Hany Arab

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Cadmium is an extremely toxic pollutant that reaches human body through intake of the industrially polluted food and water as well as through cigarette smoking and exposure to polluted air. Cadmium accumulates in different body organs especially the liver. It induces tissue injury largely through inflammation and oxidative stress-based mechanisms. The aim of the current study was to investigate the ability of γ glutamyl cysteine (γGC) to protect against cadmium-induced hepatocellular injury employing Wistar rats as a mammalian model. The results of the current work indicated that γGC upregulated the level of the anti-inflammatory cytokine IL-10 and downregulated the levels of the pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in the cadmium-exposed rats. In addition, γGC reduced the liver tissues cadmium content in the cadmium-treated rats, suppressed the cadmium-induced hepatocellular apoptosis and oxidative modifications of cellular DNA, lipids, and proteins. Additionally, γGC enhanced the antioxidant potential of the liver tissues in the cadmium-treated rats as evidenced by a remarkable increase in the activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase and significant increase in the levels of the total antioxidant capacity and reduced glutathione as well as a significant reduction in oxidized to reduced glutathione (GSSG/GSH) ratio. Moreover, it effectively improved liver cell integrity in the cadmium-treated rats as demonstrated by a significant reduction in the serum activity of the liver enzymes (ALT and AST) and amelioration of the cadmium-evoked histopathological alterations. Together, these findings underscore, for the first time, the alleviating effects of γGC against cadmium-induced hepatocellular injury that is potentially mediated through reduction of liver tissue cadmium content along with modulation of both hepatocellular redox status and inflammatory cytokines.

Rheumatoid arthritis (RA) is a chronic inflammatory arthropathy that principally attacks the joints. The present study aimed to explore the potential anti-arthritic effects of caffeic acid and ellagic acid in adjuvant-induced arthritis, compared to celecoxib. The current study also explored the underlying molecular mechanisms e.g., pro-inflammatory signals including chitinase-3-like protein-1 (CHI3L1); a glycoprotein that correlates with RA joint destruction besides angiogenesis, oxidative stres and apoptosis. Interestingly, caffeic and ellagic acids attenuated the severity of arthritis with comparable efficacy to celecoxib. Both agents effectively mitigated paw edema and inflammatory cell infiltration and protected the joint tissues against pannus formation along with cartilage and bone destruction. Notably, they also lowered the paw expression of NF-κB and the downstream effector CHI3L1 and its synthesis inducer IL-1β. They also lowered the levels of the tissue remodeling factor MMP-9 and the angiogenic signal VEGF in rat paws. Both agents also suppressed serum oxidative stress via diminishing lipid peroxides and nitric oxide together with augmentation of reduced glutathione in arthritic animals. Regarding apoptosis, they attenuated paw caspase-3 levels, favoring cell survival. Together, these favorable findings may advocate the use of caffeic and ellagic acids as adjunct modalities for the management of RA to mitigate joint damage.

BACKGROUND AND PURPOSE: Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory disease which poses a need to explore effective yet safe pharmacotherapeutic options. The current work aimed to study the therapeutic role of nicorandil in controlling RA.

EXPERIMENTAL APPROACH: Complete Freund's adjuvant (CFA)-induced arthritis model was applied by injecting 400 μL of CFA in the right hind paw at day 0 and day 7. Four groups of rats were used as follows: normal-control (CTRL), CFA-induced arthritis (ART), CFA-induced arthritis treated with diclofenac (DIC) and CFA-induced arthritis treated with nicorandil (NIC). Both NIC and DIC were administered at day 14 for two weeks. Paw volume, knee joint diameter, pain behavior assessment as well as body weight were all periodically recorded throughout the experimental period. Following the sacrifice of animals at day 28, gene expressions of TLR-4, MyD88 and TRAF6 as well as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), nuclear factor Kappa B (NF-κB) were quantified in hind paws tissue. Finally, the serum levels of the inflammatory biomarkers (tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) together with the histopathological examination of sections in the rat hind paw were recorded.

