Samy Mohamed

This study investigates the efficacy of idebenone, carnosine and vitamin E in ameliorating some of the biochemical indices induced in the liver of titanium dioxide nanoparticles (TiO2 NPs) intoxicated mice. Nano-anatase TiO2 (21 nm) was administered (150 mg/kg/day) for 2 weeks followed by the aforementioned antioxidants either alone or in combination for 1 month. TiO2 NPs significantly increased serum liver function enzyme activities, liver coefficient and malondialdehyde levels in hepatic tissue. They also suppressed hepatic glutathione level and triggered an inflammatory response via the activation of macrophages and the enhancement of tumor necrosis factor-α and interleukin-6 levels. Moreover, the mRNA expression of nuclear factor-erythroid-2-related factor 2, nuclear factor kappa B and Bax was up-regulated whereas that of Bcl-2 was down-regulated following TiO2 NPs. Additionally, these NPs effectively activated caspase-3 and caused liver DNA damage. Oral administration of idebenone (200mg/kg), carnosine (200mg/kg) and vitamin E (100mg/kg) alleviated the hazards of TiO2 NPs with the combination regimen showing a relatively higher effect. The histopathological examination reinforced these findings. In conclusion, oxidative stress could be regarded as a key player in TiO2 NPs-induced liver injury. The study also highlights the anti-inflammatory and the anti-apoptotic potentials of these antioxidants against the detrimental effects of TiO2 NPs.

BACKGROUND/AIM: The present study investigated the in vitro and in vivo effects of individual and combined doses of idebenone, carnosine and vitamin E on ameliorating some of the biochemical indices of nano-sized titanium dioxide (n-TiO2) in mice liver.

METHODS: The in vitro cytotoxic effect of nano-sized anatase TiO2 (21 nm) on hepatic cell lines (HepG 2) was investigated. Additionally, n-TiO2 was orally administered (150 mg/kg/day) for 2 weeks, followed by a daily intragastric gavage of the aforementioned antioxidants for 1 month.

RESULTS: n-TiO2 induced significant cytotoxicity in hepatic cell lines and elevated the levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatic total antioxidant capacity (TAC) and nitrite/nitrate (NOx) levels. Meanwhile, glutathione-S-transferase (GST) activity was significantly reduced. Moreover, RT-PCR and western blot analysis showed that n-TiO2 significantly altered the mRNA and protein expressions of transforming growth factor-beta (TGF-β1) and Smad-2, as well as vascular endothelium growth factor (VEGF). Histopathological examination of hepatic tissue reinforced these results.

CONCLUSION: Idebenone, carnosine and vitamin E ameliorated the deviated parameters with the combination regimen demonstrating the most pronounced effect. Oxidative stress, liver fibrosis and angiogenesis may be implicated in n-TiO2-induced liver toxicity.