Investigation of the Antioxidant Signalling Mechanisms of Rosmarinus officinalis L. in an Aniline-induced Splenic Toxicity Rat Model
Background: Aniline is an industrial chemical whose reactive metabolites induce oxidative stress and structural damage in splenic tissue, making aniline-induced splenic toxicity in rats a well-established experimental model for evaluating protective interventions. Rosmarinus officinalis L. (rosemary) possesses potent antioxidant and anti-inflammatory phytochemicals that may mitigate chemically induced tissue injury. Aim: To investigate the antioxidant-mediated splenoprotective effects of Ethanolic Rosemary Extract (ERE) against aniline-induced splenic toxicity in male Wistar rats. Methods: Male Wistar rats (200-250 g) were randomly divided into five groups (n = 6) and treated for 30 days. Splenic toxicity was induced by oral administration of aniline hydrochloride (50 mg/kg/day). Protective treatment groups received ERE at doses of 100 or 200 mg/kg/day orally, while citric acid (100 mg/kg/day, p.o.) served as the reference standard. Physiological parameters, oxidative stress biomarkers, antioxidant enzyme activities (GSH and CAT), ATPase activity, serum biochemical indices, histopathological changes, and hemosiderin deposition were assessed. Statistical analysis was performed using one-way ANOVA, with p<0.05 considered statistically significant. Results: Aniline administration produced splenomegaly, excessive iron accumulation, elevated lipid peroxidation, impaired antioxidant defences, reduced ATPase activity, and pronounced histopathological alterations including fibrosis and disruption of normal splenic architecture. Treatment with ERE significantly ameliorated these toxic effects in a dose-dependent manner. Rosemary extract restored antioxidant enzyme levels, reduced lipid peroxidation and nitric oxide production, improved ATPase activity, decreased hemosiderin deposition, normalised haematological and biochemical parameters, and preserved splenic histoarchitecture. The higher dose (200 mg/kg) demonstrated the greatest protective efficacy. Conclusion: ERE effectively protects against aniline-induced splenic toxicity by attenuating oxidative stress, restoring antioxidant defences, reducing iron accumulation, and preserving tissue architecture, suggesting its potential as a natural splenoprotective agent. Major Findings: ERE significantly ameliorated oxidative stress, restored antioxidant enzyme activity, improved haematological indices, reduced splenic iron overload, and preserved splenic histoarchitecture, with the 200 mg/kg dose producing the greatest protective effect.