硒对碘过量小鼠肝脏I型脱碘酶活性的影响

目的　研究碘过量摄入对小鼠肝脏I型脱碘酶 (IDI)活性的影响及硒的干预作用。方法　将 4 0只Balb c小鼠按体重随机分为 5组 :正常对照组、碘过量I组 (3mg L)、碘过量I+Se(1mg L)组、碘过量II组 (5mg L)以及碘过量II+Se(1mg L)组 ,分别喂饲碘过量水或碘过量 +硒水以及正常鼠饲料。 3个月后 ,取血、尿及脏器测定相关指标。结果　碘过量组小鼠出现了弥漫胶质性甲状腺肿 ;与正常对照组相比 ,两个碘过量的血清TT4水平显著升高 ,而碘过量II组血清TT3水平显著降低 ;碘可显著降低肝硒水平及I型脱碘酶活性 ,补硒可明显增加碘过量小鼠的肝硒储备 ,抑制碘过量I组脱碘酶活性的降低。结论　碘过量摄入降低小鼠肝硒水平及肝脏I型脱碘酶活性 ,可能是引起血清TT4升高、出现甲状腺肿的原因 ,补硒具有一定的干预作用。

Effect of selenium on liver type I deiodinase in iodine-excess mice

OBJECTIVE: To investigate the effect of selenium on the activities of liver type I deiodinase (IDI) in iodine-excess mice. METHODS: Forty female weanling Balb/c mice of 18-22 body weight were randomly divided into 5 groups: normal control group (N, deionized water), iodine-excess group I (IE I, 3 mg/L Iodine water), IE I + Se group (+ 1 mg/L Se water), iodine-excess group II (IE II, 5 mg/L Iodine water) and IE II + Se group (+ 1 mg/L Se water), and they were fed with standard diets and different level of iodine and selenium water for 12 weeks. RESULTS: Iodine-excess groups show diffused colloid goiter; Serum TT4 of two iodine-excess groups were significantly higher than Normal control, and TT3 of IE II decreased significantly; The selenium level and IDI activity of mice liver was decreased significantly in iodine-excess group, but no difference between IE I and IE II. CONCLUSION: Iodine-excess intake can decrease the selenium level and IDI activity of mice liver, which maybe is the reason to increase the serum TT4 level and lead to goiter, and selenium can alleviate that.