhancement of neurogenesis, and changes in the levels of monoamines in the brain.

BACKGROUND: Hepatic schistosomiasis is considered to be one of the most prevalent forms of chronic liver disease in the world due to its complication of liver fibrosis. The demonstration of the pro-fibrogenic role of angiotensin (Ang) II in chronic liver disease brought up the idea that anti-Ang II agents may be effective in improving hepatic fibrosis by either blocking Ang II type 1 (AT1) receptors or inhibiting the angiotensin converting enzyme. Peroxisome proliferator-activated receptors gamma (PPARγ) activation has been also shown to inhibit hepatic stellate cell activation and progression of fibrosis. The present study has aimed at testing the anti-fibrogenic effects of telmisartan; an AT1 receptor blocker and a PPARγ partial agonist, alone or combined with praziquantel (PZQ) on Schistosoma mansoni-induced liver fibrosis in mice.

METHODS: To achieve the aim of the study, two sets of experiments were performed in which telmisartan was initiated at the 5th (set 1) and the 10th (set 2) weeks post infection to assess drug efficacy in both acute and chronic stages of liver fibrosis, respectively. Schistosoma mansoni-infected mice were randomly divided into the following four groups: infected-control (I), telmisartan-treated (II), PZQ-treated (III), and telmisartan+PZQ-treated (IV). In addition, a normal non-infected group was used for comparison. Parasitological (hepatomesenteric worm load and oogram pattern), histopathological, morphometric, immunohistochemical (hepatic expressions of matrix metalloproteinase-2; MMP-2 and tissue inhibitor of metalloproteinase-2; TIMP-2), and biochemical (serum transforming growth factor beta 1; TGF-β1 and liver function tests) studies were performed.

RESULTS: Telmisartan failed to improve the parasitological parameters, while it significantly (P<0.05) decreased the mean granuloma diameter, area of fibrosis, and serum TGF-β1. Additionally, telmisartan increased MMP-2 and decreased TIMP-2 hepatic expression. Combined treatment failed to show any additive properties, yet it did not affect the anti-schistosomal activity of PZQ.

CONCLUSIONS: These results suggest potential anti-fibrotic effects of telmisartan, an AT1 receptor blocker and a PPARγ partial agonist, in acute and chronic stages of Schistosoma mansoni-induced liver fibrosis in mice.

Solanum indicum ssp. distichum is used as a vegetable in some parts of Africa and claimed in folk medicine to guard against cardiovascular disorders. It was of interest to study the potential blood pressure lowering effects of a standardized extract of the fruit. An ethanolic extract of the fruit, standardized to contain > 0.15% chlorogenic acids, was tested orally in both normotensive rats and in those rendered hypertensive by twice daily intraperitoneal injection of N(W)-nitro-L-arginine methylester (L-NAME) for 1 week. The extract was either given at the same time as l-NAME or after the establishment of hypertension. The systolic blood pressure (SBP) was measured non-invasively using a tail cuff computer-aided monitoring device. Treatment of normotensive rats with the extract (30-300 mg/kg) for 4 weeks showed no hypotensive effect. Giving the extract (100 and 300 mg/kg) orally once daily during the 1 week hypertension induction period with L-NAME prevented the development of hypertension. Administration of the extract orally for 1 week after the establishment of hypertension tended to normalize the blood pressure. Pharmacological evidence for the antihypertensive activity of S. distichum is hereby reported for the first time. The extract showed good prophylactic as well as curative effect against L-NAME-induced hypertension, whereby its content of chlorogenic acids may play a minor role. Other constituents may be responsible for the antihypertensive action. The findings support further development of the extract as a potential therapeutically useful antihypertensive agent.

Propolis has been extensively used in folk medicine for the management of a wide spectrum of disorders. In a previous study, we demonstrated the protective effect of the aqueous propolis extract (APE) against the injurious effects of carbon tetrachloride (CCl4) on hepatocytes in vitro. The present investigation was carried out to show whether the hepatoprotective effect of the extract could also be manifested in vivo. Rats were given APE orally for 14 consecutive days, before being subjected to a single intraperitoneal injection of CCl4. One day after the CCl4 injection, the animals were sacrificed, hepatocytes were isolated and liver homogenates were prepared for the assessment of liver injury. In isolated hepatocytes, APE afforded protection against CCl4-induced injury as manifested by a decrease in the leakage of the cytosolic enzyme lactate dehydrogenase (LDH), decreased generation of lipid peroxide and maintenance of cellular reduced glutathione (GSH) content. In principle, similar findings were observed in liver homogenates. The present findings show that APE has in vivo hepatoprotective potential which could be attributed at least in part to the maintenance of cellular GSH content. The latter effect seems to play an important role in conserving the integrity of biomembranes as it was associated with a decrease in lipid peroxidation and reduced leakage of cytosolic LDH.

