Impact of Fipronil Sulfone on Oxidative Stress Biomarkers and Thyroid Hormones in Male Albino Rats

The current 28-day repeated dose oral toxicity study in rats was carried out to assess the toxicity of fipronil sulfone. Male albino rats (4 groups of 5 animals) were administered fipronil sulfone via gavage at doses of 0.01, 0.1 and 1.0 mg/kg bw/day. The levels of both total protein and creatinine significantly increased after fipronil sulfone treatment in a dose-dependent manner as compared to control. Moreover, the activity of aspartate aminotransferases (AST), alanine aminotransferases (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were highly significant increased
compared to the control group. Highly significant changes in all oxidative stress biomarkers; superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST), glutathione peroxidase (GPx), glutathione reduced (GSH) and lipid peroxidation (LPO) were observed also in liver tissues at the treatment of 1.0 mg/kg bw/day. Fipronil sulfone treatments were also associated with an increase in serum thyroid-stimulating hormone (TSH) levels after 28 days at all tested doses. The triiodothyronine (T3) and thyroxine (T4) serum concentrations were 49 and 43% lower in fipronil sulfone treated
rats, respectively at 1.0 mg/kg as compared to untreated rats after 28 days of treatment. This highlights the need to further investigate the contribution of fipronil sulfone to the fipronil-induced thyroid disruption.These results also show promise for detailed analyses of these biomarkers and their linkages to biological pathways.