高碘对豚鼠脑和甲状腺细胞凋亡及调节基因表达的影响

目的 探讨高碘对脑和甲状腺细胞凋亡及ｂｃｌ－２、ｂｏｘ基因表达的影响。方法 分别以含碘量为５０μｇ／Ｌ（适碘组）和１００００μｇ／Ｌ（高碘组）的蒸馏水喂养两个实验组的豚鼠６个月,应用流式细胞术和免疫荧光技术检测豚鼠大脑皮质、海马和甲状腺细胞凋亡率,并对ｂｃｌ－２、ｂａｘ基因蛋白表达进行定量检测。结果 高碘组大脑皮质、海马和甲状腺细胞凋亡率明显高于适碘组;高碘组大脑皮质、海马和甲状腺组织ｂｃｌ－２蛋

Effects of excessive iodine on apoptosis and expression of bcl-2, bax genes in the cells of brain and thyroid gland in guinea pigs

OBJECTIVE: To investigate the effects of excessive iodine intake on apoptosis and the expression of bcl-2, bax genes in the cells of brain and thyroid gland. METHODS: Guinea pigs, divided into two groups at random, were fed with distilled water containing iodine 50 microg/L (a control group with appropriate iodine) and 10,000 microg/L (a trial group with excessive iodine), respectively for six months. Apoptosis rate and expression of bcl-2, bax gene in the cells of cerebral cortex, hippocampus and thyroid gland in guinea pigs were quantitatively determined by flow cytometry and immunofluorescent techniques. RESULTS: The proportion of apoptosis in the cells of cerebral cortex, hippocampus and thyroid gland was significantly higher in the group with excessive iodine intake than that in the control one (P < 0.01). The level of expression of bcl-2 gene was notably decreased (P < 0.05), but that of bax was notably increased (P < 0.01), in the cerebral cortex, hippocampus and thyroid gland in the group with excessive iodine than in the control one. The ratio of bcl-2 to bax in the cerebral cortex, hippocampus and thyroid gland of the group with excessive iodine was decreased significantly (P < 0.01) than that of the control one. CONCLUSION: Excessive iodine intake may induce apoptosis in the cells of cerebral cortex, hippocampus and thyroid gland. The over-expression of bax gene and the down-regulation of bcl-2, which can then cause the decrease in a ratio of bcl-2 to bax, appear to play an important role in the course of apoptosis induced by excessive iodine intake.