海藻乙醇提取物对大鼠甲状腺肿大的影响

Effect of Ethanol Extract of Seaweed on Goiter in Rats

[目的]研究海藻乙醇提取物(简称“醇提物”)对甲硫氧嘧啶(MTU)引起的大鼠甲状腺肿大的影响。[方法]将72只Wistar大鼠随机分为空白组、模型组、阳性对照组和海藻醇提物低、中、高剂量组,每组12只。除空白组外,余组采用灌喂MTU溶液14 d复制甲状腺肿大模型。造模成功后,阳性对照组灌胃给予左甲状腺素钠片溶液(每日剂量为20μg/kg);海藻醇提物低、中、高剂量组分别灌胃给予相应剂量的海藻醇提物溶液(每日剂量分别为0.54 g/kg、1.08 g/kg、2.16 g/kg);空白组和模型组每日灌胃给予等量生理盐水。各组灌胃容量均为10 ml/kg。连续给药28 d,给药期间需隔天灌胃给予MTU 1次以保证模型的稳定。28 d后采用10%水合氯醛进行腹腔注射麻醉,腹主动脉取血进行处死。取大鼠肝脏、心脏、甲状腺组织称重,计算脏器指数;用HE染色法观察甲状腺组织病理形态学变化;采用酶联免疫吸附法(ELISA)检测大鼠血清中FT3、FT4和TSH的含量。[结果]与空白组比较,模型组大鼠甲状腺指数升高(P<0.01),甲状腺组织小叶排列紊乱,滤泡皱缩,上皮细胞增厚,间质炎性细胞浸润,血清中FT3、FT4含量显著降低,TSH含量显著升高(P<0.05或P<0.01)。与模型组比较,海藻醇提物低、中、高剂量组均能降低大鼠甲状腺指数(P<0.05或P<0.01),并改善MTU引起的甲状腺损伤病理形态;海藻醇提物低、高剂量组血清中的FT3含量升高(P<0.05);海藻醇提物低剂量组血清中FT4含量升高(P<0.05);海藻醇提物中、高剂量组血清中TSH含量显著降低(P<0.01)。[结论]海藻醇提物对MTU引起的大鼠甲状腺肿大及甲状腺组织病理学形态变化具有明显的改善作用,可能与海藻醇提物能够升高FT3、FT4水平,降低TSH的表达量有关。

[Objective]To study the effect of ethanol extract of seaweed("ethanol extract"for short)on goiter in-duced by methylthiouracil(MTU)in rats.[Methods]Seventy-two Wistar rats were randomly divided into blank group,model group,positive control group and low,medium and high dose groups of seaweed alcohol extract,with 12 rats in each group.Except the blank group,the other groups were fed with MTU solution for 14 days to replicate the goiter mod-el.After successful modeling,the positive control group was given levothyroxine sodium tablet solution(daily dose of 20μg/kg)by gavage.The low,medium and high dose groups were given the corresponding dose of seaweed alcohol ex-tract solution by gavage(daily doses were 0.54 g/kg,1.08 g/kg,2.16 g/kg);the blank group and the model group were given the same amount of normal saline daily.The intragastric volume of each group was 10 ml/kg.The continuous ad-ministration was conducted for 28 days,MTU was administered intragastrically every other day to ensure the stability of the model.After 28 days,10%chloral hydrate was used for intraperitoneal injection anesthesia,and blood was taken from the abdominal aorta for execution.The liver,heart and thyroid tissues of rats were weighed and the organ index was calculated.The pathological changes of thyroid tissue were observed by HE staining.The contents of FT3,FT4 and TSH in serum of rats were detected by enzyme-linked immunosorbent assay(ELISA).[Results]Compared with the blank group,the thyroid coefficient of the model group was increased(P<0.01),the thyroid tissue lobules were disor-dered,the follicles were shrunk,the epithelial cells were thickened,and the interstitial inflammatory cells were infiltrat-ed.The contents of FT3 and FT4 in serum were significantly decreased,and the content of TSH was significantly in-creased(P<0.05 or P<0.01).Compared with the model group,the low,medium and high dose groups of seaweed alco-hol extract could reduce the thyroid coefficient of rats(P<0.05 or P<0.01)and improve the pathological morphology of thyroid injury caused by MTU.The content of FT3 in serum of low and high dose groups increased(P<0.05).The con-tent of FT4 in the serum of the low-dose group was increased(P<0.05).The content of TSH in serum of medium and high dose groups of seaweed alcohol extract was significantly decreased(P<0.01).[Conclusion]The ethanol extract of seaweed has a significant improvement effect on goiter and pathological changes of thyroid tissue in rats induced by MTU,which may be related to the increase of FT3 and FT4 and the decrease of TSH expression.