Protective Effect Of Lower Thoracic Epidural Blockade On Intestinal Epithelial Barrier In Rats With Hemorrhagic Shock And Resuscitation

Objective: To investigate the effects of lower thoracic epidural blockade(LTEB)on intestinal epithelial barrier(IEB)impaired by hemorrhagic shock and resuscitation(HSR)and the possible mechanism of protection in rats.Methods: Seventy-two Sprague-Dawley(SD)rats with epidural catheterization according to a modified method described by Bahar were randomly divided into four groups with 18 in each: sham group(group S),control group(group C),normal saline group(group N)and lower thoracic epidural blockade group(group T).In group S,rats were just received vascular cannulation,whereas the rats in other groups were subjected to hemorrhagic shock and resuscitation with normal saline according to the modified method described by Wiggers.Thirty minutes before bleeding,either 0.075%ropivacaine(group T)or normal saline(group N)100 μl/kg was infused through thoracic epidural catheters.The survival rates of rats in 72 h after resuscitation were evaluated.The mean arterial pressure(MAP)and heart rate(HR)were monitored after vascular cannulation(T0),30 min after epidural infusion(T1),30 min of shock(T2),60 min of shock(T3),30 min and 60 min after resuscitation(T4 and T5 respectively).Arterial blood samples were collected for blood gas analysis at T0,T3 and T5.At 3 h following resuscitation,the severity of intestinal edema,the pathological changes of intestinal mucosa and the function of IEB were evaluated by wet and dry ratio(W/D),Chiu’s score and lipopolysaccharide(LPS)concentrations in the portal vein,respectively.The expression of Occludin and glial fibrillary acidic protein(GFAP),a marker of enteric glial cells(EGCs),were determined by western blot.Results: Compared with group C and group N,the survival rates(group C vs.group N vs.group T: 0% vs.10% vs.30%)and median survival time(group C vs.group N vs.group T: 9 h vs.14 h vs.32 h)of group T were significantly promoted(P < 0.05);While MAP and HR decreased at T4 and T5,the levels of p H and lactic acid at T3 and T5 were alleviated(P < 0.05).Besides,in group T,the levels of W/D,Chiu’s score and LPS were decreased while the expression of Occludin and GFAP were increased significantly in comparison with group C and group N(P < 0.05).Conclusion: LTEB attenuates IEB impairment induced by HSR in rats,alleviating internal environment disturbance and thus promoting survival rates after resuscitation,whose mechanism is related with activation of EGCs.