The Relationship Between The Sepsis Rat Thyroid Functonal Alteration And The Expression Of Caspase-3and Cell Apoptosis

Objective：To investigate the change of serum thyroid hormone levels in ratswith sepsis, and their relationship with the thyroid tissue expression of Caspase-3protein and apoptosis in thyroid cells, and the change of thyroid cells’ ultramicrostructure in septic rats.Methods：Forty pathogen-free male Sprague-Dawley rots weighing180~220g,were selected and randomly divided into control group (C group), sham operationgroup (S group),12hour group (12h group),24hour group (24h group),36hourgroup (36h group),8rats in per group, C group and S group called non sepsis group,then other groups called sepsis group. The sepsis modal was reproduced by cecalligation and puncture(CLP). Sham operation group only open abdominal closure andflip intestine, without cecum ligation and perforation.12h after operation, S group and12h group rats were sacrificed and took blood and thyroid tissue, then rats of24hgroup and36h group separately have same experience in24hours and36hours afteroperation. Blood was used to test thyroid function parameters (T3, T4, fT3, fT4, TSH)and markers of inflammation (PCT, IL-6) after centrifuging. Thyroid tissue was usedto test the expression of Caspase-3, cell apoptosis and change of ultra microstructure.Results：Among the five groups, the T3level of36h group is lower than C group,there is no different between other groups. In C group, the level of T4is significantly higher than other four groups（P<0.05）, among which is no significative difference.Both in24h group and36h group, the level of and fT4is lower than C group. Theconcentration of TSH is no difference among five groups. The level of PCT and IL-6in sepsis group are both higher than non sepsis group（P<0.05）. The expression ofCaspase-3in24h group is higher than36h group and non sepsis group. Rate ofapoptosis in thyroid tissue is different among those five groups,24h group and36hgroup are both higher than12h group and non sepsis group（P<0.05）. Apoptosis rateof thyroid tissue is positive correlation with the markers of inflammation and negativecorrelation with thyroid function parameters except TSH（P<0.01）. The changes inultra structure of thyroid follicular epithelial cells were also found. In sepsis group,the nucleus of follicular epithelial cells become smaller and more deeply stained, a lotof vacuole could been found in cell. What is more, the cell membrane broke, thenucleus fall into the folliculi glandulae thyreoideae.Conclusion：The change of serum thyroid hormone levels in sepsis rats is samewith euthyroid sick syndrome, the expression of Caspase-3and cell apoptosis inthyroid tissue will increase, and thyroid follicular epithelial cells will been observedmuch change under electron microscopy.