Influence Of Thymopentin Resuscitating Traumatic Hemorrhagic Shock On T-lymphocyte Subpopulation And Intestinal Mucosal Barrier In Rats

Objective:To explore the influence and mechanism of lactated Ringer's solution ( LRS ) and thymopentin (TP-5) resuscitating traumatic- hemorrhagic shock on DAO,ET in blood and T-lymphocyte subpopulation, and to investigate the influence of thymopentin(TP-5) on treating traumatic- hemorrhagic shock in rats.Methods:70 male SD rats were randomly divided into sham shock group (SS group, n=10), lactated Ringer's group (LRS group, n=30), and thymopentin (TP-5) group (LRS+TP group, n=30). Blood and tissue samples were taken at 12, 24, 48 hours after shock in LRS and LRS+TP groups respectively (n=10).After traumatic hemorrhagic shock was induced, the rats were received shed blood volume and two times of the shed blood volume of lactated Ringer's solution in LRS group in 30 minutes.In LRS+TP group, rats were resuscitated with shed blood volume and lactated Ringers solution in 30 minutes with two times the shed blood volume and followed by addition of thymopentin (The rats were injected with TP-5 0.3mg/kg/d on post-model). 1.5ml blood plasma was taken for determining the subsets of T-lymphocyte by FCM. The levels of DAO and ET were determined by ELISA method at each time point in both groups, and the morphologic changes of small intestine were examined under light microscope.Results:1. T-lymphocyte subpopulation: The expression of CD⁴⁺ and CD⁴⁺/CD⁸⁺ ratio decreased obviously at all time points; the values of CD⁸⁺ expression were higher in LRS group than those in SS group (P< 0.05). Compared with LRS group, the expression of CD⁴⁺ and CD⁴⁺/CD⁸⁺ ratio increased while the expression of CD⁸⁺ decreased significantly (P<0.05) in LRS+TP group at 24 and 48hr after treatment.2. DAO: Both resuscitation groups showed the significantly higher activities of DAO than that of SS group at all time points (P<0.05). The concentration of DAO reached the peak value at 24 hr, then begun to fall in LRS group; however it begun to fall significantly at 24 hr in LRS +TP group. The concentrations of DAO were lower in LRS+TP group than those in LRS group at 24 and 48 hr (P<0.05).3. ET: Both resuscitation groups showed the significantly higher activities of ET than those of SS group at all time points (P<0.05). The concentrations of ET reached the peak value at 24 h, then begun to fall in LRS group, while in LRS +TP group, the activities of DAO in blood plasma were significantly decreased at 24h and 48 h. The concentrations of ET were lower in LRS+TP group than those in LRS group at 24 and 48 hr (P<0.05).4. Pathological changes and morphometric assessment: The structural barrier of intestinal mucous was not repaired thoroughly in both resuscitating groups. The intestinal mucous pathological changes were lighter in LRS+TP group than those in LRS group. In two resuscitating groups, the height and thickness of mucosal villa were descended compared with those of the SS group, while the height and thickness of villa were less changed in LRS+TP group than those in LRS group at 24h and 48h (P <0.05).Conclusion:1. The model of traumatic-hemorrhagic shock in rats is established successfully, with satisfying availability, controllability, and repeatability.2. Thymopentin (TP-5) may increase the expression of CD⁴⁺ and maintain the normal ratio of CD⁴⁺/CD⁸⁺. The application of thymopentin (TP-5) may improve and stabilize cellular immune function.3. Compared with LRS group, LRS+TP group show the use of hymopentin (TP-5) may improve the local cellular immune function of gut and reduce the injury of gut and protect intestinal mucosal barrier.4. Although Thymopentin(TP-5) may improve cellular immune function and protect intestinal mucosal barrier, there is no significant elevation of survival rate in rats. Further study will be necessary to explore the mechanism of the influence of Thymopentin(TP-5) on trauma shock.