RESULTS: Both NIC and DIC proved promising anti-arthritic potential mediated, at least in part through switching off TLR4-MyD88-TRAF6 axis as well as downstream TRAF6 dependent activated MAP kinases and NF-κB.

CONCLUSION AND IMPLICATIONS: Nicorandil, via interfering with TLR4 signaling, sheds light on a potential clinical role of the drug in pursuit for safe and effective regimens for RA.

Excessive drinking of alcohol has been frequently associated with gastric injury; however, its underlying molecular mechanisms have been inadequately investigated. Methyl palmitate (MP) has demonstrated marked hepato-, cardio- and pulmonary protective features; however, its effects on ethanol-induced gastric injury have not been studied. The aim of the present study was to evaluate the potential gastroprotective activity of MP against ethanol-evoked gastric mucosal damage in rats and associated molecular mechanisms, for example, mitogen-activated protein kinases (MAPKs), nuclear factor κB (NF-κB), and phosphoinositide 3 kinase/protein kinase B (PI3K/AKT) pathways. The rat stomachs were examined in terms of the inflammatory, oxidative, and apoptotic perturbations. Current data demonstrated that pretreatment with MP attenuated the gross gastric damage, scores of ulcer index, area of mucosal lesions and histopathology outcomes; actions which were similar to the reference antiulcer omeprazole. MP inhibited NF-κB expression, its nuclear translocation, and the expression of its downstream signals, for example, tumor necrosis factor-α and myeloperoxidase besides restoration of interleukin-10 levels. Western blot analysis revealed that MP counteracted the disruption of MAPKs signaling via lowering p-c-Jun N-terminal kinase 1/2 (p-JNK1/2) expression and restoring the phospho-extracellular signal-regulated kinase 1/2 (p-ERK1/2) levels without affecting p-p38MAPK levels. Additionally, MP improved the antioxidant milieu via diminishing lipid peroxides and enhancing glutathione, glutathione peroxidase, total antioxidant capacity and mucosal nitric oxide. In the context of apoptosis, MP inhibited the cleavage of caspase-3 and poly(ADP-ribose)polymerase (PARP) and Bax protein expression with upregulating B cell lymphoma-2 expression (Bcl-2), thus, promoting gastric cellular survival. This was confirmed by MP activation of the PI3K/AKT pathway manifested by enhanced expression of PI3K p110α and p-AKT. Together, the present findings report the gastroprotective actions of MP mediated via its anti-inflammatory, antioxidant, and antiapoptotic actions. The underlying molecular mechanisms involve, at least partly, the modulation of MAPKs, NF-κB and PI3K/AKT transduction.

BACKGROUND/AIMS: The clinical utility of 5-fluorouracil (5-FU) is limited by its nephrotoxicity. Camel milk (CM) has previously displayed beneficial effects in toxicant-induced nephropathies. The current study aimed to investigate the potential of CM to attenuate 5-FU-induced nephrotoxicity in rats.

METHODS: Renal tissues were studied in terms of oxidative stress, inflammation and apoptosis. The levels of renal injury markers, inflammatory cytokines along with NOX-1, Nrf-2 and HO-1 were assessed by ELISA. The expression of MMP-2, MMP-9, NF-κBp65, p53, Bax and PCNA were detected by Immunohistochemistry. To gain an insight into the molecular signaling mechanisms, we determined the effect of CM on MAPKs, NF-κB and PI3K/Akt/eNOS pathways by Western blotting.

RESULTS: CM lowered 5-FU-triggered increase of creatinine, BUN, Kim-1 and NGAL renal injury biomarkers and attenuated the histopathological aberrations. It suppressed oxidative stress and augmented renal antioxidant armory (GSH, SOD, GPx, TAC) with restoration of NOX-1, Nrf-2 and HO-1 levels. CM also suppressed renal inflammation as indicated by inhibition of MPO, TNF-α, IL-1β, IL-18 and MCP-1 proinflammatory mediators and downregulation of MMP-2 and MMP-9 expression with boosting of IL-10. Regarding MAPKs signaling, CM suppressed the phosphorylation of p38 MAPK, JNK1/2 and ERK1/2 and inhibited NF-κB activation. For apoptosis, CM downregulated p53, Bax, CytC and caspase-3 proapoptotic signals with enhancement of Bcl-2 and PCNA. It also enhanced PI3K p110α, phospho-Akt and phospho-eNOS levels with augmentation of renal NO, favoring cell survival. Equally important, CM preconditioning enhanced 5-FU cytotoxicity in MCF-7, HepG-2, HCT-116 and PC-3 cells, thus, justifying their concomitant use.

