Role Of High Mobility Group Box-1 Protein In Lung Injury Induced By Post-hemorrhagic Shock Mesenteric Lymph

Objective: High mobility group box-1 protein(HMGB1)plays an important role of multiple pathogenic factors-induced acute lung injury(ALI).Post-hemorahgic shock mesenteric lymph(PHSML)return is an important mechanism by which hemorrhagic shock-induced ALI.However,the mechanism by which PHSML blockage alleviating ALI needs further investigation.Therefore,based on the establishment of mouse' model of hemorrhagic shock,the present study observed the effects of PHSML drainage on the mRNA expressions and protein levels of HMGB1 and receptor for advanced glycation end products(RAGE)in mouse lung following hemorrhagic shock.Meanwhile,we compared the levels of HMGB1 and RAGE between the normal mesenteric lymph(NML)and PHSML.Furthermore,the PHSML was injected intravenously to normal mice for the observation of HMGB1 and RAGE contents in lung tissue.In conclusion,the role of HMGB1 in PHSML reducing ALI was revealed.Methods: Male C57BL/6J mice were randomized to sham,hemorrhagic shock(shock),hemorrhagic shock plus mesenteric lymph drainage(shock+drainage)group,n=6 each group.In the shock,shock+drainage groups,the mice received hemorrhage from the right femoral artery with an even speed.The arterial blood pressure(MAP)was reduced to 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 through right femoral artery within 30 min.In the shock+drainage group,the mesenteric lymph duct was cannulated and PHSML was drained up to 3 h after resuscitation.In the sham group,the mice were anesthetized,cannulated and operated as described above,but no blood was withdrawn or infused.At 3h after infusion or at corresponding time point in each group,lung tissuesfrom a fixed location were harvested.Part of tissue from each mouse was used for the mRNA of HMGB1 and RAGE determination using qRT-PCR method and part of the remainder lung were used for the measurement of HMGB1,RAGE by ELISA method.In addition,the NML was drained from 18 male normal mice after anesthesia for 1 hour,meanwhile,the PHSML was drained from six mice following hemorrhagic shock and fluid resuscitation from 0 to 3h.The levels of HMGB1 and RAGE in lymph were detected with the method of ELISA.Lastly,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 lung tissues were harvested for the determination of HMGB1 and RAGE with the method of ELISA.Results: The mRNA expressions and protein levels of HMGB1 and RAGE in the pulmonary tissue of shocked mice were remarkable increased compared to the sham group(P<0.05).PHSML drainage decreased the mRNA expressions and protein levels of HMGB1 and RAGE in the pulmonary tissue of shocked mice(P<0.05),have no statistics different compared with the sham group(P>0.05).Meanwhile,there was no statistics different in HMGB1 and RAGE protein levels between the NML and PHSML(P>0.05).Intravenous infusion of PHSML increased the HMGB1 level in the pulmonary tissue of normal mice,which was eliminated by GL treatment(P<0.05).The changes of RAGE in each group were similar,however,there was on statistics different among the four groups(P>0.05).Conclusion: These current results in this study demonstrated that HM GB1 play role in PHSML inducing lung injury subjected to hemorrhagic shock,which is related to the RAGE.