Effect of Silibinin on Oxidative Stress in Cobalt-Induced Hepatotoxicity in Rats

Objective The objective of this study was to investigate the effect of silibinin (SLB) on CAT, GSH-Px, and SOD enzyme activities, caspase-3, COX-2, and anti-eNOS expression cobalt (Co)-induced hepatotoxicity in rats. Methods Male Wistar albino rats (n = 24) were randomly divided into four groups: the control (0.5 mL of isotonic solution), Co (150 mg/kg/day), SLB (100 mg/kg/day), and Co + SLB (150 mg/kg/day + 100 mg/kg/day). The experimental design was carried out as a randomized complete block design. Results The catalase enzyme activity decreased to 3.55 EU/mg of protein in the Co group, while it was 19.82 EU/mg of protein in the control group (p < 0.01). In the SLB group rat liver CAT enzyme activity increased compared with the Co group (p < 0.01). According to the results of statistical analysis, a significant difference (p < 0.01) in glutathione peroxidase enzyme activity was observed between the control group and Co group. However, no statistically significant difference (p > 0.05) was observed between the Co + SLB group compared to the Co group (p > 0.05). In addition, no significant difference (p > 0.05) in superoxide dismutase enzyme activity between control and Co + SLB group groups was detected. Histopathological examination revealed marked hepatic damage in the Co group, whereas structural improvement was observed in the Co + SLB group. Immunohistochemical evaluation demonstrated increased caspase-3 and COX-2 immunoreactivity in the Co group compared to the control group. In the Co + SLB group, immunoreactivity for caspase-3 and COX-2 appeared reduced, while eNOS expression appeared more prominent compared to the Co group. Conclusion These results showed that SLB provides biochemical, histopathological, and immunohistochemical protection against Co-induced liver toxicity.