Effect of PM2.5 exposure on thyroid function in SD rats / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the effect of PM2. 5 exposure on the thyroid function in male SD rats. Methods Adult Sprague-Dawley rats were divided into " filtered air" ( FA) and " PM2.5" groups. These rats exposed to the 2 kinds of air for 12 weeks were killed and their plasma and thyroid tissues were taken for investigation. The morphological status and pathological changes of thyroid tissue were observed after H&E staining. The levels of triiodothyronine ( T3 ) , free triiodothyronine ( FT3 ) , thyroxine( T4 ) , free thyroxine ( FT4 ) , anti-thyroglobulin antibody ( TGAb ) , anti-thyroid peroxidase antibody ( TPOAb ) , thyrotropin ( TSH ) , tumor necrosis factor α ( TNF-α), and interleukin-6 ( IL-6) in rats were measured by ELISA. Results The results showed that there was no significant difference in body weight between two groups after 12 weeks of exposure to either filtered air or PM2.5. No pathological changes and significant differences were observed in the thyroid tissues of two groups after HE staining. There were no significant differences in plasma levels of T4 , T3 , FT3 , TNF-α, and IL-6 between two groups. However, compared with rats exposed to filtered air, rats exposed to PM2.5 had significantly lower plasma FT4[ (3.81 ± 1.23) vs (6.02 ± 2.40) pmol/L, P＜0.01] and higher TSH [ (5.63 ± 1.74) vs (4.29 ± 1.37) mU/L, P＜0. 05 ] levels. Conclusion The exposure to PM2. 5 for a period of 12 weeks may lead to hypothyroidism in rats.