Effects of beating heart on endoplasmic reticulum stress and myocardial apoptosis in patients with mitral valve replacement

Abstract

Objective To explore the effects of beating heart on endoplasmic reticulum stress(ERS) and myocardial apoptosis in patients with mitral valve replacement(MVR). Methods A total of 80 patients with rheumatic heart disease and mitral valve stenosis, all genders, aged 38 to 59 years old, weighed 43 to 73 kg, with American Society of Anesthesiologists(ASA) physical status classification Ⅱ-Ⅲ and scheduled for MVR, were randomly divided into beating heart group(BH group, n=40) and cardiac arrest group(CA group, n=40). Radial artery blood was collected to determine the concentration of plasma creatine kinase-MB(CK-MB) and cardiac troponin T(cTnT) by enzyme-linked immunosorbent assay(ELISA) at the start of opening the right atrium(T0), 30 minutes after aortic cross-clamping[30 minutes after cardiopulmonary bypass(CPB) in BH group, T1] and when stitched right atrium(T2), respectively. Right auricle tissue was collected at T0 and T2, respectively, and the mRNA expression of glucose regulated protein 78(GRP78), CCAAT/enhancer-binding protein homologous protein(CHOP) and c-Jun amino-terminal kinase(JNK) or the protein expression of GRP78, CHOP and p-JNK in cardiac muscle tissue were detected by reverse transcription-polymerase chain reaction(RT-PCR) or Western blot, respectively. The apoptosis of cardiomyocytes was determined by terminal deoxynucleotidy transferase-mediated dUTP nick-end labeling(TUNEL) method. Results Compared with CA group at the same time point, the concentrations of plasma CK-MB and cTnT at T1 and T2 and the rate of myocardial cell apoptosis at T2 were all lower(P<0.05) in BH group. The mRNA expression of GRP78, CHOP and JNK in cardiac muscle tissue in BH group were all lower(P<0.05) than those in CA group at T1 and T2, and the protein expression of GRP78, CHOP and p-JNK in cardiac muscle tissue in BH group were all lower(P<0.05) than those in CA group at T1 and T2. Conclusion Beating heart surgery can alleviate ERS, reduce myocardial apoptosis, and thus relieve myocardial injury in patients undergoing MVR. Key words: Cardiopulmonary bypass; Heart valve prosthesis; Endoplasmic reticulum; Stress; Apoptosis