A study on thyroid injury in rats with sepsis / 中华急诊医学杂志

ABSTRACT

Objective To explore the effects of sepsis on the ultrastructure 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 (T3,T4,fT3,fT4,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 tT3 and the fT4 decreased significantly in the 24 h group and the 36 h group (P ＜0.05),and the T3 decreased significantly in the 36 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 celt 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 followingthe 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.Conionclus 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.