Effect Of SPV On Morphological Changes Of Intestinal Mucosa In Traumatic-hemorrhagic Shock Rats

ObjectiveSevere trauma may bring about stress response of the body. The intestine is one of the most sensitive organs to ischemic injuries. Dysfunction of intestinal mucosal barrier may increase intestinal permeability, which results in the translocation of bacterial endotoxin from intestinal cavity into lymphatic and vascular systems. Intestine is a surgical stress central organ and the body's largest bacteria reservoir. Therefore, prevention and treatment of translocation of intestinal bacterial and endotoxin is the key issue on intestinal infection. The study utilized the rat model with severe traumatic-hemorrhagic shock and observed morphological changes of intestinal mucosa at different time points to explore the protective effect of SPV (Smecta, Polymyxin B, Vitamin B6) on intestinal mucosa.Methods128 male Sprague-Dawley(SD) rats (weighting250～300g) were randomly divided into 4 groups: control group (n=8); shock group (n=40); resuscitation group (n=40); SPV intervention group (n=40). The last three groups were subdivided into five subgroups (n=8) according to different time points after the shock. The traumatic hemorrhagic shock model was established by arterial bloodletting, femoral fracture and soft tissue injury. The shock resuscitation group was given with the rat's own blood and Ringer's solution intravenously. SPV intervention group was added with SPV compounds orally before the shock happened. Statistic mortality between experimental rats.Intestinal mucosal damage index were calculated and intestinal mucosal morphologic changes were observed by light microscope.ResultsThe mortality rate of experimental groups: The difference between control group and experimental groups were statistically significant (P < 0.05). The difference between shock recovery group,SPV intervention shock recovery group and shock group were statistically significant (P < 0.05),but the difference between shock recovery group and SPV intervention shock recovery group were statistically significant (P < 0.05).Intestinal mucosal damage index: Compare with control group, intestinal mucosal damage index increased significantly at all time points of the shock (p<0.01), and there were also significantly differences among the time points in three shock groups (p<0.01). There were less damage index at 16h after the shock than those at 1h in resuscitation group (p<0.01). There were less damage index at 4h, 8h,16h after the shock than those at 1h subgroup in SPV intervention group (p<0.01). The structure of intestinal mucosa was less damaged in resuscitation group and SPV intervention group than that in control group (p<0.01), with the lower damage index in SPV intervene group than that in resuscitation group (p<0.05).The height of intestinal mucosa villi: The intestinal mucosa villi was significantly shorted in all shock groups compare with control group (p<0.01), with the shortest at 8h, 16h after shock. There were severe mucosal edema in resuscitation group and SPV group compared with control group (p<0.01), with less mucosa edema in SPV group than resuscitation group (p<0.05).The thickness of intestinal mucosa villi: Compared with control group, the intestinal mucosal villi became thicker in all shock groups at all time points (p<0.01). There were less changes of villi thickness in SPV intervention group and resuscitation group than those of shock group at 1h, 2h subgroups, with significantly less changes at 4h subgroup (p<0.01). There was also significant difference in the thickness of intestinal mucosal villi between SPV group and resuscitation group (p<0.05).Conclusion(1) After severe trauma-hemorrhagic shock,intestinal mucosa is widely damaged with the shock prolonged. The pathological changes include mucosal villi disarranged, lacteals and vessels extended, red blood cell infiltrated or bleeding, degeneration and necrosis of epithelial cells, chyle tubal and vascular dilatation, and lamina propria naked and separated from epithelial layer, or villi broken. There are also edema, hemorrhage and cracking in muscularis mucosa. In the resuscitation process, the height and thickness of mucosal villi may be recovered, but submucosal or submucosal muscularis cavitations may remain for a short period.(2) The damage of intestinal mucosa caused by severe trauma– hemorrhagic shock happens obviously at 1h, 2h after shock, though the fluid resuscitation is applied effectively. Therefore the reperfusion injury of intestinal mucosa happens earlier and severer during traumatic hemorrhagic shock.(3) Earlier oral application of SPV may have beneficial effect on preventing intestinal mucosa damage, due to arresting translocation of intestinal bacterial and endotoxin.