Abstract:
The present study was undertaken to assess the degree of oxidative stress and toxic effects induced by chromium on hepatic tissue
in male Wistar rats exposed to a realistic dosage of Cr(VI) (20 mg/kg/b.w./day) through drinking water, based on the levels of these
metals found in the environment, for a duration of 15, 30 and 60 days. The protective effect of melatonin (10 mg/kg) was also studied
by simultaneous administration with the metal. Levels of enzymatic and non-enzymatic antioxidants as well as lipid peroxidation were
assessed. There was a significant decrease in enzymatic as well as non-enzymatic antioxidants and an increase in the lipid peroxidation
level, which were prevented and maintained at near-normal levels by the administration of melatonin in all treatment periods. Metal
accumulation was maximal at 15 days, with gradual decreases till 60 days. Histopathological observations also demonstrated the fact
that Cr (VI) exposure leads to cytological lesions in the hepatic tissue promoting cellular necrotic/apoptotic changes, while melatonin
was able to counteract insults induced by Cr (VI) at all treatment periods. It also prevented alterations in insulin and glucose levels.
Overall, the present study suggests a duration-dependent effect of Cr on hepatic oxidative stress and cytotoxicity and shows the
potent activity of melatonin in preventing the negative effects of Cr (VI).
