[Effects of Bcl-2 family on the thyroid cell apoptosis of experimental autoimmune thyroiditis mice induced by iodine].

OBJECTIVE

To study the effect of Bcl-2 family members on experimental autoimmune thyroiditis(EAT) and explore the pathogenesis of autoimmune thyroiditis.

METHODS

Twenty-four female 4-5 week old NOD-SCID mice were randomly divided into four groups(six mice in each group): control group, high iodine group, poly(I:C) group and high iodine combined with poly(I:C) group. Control group and poly(I:C) group were fed with distilled water, while the high iodine group and high iodine combined with poly(I:C) group were supplied with 0. 05% NaI in their drinking water for 16 weeks. Poly(I:C) group and high iodine combined with poly(I:C) group received intraperitoneal injection of 100 μL poly(I:C)(1 μg/μL) at monday, wednesday and friday of the 11 th and 15 th week. Serum and thyroid were obtained at the last day of the 16 th week. The EAT model was confirmed by ELISA method and pathological HE staining, the apoptosis of thyroid cell were detected by TUNEL method and Cyt-C immunocytochemistry assay, and the mRNA levels of Bcl-2 family members in thyroid were determined by real-time qPCR method.

RESULTS

EAT model was established using NOD-SCID mice through high-iodine feeding combined with poly(I:C) intraperitoneal injection. The degree of cell apoptosis and the Cyt-C expression levels were positively correlated with inflammation in thyroid follicular epithelial cells. The mRNA levels of Noxa, PUMA and Bid of high iodine group and high iodine combined with poly(I:C) group were higher than those in control and poly(I:C) groups(P<0. 05).

CONCLUSION

Mitochondrial apoptosis pathway is involved in the thyroid cell apoptosis of EAT induced by high iodine, and the apoptosis may be regulated by the up-regulation of Noxa, PUMA and Bid, which belong to the pro-apoptotic members of Bcl-2 family.