The present investigation focused, firstly, on the effects of oral administration of thymoquinone (TQ) on antioxidant enzyme activities, lipid peroxidation and DT-diaphorase activity in hepatic, cardiac and kidney tissues of normal mice. Superoxide dismutase (SOD; E.C:1.15.1.1), catalase (CAT; E.C:1.11.1.6), glutathione peroxidase (GSH-Px; E.C:1.11.1.9), glutathione-S-transferase (GST; E.C:2.5.1.18), and DT-diaphorase (E.C:1.6.99.2) enzyme activities in each tissue type were determined. Treatment of mice with the different doses of TQ (25, 50 and 100 mg kg(-1) day(-1) orally) for 5 successive days, produced significant reductions in hepatic SOD, CAT and GSH-Px activities. In addition cardiac SOD activity was markedly inhibited with the higher doses of TQ, (namely 50 and 100 mg kg(-1)). Moreover, TQ (100 mg kg(-1)) significantly reduced hepatic and cardiac lipid peroxidation as compared with the respective control group. Conversely, TQ (50,100 mg kg(-1)) and TQ (100 mg kg(-1)) enhanced cardiac and renal DT-diaphorase activity respectively. However, the selected doses of TQ neither produced any change in GST activity nor influenced reduced glutathione content in all tissues studied. TQ was tested, secondly, as a substrate for hepatic, cardiac and renal DT-diaphorase of normal mice in the presence of NADPH. Kinetic parameters for the reduction of TQ to dihydrothymoquinone (DHTQ) indicated that DT-diaphorase of different tissues can efficiently reduce TQ to DHTQ. K(m) and V(max) values revealed that hepatic DT-diaphorase exhibited the higher values, while the lower values were associated with renal DT-diaphorase. TQ and DHTQ were tested, thirdly, as specific scavengers for superoxide anion (generated biochemically) or as general scavengers for free radicals (generated photochemically). The results revealed that TQ and DHTQ acted not only as superoxide anion scavengers but also as general free radical scavengers. The IC(50) for TQ and DHTQ in biochemical and photochemical assays were in the nanomolar and micromolar range respectively. Our data may explain at least partly the reported beneficial in vivo protective effects of TQ through the combined antioxidant properties of TQ and its metabolite DHTQ.

The effect of Ginkgo biloba extract (EGb 761) on bleomycin (BLM)-induced acute lung injury was studied in rats. The responsiveness of isolated pulmonary arterial rings to 5-hydroxytryptamine (5-HT) as well as the levels of some relevant biochemical markers in the lung tissue were taken as evidence for the acute lung injury. BLM was given intraperitoneally at a dose of 15 mg/kg/day for five consecutive days. It was found that BLM treatment attenuated the vasoconstrictor effect of 5-HT on the isolated pulmonary arteries. In lung tissues BLM also elevated the level of lipid peroxides and enhanced the activity of glutathione peroxidase. On the other hand, the level of glutathione and the activity of alkaline phosphatase were reduced. Body weight, lung weight and tissue glutathione-S-transferase activity were, however, not altered. Oral administration of EGb 761 at a dose of 100 mg/kg/day for five consecutive days did not alter any of the chosen biochemical parameters in the lung tissue except for a slight reduction in alkaline phosphatase activity. However, treatment with EGb 761 reduced the responsiveness of the pulmonary artery to 5-HT. Administration of EGb 761 (100 mg/kg/day; po) two hours prior to BLM (15 mg/kg/day; ip), for five consecutive days blunted the occurrence of further reduction in the vasoconstrictor response of the pulmonary artery to 5-HT. Furthermore, EGb 761 tended to normalize BLM-induced alterations in the measured biochemical markers in the lung tissue. The apparent modulatory influence of EGb 761 on BLM-induced acute lung injury stems, at least in part, from its beneficial free radical scavenging properties that provide the extract with antioxidant activity.

