Effects of iodine intake on the orthotopic nude mouse model of human papillary thyroid carcinoma cell line TPC-1 / 中华内分泌代谢杂志

ABSTRACT

Objective To observe the effects of different iodine intake on the thyroid tumor growth and thyroid function in the orthotopic nude mice model of human papillary thyroid carcinoma (PTC) cell line TPC-1.Methods Human PTC cell line TPC-1 (2 × 105) was injected into the left thyroid gland of nude mice.After the operation,the nude mice were randomly divided into three groupslow iodine group (LI),normal iodine group (NI),and high iodine group(HI,50 folds of normal iodine) based on the iodine levels contained in their diet.4 and 12 weeks later,the nude mice were executed,then their thyroid tumors were removed and weighted.The levels of urinary iodine were measured with As3+-Ce4+ catalytic spectrophotometry using ammonium persulfate digestion method.The thyroid hormone level was detected using chemiluminescent immunoassay.The morphology and structure of thyroid tumor tissue was observed by microscope.Results The iodine intervention feeding was successful according to urinary iodine level of LI,NI,and HI groups,paralleled to their iodine intakes.However,the difference of the weight of thyroid tumor in three groups had no statistical significance(P＞0.05).At 4 weeks,compared with control group,the levels of thyroid hormones were normal in NI group,while lower T4 and normal T3 were found in LI group.However,T4 was higher and T3 was lower in HI group (P＜0.05).At 12 weeks,the levels of thyroid hormones all were decreased due to the enlargement of thyroid gland tumor in NI,LI and HI groups.T4 and T3 in LI group were the lowest among three groups,even T4 was below detection limit.T4 was normal and T3 was lower in HI group as compared to control group.Conclusion Iodine intake may not significantly affect tumor growth in the orthotopic nude mice model of human PTC cell line TPC-1,but it has a significant effect on the synthesis of thyroid hormones.