脓毒症大鼠甲状腺损害的研究

A study on thyroid injury in rats with sepsis

目的探讨脓毒症大鼠甲状腺超微结构和功能的变化。方法实验地点为福建医科大学动物房、福建省立医院心血管研究所重点实验室、福建医科大学电镜室。清洁级SD健康雄性大鼠32只，体质量180—220g，随机数字法随机分为对照组（C组）、12h组、24h组及36h组，每组大鼠8只，12h组、24h组及36h组合称脓毒症组。脓毒症组采用盲肠结扎穿孔术造脓毒症模型。12h组、24h组、36h组分别于术后12h、24h、36h采取标本。血液标本离心后取血清用于检测甲状腺功能指标（1、3、Td、fT3、fT4、TSH）；甲状腺组织标本用于Caspase-3蛋白表达、细胞凋亡指数及超微结构检测；统计学处理采用SPSS19．0统计软件包完成，各组大鼠甲状腺激素水平的比较采用单因素方差分析。因凋亡指数及Caspase-3表达灰度值均非正态分布，以中位数（P25，P75）表示，多组间比较采用Kruskal—WalIis H检验，如差异具有统计学意义，两两比较采用Nemenyi检验。结果脓毒症组大鼠T4水平在12h、24h、36h组均较C组明显降低（P〈0．05）；fT3、fT4水平在24h、36h组较C组显著降低（P〈0．05）；乃水平在36h组较C组显著降低（P〈0．05）。24h组Caspase-3蛋白表达明显高于C组（P〈0．05）；24h、36h组甲状腺组织凋亡指数明显高于C组（P〈0．05）。电镜下，脓毒症组甲状腺滤泡上皮细胞出现细胞核形态变化，胞质内被空泡取代，甚至胞膜裂解，细胞核固缩。结论脓毒症时血清甲状腺激素水平发生改变，表现同于甲状腺病态综合征，组织Caspase-3蛋白表达及细胞凋亡增加，电子显微镜下可见甲状腺滤泡上皮出现明显病理改变。

Objective To explore the effects of sepsis on the uhrastructure and function of thyroid in rats. Methods This study was performed in the Animal Department of Fujian Medical University, the Key Laboratory of Fujian Provincial Cardiovascular Institute and the Electron Microscopic Department of Fujian Medical University. Thirty-two pathogen-free male Sprague-Dawley rats weighing 180 -220 g selected, and were randomly （random number） divided into control group （C group, n =8）, 12 hour group （n =8）, 24 hour group （n =8） and 36 hour group （n =8）. The 12 h group, 24 h group and 36 h group were established to be sepsis groups. The sepsis model was made by cecal ligation and puncture （CLP）. The samples of blood and thyroid tissue of rats in 12 h group were taken 12 hours after modeling, and then the same procedure was done in the rats of 24 h group and 36 h group separately 24 hours and 36 hours after modeling. Blood serum was obtained by centrifugation to detect the thyroid function using measurement of different of kinds of hormones （33, T4, fI3, iT4, TSH） . Thyroid tissue was available to determine the expression of caspase-3, cell apoptosis and change of ultra-microstructure. Raw data were analyzed using SPSS19. 0 software. Caspase-3 grey value was determined by Image J software. Thyroid hormone levels were presented as mean ＋ standard deviation. The differences in levels of different kinds of thyroid hormone among all the groups were determined by one-way ANOVA. TUNEL positive staining and caspase-3 expression were presented as median （P25, P75）. Results Compared to the control group, the T4 decreased significantly （P〈0.05） in the 12 h group, the 24 h group and the 36 h group, both the fT3 and the fT4 decreased significantly in the 24 h group and the 36 h group （ P 〈 0. 05 ）, and the q3 decreased significantly in the 56 h group （ P 〈 0. 05）. The expression of caspase-3 in the 24 h group was higher than that in the C group （ P 〈 0. 05 ） . There was significant difference in rate of cell apoptosis in thyroid tissue among those four groups, and both the 24 h group and the 36 h group had higher rate of cell apoptosis than the C group significantly （P 〈 0. 05） . In those sepsis groups, a series of pathological ultrastructural changes were found in thyroid follicular epithelial cells as following： the nucleus became smaller and more distinctly stained, and quite a few vacuoles were visualized in cell. Furthermore, the cell membrane was broken, and nuclei showed pyknosis. Conionelus In sepsis rats, the significant changes of different kinds of thyroid hormone in serum are similar to those found in the thyroidal illness syndrome, the expression of caspase-3 and cell apoptosis in thyroid tissue increase, and pathological change of thyroid follicular epithelial cells can be observed under electron microscopy.