Expression Of BECN1,LC3 And P62 In Rat Muscle Tissues After Ante-Mortem And Postmortem Injury

Objective:In this study,the expression of autophagy-related proteins BECN1,LC3 and p62 in rats post-injuried muscle tissue were compared with those of the intact muscle tissues and postmortem injury,to explore whether autophagy can be used as a vital reaction to distinguish ante-mortem and postmortem injury.Methods:A model of right hind limb of rats injured was prepared.12 healthy Sprague-Dewley rats were randomly divided into the intact control group and the ante-mortem injury groups(at 2h,8h and 24h post-injury).The skeletal muscle samples of 12 rats were collected to detect of the level of autophagic proteins by immunofluorescence technology.Then,72 rats were randomly divided into the intact control group,the ante-mortem injury groups(at 0.5h,1h,2h,4h,8h,16h and 24h post-injury),and postmortem injury groups(at 0.5h,1h,2h and 4h post-injury).The skeletal muscle samples of 72 rats were collected to distinguish ante-mortem and postmortem injuries by western blotting.The skeletal muscle samples in the control group were collected at postmortem interval 0-9 days.Results:The results of double immunofluorescence showed that the proteins BECN1,LC3and p62 in the injured skeletal muscle of rats were increased;the mean fluorescence intensity of BECN1 and p62 was the highest at 8h post-injury,and LC3 reached the maximum at 2h.The results of Western blotting showed that the expression of BECN1and the ratio of LC3-?/LC3-?in ante-mortem group showed an up-down-up regulation.Compared with the control group,the expression level of BECN1 protein increased at 0.5h post-injury,and the ratio of LC3-?/LC3-?increased at 1 h.There was no significant difference of the expression of BECN1 and the ratio of LC3-?/LC3-?in the postmortem injury group and the control group.The expression of protein p62 was not affected by injury,either ante-mortem injury or postmortem injury.The expression levels of BECN1 and the ratio of LC3-?/LC3-?centralized and standard were distinguished ante-mortem from postmortem injury groups.The principal components extracted from OPLS-DA had a better interpretation of the identification model(R~2X=0.563,R~2Y=0.439),but it is less predictive of the model(Q~2=0.366).BECN1,p62 and LC3could still be detected 9 days after rat death.Conclusion:Autophagy in skeletal muscle of rats can be induced by mechanical injury,and the expression of BECN1 and LC3 is time-ordered.The expression of BECN1,in particular,was increased at 0.5h post-injury by western blotting,which may provide a possibility to identify the cases with short survival time after injury.Autophagic proteins BECN1 and LC3 are expected to be markers to differentiate between ante-mortem injury and postmortem injury.