Mercury chloride-induced hippocampal toxicity in Wistar rats: antioxidant activity of folic acid

Mercury chloride (HgCl2) is a well-known neurotoxicant with detrimental effects on the central nervous system, particularly the hippocampus, a region crucial for learning and memory processes. Folic acid (FA), also known as the synthetic form of vitamin B9, plays a crucial role in various bodily functions. Accordingly, this study investigated the possible neuroprotective activity of FA against HgCl2-induced hippocampal toxicity in Wistar rats. Forty-eight Wistar rats were assigned into six groups (n=8) with the following treatment regimen for 28 days: A (control); B (4 mg/kg bw HgCl2); C (5 mg/Kg bw FA + 4 mg/kg bw HgCl2); D (10 mg/kg bw FA + 4 mg/kg bw HgCl2); E (5 mg/kg bw FA); F (10 mg/kg bw FA). After treatment, neurobehavioral, antioxidant enzymes, lipid peroxidation, mercury concentration, and histological assessments were done. Results showed significantly (p < 0.05) impaired cognition and antioxidants, as well as elevated lipid peroxidation and mercury concentration in the HgCl2-treated rats when compared to the control. In addition, the hippocampus of HgCl2-treated rats exhibited severe atrophy and vacuolated pyramidal cells and astrocytes, signifying hippocampal dysfunction. However, pretreatment of HgCl2-treated rats with FA significantly (p < 0.05) mitigated these neurobehavioural, biochemical, and histological alterations. Taken together, the neuroprotective activity of FA against HgCl2-induced hippocampal toxicity is mediated, possibly through its antioxidant and metal-chelation effects.