CONCLUSION: The current findings pinpoint, for the first time, the marked renoprotective effects of CM that were mediated via ROS scavenging, suppression of MAPKs and NF-κB along with activation of PI3K/Akt/eNOS pathway.

Methotrexate (MTX) is a classical chemotherapeutic agent with nephrotoxicity as the most disturbing adverse effect. So far, its underlying molecular mechanisms, particularly PI3K/Akt/eNOS transduction, are inadequately explored. Several antioxidant modalities have been characterized to ameliorate MTX-induced renal injury. In this regard, Camel milk (CM) is a natural product with recognized antioxidant and anti-inflammatory features. Thus, the current study aimed to investigate the potential ameliorating effects of CM in MTX-induced kidney injury in rats. Renal tissues were studied in terms of renal injury markers, histopathology, oxidative stress, apoptosis and PI3K/Akt/eNOS signaling. CM was orally administered (10 ml kg-1) and the renal injury was induced by a single i.p. injection of MTX (20 mg kg-1). Interestingly, CM dose-dependently attenuated MTX-triggered increase of BUN and serum creatinine and renal Kim-1 expression and mitigated the renal histopathological changes. CM counteracted renal oxidative stress as manifested by lowering of lipid peroxides, restoration of NOX-1 levels and augmentation of the antioxidant defenses e.g., GSH, SOD, GPx and total antioxidant capacity. With respect to apoptosis, CM curbed the cleavage of PARP and caspase-3, downregulated p53, Bax and Cyt C proapoptotic signals and enhanced Bcl-2 and PCNA levels. In the same context, CM activated the prosurvival PI3K/Akt/eNOS pathway via enhancing PI3K p110, phospho-Akt and phospho-eNOS levels. Equally important, CM preconditioning did not interfere with MTX cytotoxicity in TK-10 or PC-3 cancer cells. Together, the current findings demonstrate, for the first time, the renoprotective effects of CM in MTX-induced kidney injury via activation of PI3K/Akt/eNOS signaling and combating oxidative stress and apoptosis.

UVA comprises more than 90% of the solar UV radiation reaching the Earth. Artificial lightening lamps have also been reported to emit significant amounts of UVA. Exposure to UVA has been associated with dermatological disorders including skin cancer. At the molecular level, UVA damages different cellular biomolecules and triggers inflammatory responses. The current study was devoted to investigate the potential protective effect of L-carnitine against UVA-induced skin tissue injury using rats as a mammalian model. Rats were distributed into normal control group (NC), L-carnitine control group (LC), UVA-Exposed group (UVA), and UVA-Exposed and L-carnitine-treated group (UVA-LC). L-carnitine significantly attenuated UVA-induced elevation of the DNA damage markers 8-oxo-2'-deoxyguanosine (8-oxo-dG) and cyclobutane pyrimidine dimers (CPDs) as well as decreased DNA fragmentation and the activity of the apoptotic marker caspase-3. In addition, L-carnitine substantially reduced the levels of lipid peroxidation marker (TBARS) and protein oxidation marker (PCC) and significantly elevated the levels of the total antioxidant capacity (TAC) and the antioxidant reduced glutathione (GSH) in the skin tissues. Interestingly, L-carnitine upregulated the level of the DNA repair protein proliferating cell nuclear antigen (PCNA). Besides it mitigated the UVA-induced activation of the oxidative stress-sensitive signaling protein p38 and its downstream target c-Fos. Moreover, L-carnitine significantly downregulated the levels of the early response proinflammatory cytokines TNF-α, IL-6, and IL-1β. Collectively, our results highlight, for the first time, the potential attenuating effects of L-carnitine on UVA-induced skin tissue injury in rats that is potentially mediated through suppression of UVA-induced oxidative stress and inflammatory responses.

