Effect of SR9009 on myocardial injury in endotoxemic mice / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of SR9009 on myocardial injury in endotoxemic mice.Methods:Eighteen SPF healthy male C57BL/6 mice, aged 5 weeks, weighing 21-24 g, were divided into 3 groups ( n=6 each) by the random number table method: control group (C group), endotoxemia group (lipopolysaccharide [LPS] group) and endotoxemia + SR9009 group (LPS+ SR group). SR9009 50 mg/kg was intraperitoneally injected at 4 00 p. m. in LPS+ SR group. The endotoxemic model was prepared by intraperitoneal injection of LPS 15 mg/kg at 10 a. m. on the second day in mice. The left ventricular function was monitored by echocardiography at 9 h after LPS injection. Blood samples were collected from the heart cavity under direct visualization for determination of the serum creatine kinase isoenzymes (CK-MB), lactic dehydrogenase (LDH) and cardiac troponin I (cTnI) levels by enzyme-linked immunosorbent assay. Myocardial tissues were obtained and stained with HE for microscopic examination of the pathological changes (with a light microscope) and for determination of the expression of Beclin1, P62 and microtubule-associated protein 1 light cain 3 (LC3) (by Western blot), and the ratio of LC3Ⅱ to LC3Ⅰ was calculated. Results:Compared with group C, the ejection fraction and short-axis fractional shortening were significantly decreased, the left ventricular end-diastolic internal diameter and left ventricular end-systolic internal diameter were shortened, the left ventricular end-diastolic posterior wall thickness and left ventricular end-systolic posterior wall thickness were decreased, serum CK-MB, LDH and cTnI levels were increased, P62 expression in myocardial tissues was down-regulated, Beclin1 expression was up-regulated, LC3Ⅱ/LC3Ⅰ ratio was increased ( P<0.05), and the pathological changes were found in myocardial tissues in group LPS. Compared with group LPS, the ejection fraction and short-axis fractional shortening were significantly increased, the left ventricular end-systolic internal diameter was shortened, and the left ventricular end-diastolic posterior wall thickness was decreased ( P<0.05), no significant change was found the left ventricular end-diastolic internal diameter and left ventricular posterior end-systolic wall thickness ( P>0.05), the serum CK-MB, LDH and cTnI levels were decreased, and P62 expression in myocardial tissues was up-regulated, Beclin1 expression was down-regulated, LC3Ⅱ/LC3Ⅰ ratio was decreased ( P<0.05), and the pathological changes in myocardial tissues were significantly attenuated in LPS+ SR group. Conclusions:SR9009 can alleviate myocardial injury in endotoxemic mice, and the mechanism may be related to inhibition of autophagy.