影响脓毒症受损肠黏膜修复的机制

目的 探讨影响脓毒症肠黏膜损害后修复的因素。方法 采用肓肠结扎穿孔(CLP)所致脓毒症模型，分别以CLP后6，24，48 h不同时间段观测肠黏膜损伤程度和修复过程，前者包括形态学观察及细胞凋亡的测定，后者包括肠黏膜修复的杯状细胞变化、黏膜肠三叶因子3(TFF3)、转化生长因子β1(TGF-β1)以及TNF-α、IL-1含量。结果 形态学观察显示肠黏膜呈持续损害状态，6h的损害积分明显小于24h，48 h组(P＜0.05)，后两组之间差异无统计学意义(P＞0.05)；磷酸化caspase-3蛋白在3组均高于sham组4倍以上；黏膜IL-1，TNF-α含量明显高于sham组3～4倍，其中24h及48 h组明显高于6h组。肠黏膜的修复过程不明显，损伤黏膜未见到明显的杯状细胞积聚；TFF3在6h组轻度增高，24h及48 h组表达下降；杯状细胞数量在CLP的3个组明显减少；TGF-β1在6h组增高，其他两组均接近于sham组。结论 严重脓毒症肠黏膜持续的高炎症状态、杯状细胞功能以及黏膜重建能力下降，影响了受损肠屏障的修复。

The mechanism of damaged intestinal mucosal repair in a mouse model of sepsis

Objective To investigate the unfavorable factors of intestinal mucosa repair after the intestinal epithelial injury in vivo in a mouse model of sepsis. Methods The method of cecal ligature and puncture (CLP) was used to induce sepsis and then the intestinal mucosa damage, epithelial cell apoptosis and the number of transformed goblet cells were observed, and the concentrations of serum TNF-αt, IL-1 and TGF-β1 and TFF3 ( trefoil factor 3) in small intestinal mucosa were determined. All above various laboratory examinations were made by different assays including H-E staining, western blot, ELISA and immunohistochemistry respectively. The experimental mice were divided into sepsis group and sham operation control group. The mice with sepsis were separately sacrificed 6 hours ( n = 7 ), 24 hours ( n = 7) and 48 hours ( n = 7) after CLP. Results In septic mice group, the injured intestinal mucosa was found 6 hours after CLP. The damage scores in mice 24 h and 48 h after CLP were higher than those 6 h after CLP, but there was no significant difference between those 24 h and 48 h after CLP. Moreover, a few goblet cells or other epithelial cells adjacent to the injured surface migrated onto the wound to cover the denuded area. The number of goblet cells was substantially decreased in mice of sepsis group 6 hours after CLP compared with sham operation control group. Compared with sham operation control group, levels of IL-1 and TNF-α significantly increased 3-4 times in mice of sepsis group at all intervals, and the phosphorylated caspase-3 increased 4 times. Although TFF3 assayed by using Western blot showed modest increase 6 h after CLP and it declined 24 h and 48 h later. A similar change was found in TGF-β1, it modestly increased 6h after CLP, but it didn't elevate 24 h and 48 h later. Conclusions Severe sepsis keeps on the inflammatory reaction and epithelial cell apoptosis, preventing the repair of intestinal mucosa from injury.