Doxorubicin (DOX) is an anthracycline antibiotic that is used frequently for treatment of various types of malignancies. Hepatotoxicity is one of the serious complications of DOX. The aim of this study was to explore the effect of different doses of irbesartan on doxorubicin-induced hepatotoxicity in mice. Sixty male BALB/c mice were divided into six equal groups as follows: Control group; DOX group; Irbesartan (Small dose) group; Irbesartan (Large dose) group; DOX + Irbesartan (Small dose) group and DOX + Irbesartan (Large dose) group. Liver weight/body weight ratio, food intake, serum albumin, alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and total bilirubin were measured. Also, tissue antioxidant enzymes, transforming growth factor beta 1 (TGF-β1), nuclear factor (erythroid-derived 2)-like 2/heme oxygenase-1 (Nrf2/HO-1) content, tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and signal transducer and activator of transcription-3 (STAT-3) were assessed. Parts of the hepatic tissues were subjected to histopathological examination. Irbesartan administration to DOX-treated mice induced significant decrease in serum ALT, AST, ALP, total bilirubin, tissue TGF-β1, TNF-α, IL-6 and liver weight/body weight ratio associated with significant increase in food intake, serum albumin, tissue Nrf2/HO-1 content, STAT-3 and antioxidant enzymes and significant improvement in the histopathological picture compared to DOX group. This improvement was significant with DOX + Irbesartan large dose compared to DOX + Irbesartan small dose. In conclusion, irbesartan - in a dose-dependent manner - might represent a promising hope for cancer patients to ameliorate DOX-induced hepatotoxicity.

Gentamycin is an aminoglycoside antibiotic that is widely employed for controlling Gram negative bacterial infections including that caused by the antibiotic-resistant Pseudomonas species. The clinical use of gentamycin is substantially limited by its side effects particularly acute kidney injury (AKI). The aim of the current study was to investigate the protective effect of the plant flavonoid troxerutin (150 mg kg-1 day-1 for 15 days) against gentamycin-induced AKI using Wistar rats as an experimental mammalian model. The results of the present work revealed that troxerutin significantly improved renal function as demonstrated by the increase in the glomerular filtration rate and the decrease in the levels of urinary albumin, urinary albumin to creatinine ratio, serum creatinine, and blood urea nitrogen (p < 0.001). In addition, troxerutin significantly attenuated gentamycin-induced renal tissue injury as indicated by the decreased protein expression of the renal tubular injury marker KIM-1, the attenuation of the renal histopathological changes, and the modulation of the oxidative stress markers as reflected by the decrease in the levels of lipid and protein oxidative modifications and the increase in the levels of reduced glutathione and total antioxidant capacity (p < 0.001). Furthermore, troxerutin down-regulated the levels of inflammatory cytokines (IL-10, TNF-α, and IL-6), attenuated apoptotic cell death, and enhanced the renal tissue regenerative capacity as demonstrated by the increase in the protein expression of the proliferating cell nuclear antigen, PCNA (p < 0.001). Collectively, the results of the current study highlight, for the first time, the ameliorating effects of troxerutin against gentamycin-induced AKI in rats that is potentially mediated via the modulation of p38 MAPK signaling as well as via antioxidant, anti-inflammatory and anti-apoptotic activities.

BACKGROUND/AIMS: Camel milk (CM) has shown beneficial anti-inflammatory actions in several experimental and clinical settings. So far, its effect on rheumatoid arthritis (RA) has not been previously explored. Thus, the current work aimed to evaluate the effects of CM in Adjuvant-induced arthritis and air pouch edema models in rats, which mimic human RA.

