Stellate Ganglion Blockade Abolishes Hemorrhagic Shock-induced Intestinal Musosal Barrier Dysfunction Through Suppression Of Endoplasmic Reticulum Stress

More and more scholars realize that intestinal injury and dysfunction are closely related to the occurrence and development of traumatic hemorrhagic shock.Intestinal barrier plays an important role in maintaining the stability of intestinal environment,which depends on its interaction with intestinal microorganisms and immune response.Intestinal barrier dysfunction can lead to the translocation of intestinal pathogens which is a key factor resulting in multiple organ dysfunction syndrome(MODS).Therefore,the development of new clinical therapy to improve intestinal barrier function has potential application value in the treatment of MODS induced by traumatic hemorrhagic shock.Stellate ganglion block(SGB)is a widely method of local anesthesia in clinic,which can regulate the functions of autonomic nervous system,endocrine system and immune system.Our previous study found that SGB can improve intestinal injury by reducing the over activation of sympathetic nerve after hemorrhagic shock.Hemorrhagic shock leads to endoplasmic reticulum stress(ERS)in parenchymal cells,and then leads to all organs damage.However,it is not clear whether ERS is involved in SGB improving intestinal injury after hemorrhagic shock.Therefore,in this study,we hypothesized that the improvement of SGB on intestinal function after hemorrhagic shock is mediated by inhibition of ERS,thus revealing the beneficial mechanism of SGB on ERS.Healthy male Wistar rats weighing(300±20)g were used in this study.All animals were randomly divided into six groups,as follows: Sham,Shock,Sham+SGB,Shock+SGB,Shock + ERS inhibitor 4-PBA(Shock+4-PBA),Shock+SGB+ERS agonist Tunicamycin(Shock+SGB+TM),with six rats in each group.According to the experimental design,the rats in three groups of Sham+SGB,Shock+SGB and Shock+SGB+TM were treated with SGB(0.2 m L of 0.25% ropivacaine hydrochloride was injected into stellate ganglion via skin of body surface symbol,and positive Horner’ syndrome was observed and regarded as SGB achieved),and the rats in Sham,Shock and Shock+4-PBA were not treated with SGB(the same amount of 0.9% physiological saline was injected into stellate ganglion via skin of body surface symbol).After then,a conscious rat model of hemorrhagic shock(40 ±2 mm Hg for 1 hour,followed by resuscitation)was employed in Shock,Shock+4-PBA,Shock+SGB and Shock+SGB+TM groups;fluid resuscitation was performed accompanied by administrations of 4-PBA,TM or vehicle,respectively;the other two groups were performed exactly the same operation as the rats in the Shock group,but without bloodletting or fluid resuscitation.Blood samples of inferior vena cava were collected at 3 h or equal time after fluid resuscitation,and the indices of intestinal permeability,D-lactic acid(D-LA)and intestinal fatty acid binding protein(I-FABP)in plasma were used to detect the changes of intestinal permeability.At the same time,15 cm upward from the ileocecum,a segment of ileum was taken and FITC-dextran4(FD4,25 mg/m L)was injected into the intestinal sac by the method of intestinal sac valgus.The concentration of FD4 in the intestinal sac was calculated and the intestinal permeability index(IPI)was calculated.In addition,the gut was collected for the assay of morphological feature(HE staining),the wet / dry ratio(W/D),and the expressions of initiator molecules activating transcription factor 6α(ATF6α),inositol-requiring ER-to-nucleus signal kinase 1α(IRE1α)and protein kinase RNA-like ER kinase(PERK)in three different signal pathways of ERS using the method of Western blotting.The results showed that hemorrhagic shock induced intestinal histological damages,enhanced the intestinal permeability and increased ERS.These are shown as follows,intestinal histological injury: W/D in intestinal tissue was increased,while the height of intestinal villi,the thickness of submucosa and the thickness of muscular layer were decreased;Changes of intestinal permeability: the plasma D-LA and I-FABP and intestinal tissue FD4 were increased;The changes of the starting protein molecules of the three ERS signaling pathways: the expression of ATF6 α,IRE1 α and PERK were increased.Either SGB or 4-PBA treatments alleviated these adverse effects of hemorrhagic shock.Whereas,TM administration abolished the beneficial effect of SGB on these indices in rats following hemorrhagic shock.In summary,both SGB and ERS inhibitor reduced intestinal injury,decreased intestinal permeability and down-regulated the expression of ERS initiation protein molecules of ATF6 α,IRE1 α and PERK in rats following hemorrhagic shock,while TM administration abolished the beneficial effect of SGB in rats following hemorrhagic shock.These data prove that the SGB alleviates hemorrhagic shock-induced intestinal mucosal barrier dysfunction through suppression of ERS.On the basis of enriching the mechanism of SGB,the results provide new experimental data for determining the prevention and treatment of severe hemorrhagic shock and expanding the scope of application of SGB.