高碘调控PTEN诱导甲状腺细胞凋亡的实验研究

High iodine induces apoptosis in thyroid cells by regulating PTEN

目的探讨高碘调控第10号染色体缺失的磷酸酶及张力蛋白同源的基因(PTEN)对甲状腺细胞凋亡的影响及其机制。方法以不同浓度(0、10 mmol/L、20 mmol/L、40 mmol/L)碘化钾染毒人正常甲状腺Nthy-ori3-1细胞24 h后,采用RT-PCR和Western blot检测PTEN mRNA和蛋白的表达。将Nthy-ori3-1细胞随机分为空白组(不做处理)、髙碘组(以40 mmol/L碘化钾染毒48 h)、髙碘+空载体组(转染pc DNA3.0质粒后,以40 mmol/L碘化钾染毒48h)和髙碘+PTEN组(转染pc DNA3.0-PTEN质粒后,以40 mmol/L碘化钾染毒48 h)。流式细胞仪检测各组细胞的凋亡率,RT-PCR检测细胞中PTEN mRNA表达,Western blot检测PTEN、Bax和Bcl-2蛋白的表达。结果 10 mmol/L、20 mmol/L和40 mmol/L碘化钾染毒后Nthy-ori3-l细胞中PTEN mRNA和蛋白的表达水平均明显升高(P<0.05),且20 mmol/L剂量组和40 mmol/L剂量组明显高于10 mmol/L剂量组(P<0.05),而20 mmol/L剂量组和40 mmol/L剂量组差异无显著性(P>0.05)。与空白组相比,髙碘组、髙碘+空载体组和髙碘+PTEN组的凋亡率、PTEN mRNA表达和PETN、Bax蛋白表达均显著升高,而Bcl-2蛋白表达均明显降低(P<0.05);与髙碘组相比,髙碘+PTEN组凋亡率、PTEN mRNA表达和PETN、Bax蛋白表达显著升高,而Bcl-2蛋白显著降低(P<0.05),而髙碘+空载体组与髙碘组各指标相比,差异无显著性(P>0.05)。结论高碘可通过上调PTEN表达诱导甲状腺细胞凋亡。

Objective To investigate the effect of high iodineon apoptosis of thyroid cells by regulating PTEN and its mechanism. Methods After 24 h of normal thyroid Nthy-ori3-1 cells exposed to potassium iodide in different concentrations （0, 10 mmol/L, 20 mmol/L, 40 mmol/L）, the expression of PTEN mRNA and protein were detected by RT-PCR and Western blot. Nthy-ori3-1 cells were randomly divided into blank group （no treatment）, high iodine group （exposure for 48 h with 40 mmol/L high iodide）, high iodine ＋ empty body group （transfected with pcDNA3.0 plasmid, exposure for 48 h with 40 mmol/L high iodide） and high iodine ＋PTEN group （transfected with pcDNA3.0-PTEN plasmid, exposure for 48 h with 40 mmol/L high iodide）, the apoptosis rate of cells in each group was measured by flow cytometry, and the expression of PTEN mRNA was detected by RT-PCR, and the expression of PTEN, Bax and Bcl-2 proteins were tested by Western blot. Results The expression levels of PTEN mRNA and protein in Nthy-ori3-l cells were significantly increased after exposure to 10 mmol/L, 20 mmol/L 40 mmol/L potassium iodide （ P 〈0.05）, and 20 mmol/L dose group and 40 mmol/L dose group were significantly higher than those of 10 mmol/L dose group （ P 〈0.05）, while 20 mmol/L dose group and 40 mmol/L dose group were not significantly different （ P 〉0.05）. Compared with the blank group, the apoptosis rate, the expression of PTEN mRNA and the expression of PETN and Bax protein in the high iodine group and high iodine＋PTEN group increased significantly, but the expression of Bcl-2 protein decreased significantly （ P 〈0.05）. Compared with the high iodine group, the apoptosis rate, the expression of PTEN mRNA and the expression of PETN and Bax protein in the high iodine ＋PTEN group increased significantly, while the Bcl-2 protein decreased significantly （ P 〈0.05）, but the difference in the iodine ＋ no-load group was not significant （ P 〉0.05）. Conclusion High iodine can induce apoptosis of thyroid cells by up regulating the expression of PTEN.