METHODS: CM was administered at 10 ml/kg orally for 3 weeks starting on the day of Freund's adjuvant paw inoculation. The levels of TNF-α and IL-10 were measured by ELISA while the protein expression of NF-κBp65, COX-2 and iNOS was detected by immunohistochemistry. The expression of MAPK target proteins was assessed by Western blotting.

RESULTS: CM attenuated paw edema, arthritic index and gait score along with dorsal pouch inflammatory cell migration. CM lowered the TNF-α and augmented the anti-inflammatory IL-10 levels in sera and exudates of arthritic rats. It also attenuated the expression of activated NF-κBp65, COX-2 and iNOS in the lining of the dorsal pouch. Notably, CM inhibited the MAPK pathway signal transduction via lowering the phosphorylation of p38 MAPK, ERK1/2 and JNK1/2 in rat hind paws. Additionally, CM administration lowered the lipid peroxide and nitric oxide levels and boosted glutathione and total anti-oxidant capacity in sera and exudates of animals.

CONCLUSION: The observed CM downregulation of the arthritic process may support the interest of CM consumption as an adjunct approach for the management of RA.

Vascular endothelial dysfunction plays a key role in the pathogenesis of Alzheimer's disease (AD). Patients with AD have displayed decreased circulating endothelial progenitor cells (EPCs) which repair and maintain the endothelial function. Transplantation of EPCs has emerged as a promising approach for the management of cerebrovascular diseases including ischemic stroke, however, its impact on AD has been poorly described. Thus, the current study aimed at investigating the effects of bone marrow-derived (BM) EPCs transplantation in repeated scopolamine-induced cognitive impairment, an experimental model that replicates biomarkers of AD. Intravenously transplanted BM-EPCs migrated into the brain of rats and improved the learning and memory deficits. Meanwhile, they mitigated the deposition of amyloid plaques and associated histopathological alterations. At the molecular levels, BM-EPCs blunted the increase of hippocampal amyloid beta protein (Aβ), amyloid precursor protein (APP) and reinstated the Aβ-degrading neprilysin together with downregulation of p-tau and its upstream glycogen synthase kinase-3β (GSK-3β). They also corrected the perturbations of neurotransmitter levels including restoration of acetylcholine and associated esterase along with dopamine, GABA, and the neuroexitatory glutamate. Furthermore, BM-EPCs induced behavioral recovery via boosting of vascular endothelial growth factor (VEGF), nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and its upstream cAMP response element binding (CREB), suppression of the proinflammatory tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), and upregulation of interleukin-10 (IL-10). BM-EPCs also augmented Nrf2 and seladin-1. Generally, these actions were analogous to those exerted by adipose tissue-derived mesenchymal stem cells (AT-MSCs) and the reference anti-Alzheimer donepezil. For the first time, these findings highlight the beneficial actions of BM-EPCs against the memory deficits and AD-like pathological dysfunction.

Lead is a biohazardous metal that is commonly involved in human illness including renal injury. Although it is a non-redox reactive metal, lead-induced renal injury is largely based on oxidative stress. The current work aimed at exploring the possible protective effect of γ-glutamyl cysteine (γGC) against lead-induced renal injury. Rats were allocated to normal and γGC control groups, lead-treated group, and lead and γGC-treated group. γGC alleviated lead-induced renal injury as evidenced by attenuation of histopathological aberration, amelioration of oxidative injury as demonstrated by significant reduction in lipid and protein oxidation, elevation of total antioxidant capacity, and glutathione level. The activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) was significantly elevated. γGC significantly decreased levels of the proinflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β and the activity of the apoptotic marker caspase-3. In addition, γGC reduced kidney lead content, enhanced weight gain, and improved renal function as demonstrated by reduced serum levels of urea and creatinine. Importantly, γGC upregulated proliferating cell nuclear antigen (PCNA) expression, denoting enhanced renal regenerative capacity. Together, our findings highlight evidence for alleviating effects of γGC against lead-induced renal injury that is potentially mediated through diminution of oxidative tissue injury, reduction of inflammatory response, attenuation of apoptosis, and enhancement of renal regenerative capacity.