不同剂量碘酸钾对大鼠甲状腺抗氧化能力影响

目的观察不同剂量碘酸钾（KIQ）对Wistar大鼠甲状腺抗氧化能力的影响。方法将Wistar大鼠随机分为6组：低碘组（LI），适碘组（NI），5倍高碘组（5HI），10倍高碘组（10HI），50倍高碘组（50HI），100倍高碘组（100HI）。喂养3，6，12个月后，检测甲状腺组织匀浆中的谷胱甘肽过氧化酶（GPx）活性、超氧化物歧化酶（s0D）活性以及丙二醛（MDA）含量。结果LI组的GPx活性、SOD活性和MDA含量均较NI组显著增高（P〈0．01）。5HI和100HI组的GPx活性和SOD活性与NI组比较差异均无统计学意义（P〉O．05）；50HI和10HI组的GPx活性在12个月时较NI组降低（P〈0．05），并且这2组的SOD活性6个月和12个月时也均较NI组降低（P〈0．05）。4个高碘组的MDA含量与NI组比较差异均无统计学意义（P〈0．05）。结论低碘导致大鼠甲状腺抗氧化系统失代偿，发生过氧化损伤；长期高碘（50HI和100HI）会使甲状腺抗氧化酶活性降低，但未出现过氧化损伤；大鼠甲状腺的抗氧化系统对高剂量碘酸钾有一定的耐受能力。关键词：碘酸钾：抗氧化能力；甲状腺

Effect of different dosage potassium iodate on anti-oxidative capability of thyroid in rats

Objective To study the effect of different dosage KIO3 on the thyroid anti-oxidative capability. Methods The rats were divided into 6 groups and given by different dosage of KIO3,those were low iodide (LI),normal iodide (NI),5 fold high iodide (5HI),10 fold high iodide (10HI),50 fold high iodide (50HI)and 100 fold high iodide (100HI),3,6 and 12 months later,the rats were sacrificed and thyroid glutathione peroxidase (GPx)activity,Superoxide Dismutase(SOD)activity and malondialdehyde (MDA)content were measured. Results The activities of GPx and SOD and the MDA content in LI group were markedly higher than those in NI group.There was no difference in the SOD and GPx activity among NI,5HI and 10HI groups.The GPx activity in 50HI and 100HI groups were lower than that in NI group after adminnistration for 12 months,but no difference between these three groups after treatment for 3 and 6 months.The SOD activity in 50HI and 100HI groups were lower than that in NI group after administration for 6 and 12 months,but no difference was found between them after treatment for 3 months.There was no difference in MDA content among NI group and 4 high iodide groups.Conclusion Low iodide intake would damage the anti-oxidative capability of thyroid in normal rats. Thyroid had a strong anti-oxidative ability and compensative acpabilities to compete with high dosage potassium iodate intake.