RESUMO
Objective:To evaluate the role of the autophagy in hydrogen-induced reduction of myocardial injury in septic mice.Methods:A total of 192 clean-grade healthy male C57BL/6J mice, aged 6-8 weeks, weighing 20-25 g, were divided into 6 groups ( n=32 each) using a random number table method: sham operation group (group Sham), sham operation plus hydrogen group (group Sham+ H 2), sepsis group (group S), sepsis plus hydrogen group (group S+ H 2), sepsis plus bafilomycin A1 group (group S+ BafA1) and sepsis plus hydrogen plus bafilomycin A1 group (group S+ H 2+ BafA1). Sepsis was produced by cecal ligation and puncture (CLP) after anesthesia. The mice inhaled 2% hydrogen for 1 h starting from 1 and 6 h after operation in group Sham+ H 2, group S+ H 2 and group S+ H 2+ BafA1. Bafilomycin A1 1 mg/kg was intraperitoneally injected at 1 h after operation in S+ BafA1 and S+ H 2+ BafA1 groups. Twenty mice in each group were selected to record the 7-day survival rates after operation. Then the mice were sacrificed at 24 h after operation to observe the pathological changes of myocardial tissues which were scored and detect the serum cardiac troponin I (cTnI) concentration (by enzyme-linked immunosorbent assay) and determine the level of microtubule-associated protein 1 light chain 3 B (LC3B) and P62 (by Western blot). LC3Ⅱ/LC3Ⅰratio was calculated. Results:Compared with group Sham, the 7-day survival rate after operation was significantly decreased, the serum cTnI concentrations and pathological scores of myocardial tissues were increased, the expression of P62 was up-regulated ( P<0.05), no significant change was found in LC3Ⅱ/LC3Ⅰratio ( P>0.05), and no significant change was found in the parameters mentioned above in group Sham+ H 2 ( P>0.05). Compared with group S, the 7-day survival rate after operation was significantly increased, the serum cTnI concentrations and pathological scores of myocardial tissues were decreased, LC3Ⅱ/LC3Ⅰratio was increased, and the expression of P62 was down-regulated in group S+ H 2, and LC3Ⅱ/LC3Ⅰratio was significantly decreased, and the expression of P62 was up-regulated in group S+ BafA1 ( P<0.05). Compared with group S+ H 2, the 7-day survival rate was significantly decreased, the serum cTnI concentrations and pathological scores of myocardial tissues were increased, LC3Ⅱ/LC3Ⅰratio was decreased, and the expression of P62 was up-regulated in group Sham+ H 2 ( P<0.05). Conclusions:The mechanism by which hydrogen alleviates myocardial damage may be related to promoting autophagy in septic mice.