脓毒症大鼠肠黏膜免疫屏障功能的变化

目的 研究脓毒症对大鼠肠黏膜免疫屏障功能的影响.方法 60只SD大鼠随机(随机数字法)分为对照组(n=15)和脓毒症组(n=45),采用盲肠结扎穿孔术(CLP)建立脓毒症模型.模型建立后3 h、6 h和12 h留取回肠黏膜和全血标本.分别进行肠黏膜形态学观察、肠防御素5(RD-5)及肠三叶因子3(TFF_3)Mrna表达水平检测、肠黏膜淋巴细胞凋亡分析,以及外周血中肠源性细菌DNA定性检测.结果 CLP所致脓毒症导致大鼠回肠黏膜明显损害,主要表现为上皮脱落、固有层分离、毛细血管出血和溃疡形成;脓毒症组模型建立后3 h即出现RD-5和TFF_3 Mrna表达显著性减少(与正常组比较,P<0.05),且6 h和12 h组进行下降(与3 h组比较,P<0.05),肠黏膜淋巴细胞凋亡数亦显著增加(P<0.05);同时,脓毒症组全血肠源性细菌DNA扩增全部阳性.结论 脓毒症时大鼠肠黏膜免疫屏障功能显著减退,且随脓毒症的发展而进行性恶化.

Alteration of immunological barrier of intestine mucosa in rats with sepsis

Objective To investigate immunological dysfunction of intestine mucosa barrier in a rat model of sepsis. Method Sixty Sprague-Dawley rats were assigned randomly(random number) into sepsis group (n = 45)and control group (n = 15). The animals in sepsis group were subjected to cecal ligation and puncture (CLP), whereas rats of control group underwent a sham surgery. The ileac mucosa and segments were harvested 3 h, 6 h and 12 hours after CLP, and the blood samples were collected. Pathological changes, protein levels of defensin-5 (RD-5) and trefoil factor-3(TFF_3) mRNA, lymphocytes apoptosis in the intestinal mucosa were determined. In an additional experiment, the gut-origin bacterial DNA in blood was detected. Results In the septic animals, in-testinal mucosa showed marked injury with loss of ileal villi, desquamation of epithelium, detachment of the lamina propria, hemorrhage and ulceration. Compared with control, the expression of TFF_3 mRNA and level of RD-5 pro-tein were decreased and the mucosal lymphocyte apoptosis increased (P < 0.05) in sepsis group. Compared with control group, the significant differences in RD-5 and TFF_3 mRNA appeared 3 hours after CLP and those differ-ences were progressively increased in 6 hours and 12 hours after CLP in sepsis group (P < 0.05, F of RD-5 = 11. 76, F of TFF_3 = 16.86 and F of apoptosis = 122.52). In addition, the gut-origin bacterial DNA in plasma de-tected was positive in all sepsis animals. Conclusions It suggests that immunological function of intestinal mucosa is impaired in septic rats and further worsened following the course of sepsis.