Effects of different concentration of iodine on the proliferation and apoptosis of papillary thyroid carcinoma B2-7 cell

Objective To observe the effects of different concentration of iodine on the prolifera-tion and apoptosis of papillary thyroid carcinoma B2-7 cell.Methods Papillary thyroid carcinoma B2-7 cells were cultured in vitro and divided into control group and different concentration kalium iodide intervene groups,concentration of iodine were 0,10-7,10-5,10-3 mol/L,respectively,the intervening time were 24,72 and 120 h.The cell proliferation was measured by methyl thiazolyl tetrazolium (MTT) assay.The cell apoptosis was analyzed by AnnexinV-FITC/PI flow cytometry assay and expression of apoptosis suppressor Bcl-2 was detected by quantitive RT-PCR.Results MTT assay showed the absorbance value of 10-7 mol/L group at 72 h was higher (P ＜ 0.05),and there were no statistical differences at 24,120 h compared with control group,as well as 10-5 mol/L group at intervention time 24,72 and 120 h (P ＞0.05).While absorbance values of 10-3 mol/L group at three intervention time were lower than those of control group (P ＜ 0.05).The ratio of apoptosis cells among intervention groups had no statistical difference at 24 h compared with control group (all P＞0.05).At 72 h,the ratio of apoptosis cells in 10-3 mol/L group increased (P ＜0.05),while in 10-7,10-5mol/L groups,the differences had no statistical significance (P ＞0.05).At 120 h,the ratio of apoptosis cells in each intervention groups were all higher than those in control group (P ＜0.05).There were no statistical differences in the expression of Bcl-2 among intervention groups at 24 h compared with control group (P ＞ 0.05).However,its expression in 10-3 mol/L group was lower than that of control group at 72 h (P ＜ 0.05),and had no statistical differences in 10-5,10-7 mol/L groups (all P ＞0.05).At 120 h,the expression of Bcl-2 was down-regulated in 10-3 mol/L group and up-regulated in 10-7 mol/L group.Conclusion High iodine could inhibit proliferation of papillary thyroid carcinoma B2-7 cell and promote its apoptosis in vitro. Key words: Iodine;  Papillary thyroid carcinoma;  Proliferation;  Apoptosis