RESUMEN
Lead is a heavy metal found in earth’s crust. It is a widespread and insidious environmental toxin known as a severe and aggressive contaminant to human and animal organisms’ health status.This work is aimed at evaluating the effect of aqueous extract of Ocimum gratissimum (OG) on lead induced changes in the thymus of adult albino wistar rats.Thirty five male Wistar rats were used in the study and were randomly divided into seven groups with five rats in eachgroup. The rats in Group one (G1) served as the Control and received distilled water. Group 2 received 120 mg/kg body weight (bwt) of lead acetate, G3 received 375mg/kg bwt of OG only. G4 received 120 mg/kg bwtof lead acetate and OG extract at 375 mg/kg bwt., G5 received 120 mg/kg bwt of lead and OG at 750 mg/kg bwt. G6 received 375mg/kg bwt of OG in two weeks followed by120 mg/kg bwt of lead acetate for one week, while G7 received 120 mg/kg bwt of lead acetate and Vitamin C at 11900mg/kg. All the administrations were carried out orally for twenty one (21) days. At the end of the administration, the rats were fasted for 24 hours. They weighted and humanely sacrificed via cervical dislocation.The thymus were harvested in all the groups and prepared for histological studies using routine haematoxylin and eosin (H&E) staining techniques. The result of the present study shows that lead possessed a distortive effect in the histoarchitecture of thymus of the wistarrat in G2 when compared with G1. Treatment of these experimental animals with vitamin C prove to posses more ameliorative effect in restoring the histoarchitecture on lead toxicity in the thymus closed to normal than OG.Therefore, it is suggested that aqueous extract OG can act via the same pathway as vitamin C, in maintaining the normal histological structures of the thymus of adult albino wistar rat exposed to lead toxicity