The effects of aminoguanidine (AG; 100 mg x kg(-1)) and desferrioxamine (DFO; 50 mg x kg(-1)) on some vascular and biochemical changes associated with streptozotocin (STZ; 65 mg x kg(-1); i.p.)-induced hyperglycaemia were investigated in rats. Both AG and DFO were administered i.p., once daily, for 14 consecutive days to normal and hyperglycaemic animals. The responsiveness of the isolated aortic rings to phenylephrine (PE) was tested. In addition, biochemical markers for oxidative stress such as plasma levels of lipid peroxides and total thiols, as well as the activities of erythrocytic superoxide dismutase (SOD) and whole blood glutathione peroxidase (GSH-Px) were assessed. Results of the present study indicated that induction of hyperglycaemia was associated with increased aortic ring responsiveness to PE, loss in body weight, increase in urine volume, elevation of plasma total thiols and lipid peroxide levels and elevated SOD and GSH-Px enzymatic activities. Treatment of normal rats with AG reduced the response of their aortae to PE. Furthermore, a profound increase in body weight without any significant change in the measured biochemical parameters was observed. In hyperglycaemic animals, AG tended to normalize the enhanced aortic response to PE and modulated STZ-induced biochemical changes without affecting the elevated plasma glucose level. Treatment of normal rats with DFO reduced the response of their aortae to PE and decreased their body weight without altering any of the chosen biochemical parameters. In hyperglycaemic animals, DFO attenuated the responsiveness of their aortae to PE and at the same time, did not affect the loss in body weight and the elevation of plasma glucose level observed in the hyperglycaemic group. Additionally, DFO normalized the elevated plasma level of total thiols and exerted a modulatory influence on the enhanced activities of SOD and GSH-Px as well as on the increased levels of lipid peroxides. Our data lend further credence for the contribution of oxidative stress in the vascular and biochemical changes associated with STZ-induced hyperglycaemia. It is also apparent that advanced glycosylation end products and nitric oxide might be involved. Until clinical studies prove the efficacy and safety of these drugs, specific agents which could scavenge free radicals and block protein glycosylation seem beneficial as a helpful adjunct to the therapy of diabetes.

Effects of the volatile oil constituents of Nigella sativa, namely, thymoquinone (TQ), p-cymene and alpha-pinene, on carbon tetrachloride (CCl4-indued acute liver injury were investigated in mice. A single dose of CCl4 (15 microl/Kg i.p.) induced hepatotoxicity 24 h after administration manifested biochemically as significant elevation of the enzymes activities of serum alanine transaminase (ALT, EC:2.6.1.2), asparate transaminase (AST, EC:2.6.1.1) and lactate dehydrogenase (LDH, EC: 1.1.1.27). The toxicity was further evidenced by a significant decrease of non-protein sulfhydryl(-SH) concentration, and a significant increase of lipid peroxidation measued as malondialdhyde (MDA) in the liver tissues. Administration of different doses of the TQ (4, 8, 12.5, 25 and 50 mg/Kg i.p.) did not alter the chosen biochemical parameters measured, while higher doses of TQ were lethal. The LD50 was 90.3 mg/Kg (77.9-104.7, 95% CL). Pretreatment of mice with different doses of TQ 1 h before CCl4 injection showed that the only dose of TQ that ameliorated hepatotoxicity of CCl4 was 12.5 mg/Kg i.p. as evidenced by the significant reduction of the elevated levels of serum enzymes as well as hepatic MDA content and significant increase of the hepatic nonprotein sulfhydryl(-SH) concentration. Treatment of mice with the other volatile oil constituents, p-cymene or alpha-pinene did not induce any changes in the serum ALT measured. In addition, i.p. administration of these compounds 1 h before CCl4 injection, did not protect mice against CC4-induced hepatotoxicity. The results of the present study indicate that TQ (12.5 mg/Kg, i.p.) may play an important role as antioxidant and may efficiently act as a protective agent against chemically-induced hepatic damage. In contrast, higher doses of TQ were found to induce oxidative stress leading to hepatic injury.

Meloxicam is a new non-steroidal anti-inflammatory drug, that possesses a selective inhibition of the inducible isoform of cyclooxygenase enzyme (COX-2) relative to the constitutive one, COX-1. Oxidative stress has been documented to be involved in the aetiology of many pathological conditions. The present study aims to further explore the relationship between free radical generation and the inflammatory process, and extends more to investigate the effect of meloxicam on the oxidant status in experimentally induced arthritis, namely, Freund's adjuvant-induced arthritis in rats. Results of the present investigation revealed that animals inoculated with Freund's complete adjuvant showed a biphasic response regarding changes in the right hind paw oedema volume. During the chronic phase of the disease, arthritic animals showed an elevated plasma level of lipid peroxides, enhanced blood glutathione peroxidase activity, with depletion of plasma total thiols and albumin; while no significant effects have been observed on erythrocytic superoxide dismutase activity and plasma total proteins content, as compared to normal untreated rats. Long-term administration of meloxicam, at two dose levels, produced significant antioedemetous effect and succeeded in modulating the altered parameters affected during arthritis. The selected dose regimens of meloxicam did not show any apparent lesions in the gastric mucosa. The results of the present investigation lend further support to the reported observations concerning selective COX-2 inhibitors. The modulatory influence of meloxicam on the oxidant status, particularly on lipid peroxidation and thiols might be a relevant effect accounting for its anti-inflammatory properties.