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 (P0.01) 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.