Karamala Sujatha, Chinthamaneni Srilatha, Tammineedu Chandrasekhar Rao, Pidugu Amaravathi

The objective of this study was to determine the effect chronic administration of different doses of lead acetate and study the role of Ocimum sanctum in lead toxicity as ameliorating agent in wistar rats. In the present investigation rats were randomly divided into six groups (n=36). Rats of group II and III were treated with different doses of lead acetate (60 mgs and 30 mgs / Kg.b.wt. / 3days a week respectively) and Ocimum sanctumorally @ 400mg/Kg b.wt. for other IV and V groups of rats along with lead acetate over a period of 12 weeks and the function of thyroid gland was evaluated by measuring the levels of serum thyroid hormones T3, T4 and TSH and histopathological changes of were studied in thyroid organ at every fortnight interval. Results in the present study revealed that lead acetate caused a dose dependant reductionin T3, T4 and TSH levels when compared to control. Hisopathologically thyroid shows hemorrhages and sever desquamation of epithelial cells, complete absence of acinar colloid in majority of acini, disruption of acini, atrophy of acini and interacinar fibrous tissue proliferation in majority of the animals. In Ocimumtreated groups the various thyroid hormonal levels were significantly improved and histopathological changes in thyroid gland was mild when compared to lead treated rats. Based on changes it was concluded that lead acetate at 60 mg/ Kg b.wt. and 30 mg/ Kg b.wt. for 12 weeks was toxic to rats and effect of OS in higher lead dose group was minimum and amelioration was effectively observed in lower dose levels of lead acetate