BACKGROUND:Emodin has a variety of pharmacological activities such as anti-inflammatory,anti-viral and anti-oxidative stress,and also has a certain protective effect on sepsis-induced myocardial injury,but its mechanism of action is still unclear.OBJECTIVE:To investigate whether emodin can improve myocardial injury in septic mice by promoting autophagy.METHODS:Thirty-two male Kunming mice were divided into sham operation group(n=4),sham operation+emodin group(n=4),model group(n=8),model+emodin group(n=8),and emodin+3-methyladenine group(n=8).The myocardial injury model of septic mice was constructed by cecal ligation and puncture.3-methyladenine(10 mg/kg)was injected intraperitoneally 1 hour before modeling.Emodin(20 mg/kg)was injected intraperitoneally 30 minutes before modeling,and the other groups were injected with the same amount of normal saline at the same time point.Blood and myocardial samples were collected from all mice 24 hours after surgery.ELISA was used to detect the levels of brain natriuretic peptide and cardiac troponin Ⅰ in serum.Western blot assay was used to detect the protein expression of LC3B,Beclin-1,and p62 in myocardial tissue.Hematoxylin-eosin staining was used to observe the pathological changes in myocardial tissue.Ultrasound was used to evaluate the cardiac function of mice.RESULTS AND CONCLUSION:(1)Compared with the sham operation group,there was no significant difference in the levels of serum brain natriuretic peptide,cardiac troponin Ⅰ,and the protein expression of myocardial autophagy proteins LC3Ⅱ/LC3Ⅰ and p62 in the sham operation+emodin group(P＞0.05).(2)Compared with the sham operation+emodin group,the levels of serum brain natriuretic peptide and cardiac troponin I were significantly increased in the model group(P＜0.05).Compared with the model group,the levels of serum brain natriuretic peptide and cardiac troponin I were decreased in the model+emodin group(P＜0.05).(3)Compared with the model group,the expression of LC3Ⅱ/LC3Ⅰ and Beclin-1 protein was increased and the expression of p62 protein was decreased in the myocardial tissue of the model+emodin group(P＜0.05).Compared with the model+emodin group,the expression of LC3Ⅱ/LC3Ⅰ and Beclin-1 protein decreased and the expression of p62 protein increased in the emodin+3-methyladenine group(P＜0.05).(4)The myocardial fibers in the sham operation group were normal,the myocardial fibers in the model group were disordered with a large number of inflammatory cell infiltration,the myocardial fibers in the model+emodin group were slightly disordered,and some vacuolar changes were observed.The myocardial fibers were disordered,and more inflammatory cell infiltration was observed in the emodin+3-methyladenine group.(5)Compared with the sham operation group,the left ventricular short axis shortening rate and left ventricular ejection fraction were decreased in the model group(P＜0.05).Compared with the model group,the left ventricular short axis shortening rate and left ventricular ejection fraction were increased in the model+emodin group(P＜0.05).Compared with the model+emodin group,the left ventricular ejection fraction of emodin+3-methyladenine group was decreased(P＜0.05),and the left ventricular short axis shortening rate was reduced but not statistically significant(P＞0.05).(6)The above results indicate that emodin pretreatment can improve myocardial injury and myocardial dysfunction in septic mice by promoting autophagy.

BACKGROUND:Emodin has a variety of pharmacological activities such as anti-inflammatory,anti-viral and anti-oxidative stress,and also has a certain protective effect on sepsis-induced myocardial injury,but its mechanism of action is still unclear.OBJECTIVE:To investigate whether emodin can improve myocardial injury in septic mice by promoting autophagy.METHODS:Thirty-two male Kunming mice were divided into sham operation group(n=4),sham operation+emodin group(n=4),model group(n=8),model+emodin group(n=8),and emodin+3-methyladenine group(n=8).The myocardial injury model of septic mice was constructed by cecal ligation and puncture.3-methyladenine(10 mg/kg)was injected intraperitoneally 1 hour before modeling.Emodin(20 mg/kg)was injected intraperitoneally 30 minutes before modeling,and the other groups were injected with the same amount of normal saline at the same time point.Blood and myocardial samples were collected from all mice 24 hours after surgery.ELISA was used to detect the levels of brain natriuretic peptide and cardiac troponin Ⅰ in serum.Western blot assay was used to detect the protein expression of LC3B,Beclin-1,and p62 in myocardial tissue.Hematoxylin-eosin staining was used to observe the pathological changes in myocardial tissue.Ultrasound was used to evaluate the cardiac function of mice.RESULTS AND CONCLUSION:(1)Compared with the sham operation group,there was no significant difference in the levels of serum brain natriuretic peptide,cardiac troponin Ⅰ,and the protein expression of myocardial autophagy proteins LC3Ⅱ/LC3Ⅰ and p62 in the sham operation+emodin group(P＞0.05).(2)Compared with the sham operation+emodin group,the levels of serum brain natriuretic peptide and cardiac troponin I were significantly increased in the model group(P＜0.05).Compared with the model group,the levels of serum brain natriuretic peptide and cardiac troponin I were decreased in the model+emodin group(P＜0.05).(3)Compared with the model group,the expression of LC3Ⅱ/LC3Ⅰ and Beclin-1 protein was increased and the expression of p62 protein was decreased in the myocardial tissue of the model+emodin group(P＜0.05).Compared with the model+emodin group,the expression of LC3Ⅱ/LC3Ⅰ and Beclin-1 protein decreased and the expression of p62 protein increased in the emodin+3-methyladenine group(P＜0.05).(4)The myocardial fibers in the sham operation group were normal,the myocardial fibers in the model group were disordered with a large number of inflammatory cell infiltration,the myocardial fibers in the model+emodin group were slightly disordered,and some vacuolar changes were observed.The myocardial fibers were disordered,and more inflammatory cell infiltration was observed in the emodin+3-methyladenine group.(5)Compared with the sham operation group,the left ventricular short axis shortening rate and left ventricular ejection fraction were decreased in the model group(P＜0.05).Compared with the model group,the left ventricular short axis shortening rate and left ventricular ejection fraction were increased in the model+emodin group(P＜0.05).Compared with the model+emodin group,the left ventricular ejection fraction of emodin+3-methyladenine group was decreased(P＜0.05),and the left ventricular short axis shortening rate was reduced but not statistically significant(P＞0.05).(6)The above results indicate that emodin pretreatment can improve myocardial injury and myocardial dysfunction in septic mice by promoting autophagy.