ABSTRACT
OBJECTIVE: To test the impact of subchronically administered Bismerthlazol on the thyroid morphosis of rats. METHODS: One hundred SD rats were randomly divided into one negative control group and four experimental groups with 7.0, 27.9, 111.7, and 447.0 mg/kg daily doses of Bismerthlazol, respectively. The Bismerthlazol was administered by gavage for 90 d. At the end of the experiment, the thyroids of the rats were harvested and weighted. The pathological changes of the thyroids were observed under light microscopes. The positive expression of PCNA in the thyroid glands were examined by histochemistry methods. RESULTS: Increased coefficients of thyroid gland weight were found in the experimental groups (P < 0.01). The thyroid glands showed different hyperplasia of follicular cells. Increased positive cells of PCNA were observed in the experimental groups (P < 0.05 or P < 0.01) except for the 7.0 mg/kg dose group. CONCLUSION: Long-time administered Bismerthlazol causes thyroids hyperplasia in rats. Further study on the mechanisms is warranted.
