| Background and objective: Excessive inflammatory response is one of mechanisms that severe hemorrhagic shock inducing acute kidney injury.Under the hemorrhagic shock conditions,the return of gut derived toxic substances contained mesenteric lymph to systemic circulation is a major contributor of organ injury.Mesenteric lymph drainage reduces morphological damages and function disorders of kidney insulted by hemorrhagic shock.However,the mechanism remains to be further investigated.Therefore,in the present study,our aim is to reveal the significance of the intestinal lymphatic pathway in the pathogenesis of kidney injury following hemorrhagic shock,after establish a mouse’ model of hemorrhagic shock,the effects of mesenteric lymph drainage on the mRNA expressions and protein levels of high mobility group box-1 protein(HMGB1)and receptor for advanced glycation end products(RAGE)and the mRNA expression of Nod-like receptor family,pyrin domain containing(NLRP)3inflammasome in renal tissue were observed.Furthermore,the post hemorrhagic shock mesenteric lymph(PHSML)was injected intravenously to normal mice for the observation of HMGB1 and RAGE contents in renal tissue.Methods: Eighteen male C57BL/6J mice were randomized to sham shock,hemorrhagic shock(shock),hemorrhagic shock+PHSML drainage(shock+drainage)group.In the shock,shock+drainage groups,hemorrhage was performed from the right femoral artery with an even speed for the reducation of the arterial blood pressure(MAP)at a level of 40±2 mmHg within 10 min and maintained at this level for 90 min.Then,the mice received fluid resuscitation with the shed blood and an equal volume of Ringer’s solution within 30 min through right femoral artery.The MAP was observedfor 3 h after the end of infusion.In the shock+drainage group,after resuscitation finished,the mesenteric lymph was drained up to 3 h after mesenteric lymph duct intubation.In the sham group,the rats were anesthetized,cannulated and operated as described above,but no hemorrhage and resuscitation.At 3 h after resuscitation or at corresponding time,kidneys were harvested from a fixed location in each mouse.Part of kidney from each rat was used for the determination of HMGB1,RAGE and NLRP3 mRNA expressions using q RT-PCR method and part of the remainder kidney were used for the measurement of HMGB1 and RAGE levels by ELISA method.In addition,the normal mesenteric lymph(NML)was drained from 6 normal mice after anesthesia for 1 hour,then,the NML and PHSML were injected intravenously to normal mice or pretreated mice with glycyrrhizin(GL),an inhibitor of HMGB1,n=6/group,respectively.After 3 h,the renal tissues were harvested for the determination of HMGB1 and RAGE.Results: The expression of mRNA of HMGB1,RAGE and NLRP3 and the levels of HMGB1 and RAGE in renal tissue in the shock group were significantly enhanced compared to the sham group(P<0.05).The expression of mRNA of HMGB1,RAGE and NLRP3 and the levels of HMGB1 and RAGE in the shock+drainage group were significantly reduced compared to the shock group(P<0.05),moreover,had no significant difference compared with those of the sham group(P>0.05).Intravenous infusion of PHSML increased the RAGE level in the renal tissue of normal mice(P<0.05),but has no significant effect on the HMGB1 level(P>0.05).GL treatment remarkably decreased the contents of HMGB1 and RAGE in renal tissue of normal mice(P<0.05).Conclusion: Hemorrhagic shock causes increase of HMGB1 and RAGE expression results in the increase of NLRP3,which involves in the development of kidney injury following hemorrhagic shock.Mesenteric lymph drainage reducing the expression of mRNA of HMGB1,RAGE and NLRP3 and the levels of HMGB1 and RAGE,PHSML increased the RAGE level in renal tissue,which may be one of the mechanisms by whichPHSML-mediated injury. |
