Role of Nitric Oxide, TNF-α and Caspase-3 in Lead Acetate-Exposed Rats Pretreated with Aqueous Rosmarinus officinalis Leaf Extract.

Abstract

Lead (Pb) toxicity is a worldwide significant public health challenge causing several neurological disorders. Reports indicate that plants rich in antioxidants, such as Rosmarinus officinalis (RO), can counteract Pb accumulation and its toxicity in the brain. Due to a dearth of literature evidence demonstrating the protective activity of RO against Pb toxicity, this study investigated such activity in Wistar rats. Thirty-six Wistar rats were allocated into six groups (n=6), namely I (control), II (lead acetate [Pb]; 100 mg/kg b.w.), III (100 mg/kg of RO and 100 mg/kg of Pb), IV (200 mg/kg of RO and 100 mg/kg of Pb), V (100 mg/kg b.w. of RO) and VI (200 mg/kg b.w. of RO). After 28 days, neurobehavioural, antioxidant, lipid peroxidation, apoptotic and inflammatory activities as well as the histology of the cerebellum were evaluated. Body weight, locomotion and exploration as well as antioxidant enzymes were significantly (p < 0.05) decreased in Pb-exposed rats when compared to control. Conversely, lipid peroxidation, nitric oxide, tumour necrosis factor-alpha and caspase-3 activities were significantly (p < 0.05) upregulated in the Pb-exposed rats when compared to control. These parameters were, however, significantly (p<0.05) attenuated in the RO-pretreated rats when compared to Pb-exposed rats. Cerebellar histology of the Pb-exposed rats showed severe degeneration of the Purkinje cells whereas the RO-pretreated rats showed better cerebellar architecture. These findings demonstrate that the neuroprotective activity of RO is facilitated via its effective antioxidant, anti-inflammatory and anti-apoptotic effects.