体外循环早期小肠粘膜细胞凋亡的实验研究

目的探讨体外循环(cardiopulmonarybypass,CPB)早期大鼠小肠粘膜上皮细胞凋亡规律及其意义。方法建立大鼠CPB模型。分别对CPB组、假手术组(shamoperation,SH)和正常组(normal,N)大鼠于术后3h、6h、12h和24h取回肠末端粘膜进行光镜、电镜观察,并用TUNEL方法研究肠上皮细胞凋亡。结果HE染色CPB组见较多的凋亡细胞分布于小肠黏膜上皮层;CPB后24h有少数的肠粘膜断裂;所有切片未见明显的炎症及坏死现象。电镜显示凋亡小体形成。TUNEL法见大量呈棕褐色的阳性细胞核,分布位置同HE染色。CPB后3h粘膜上皮细胞凋亡数较对照组明显增高(P<0.01),CPB后6h达到峰值。结论CPB早期大鼠肠粘膜上皮细胞出现大量凋亡,这些变化可能是CPB后肠道细菌及内毒素易位的细胞学基础。

An Experimental Study on the Apoptosis of Intestinal Mucosa Cells During Early Stage After Cardiopulmonary Bypass

OBJECTIVE To explore the significance of apoptosis of intestinal mucosa cells during early stage after cardiopulmonary bypass in rats.METHODS The CPB model in rats was established according to the reference. Distal Ileum mucosal tissues were studied under microscope and electron microscope after 3h, 6h, 12h and 24h of operation in sham operation rats and CPB rats, respectively. Apoptosis index of gut mucosal epithelial cells was analyzed with terminal deoxynucleotidyl - transferase mediated dUTP - biotin nick end labeling (TUNEL) method. RESULTS HE staining revealed that there were relatively abundant apoptotic cells in mucosal epithelial layer, especially at the top of villus, in all CPB groups. There were Some disruptions of intestinal mucosa in 24h after CPB group. But no obvious inflammatory reaction and signs of necrosis were observed in all the slides. Apoptotic body formation could be identified by EM. Large numbers of brown positive nuclei were revealed by TUNEL method with their distribution as similar to that found by HE staining. When comparing with those in control group, the apoptotic cells were increased significantly (P<0.01) in 3h after CPB group, and peaked in 6h after CPB group.CONCLUSION There was a large number of apoptotic cells in rats intestinal mucosal epithelium in early stage after CPB. These changes might be the cellular basis of intestinal translocation of bacteria and endotoxin.