腺苷对缺氧/复氧心肌细胞的保护作用

Adenosine protects cardiomyocytes from hypoxia/reoxygenation injury

本研究旨在探讨腺苷 (adenosine ,ADO)对缺氧 /复氧 (hypoxia/reoxygenation ,H/R)心肌细胞的保护作用及其分子机制。将原代培养的新生大鼠心肌细胞分成H/R对照组和ADO (1 0 μmol/L)保护组。用倒置相差显微镜观察心肌细胞的生长状态。检测两组培养基质乳酸脱氢酶 (LDH)活性和心肌细胞Ca2 + 和丙二醛 (MDA)浓度。用ELISA法检测肿瘤坏死因子 (TNF α)的表达 ,并用凝胶电泳迁移率改变法 (EMSA)测定核因子 (NF κB)结合活性。所得结果如下 :(1)心肌细胞H/R培养后皱缩、变圆 ,伪足减少 ,ADO组心肌细胞的形态变化小于对照组 ;(2 )ADO减少缺氧和复氧期间心肌细胞LDH的漏出 (bothP <0 0 1) ;(3 )ADO降低缺氧和复氧期间心肌细胞内的Ca2 +浓度 (bothP <0 0 1) ;(4)ADO降低缺氧和复氧期间心肌细胞MDA浓度 (bothP <0 0 1) ;(5 )ADO抑制缺氧和复氧期间TNF α的表达 (bothP <0 0 1) ;(6)ADO抑制缺氧和复氧期间心肌细胞NF κB结合活性 (bothP <0 0 1)。以上结果提示 :(1)外源性ADO可减轻心肌细胞的H/R损伤 ;(2 )外源性ADO抑制H/R期间心肌细胞TNF α的表达 ;(3 )外源性ADO可能通过抑制心肌细胞NF κB结合活性下调TNF

The aim of this study was to investigate the protective effect of adenosine (ADO) on cardiomyocytes following hypoxia/reoxygenation (H/R) and its molecular mechanism. Primary cultured cardiomyocytes of neonatal rats were divided into two groups, namely H/R (control) and ADO (1 0 μmol/L) groups. The morphologic changes in cardiomyocytes were observed under an inverted phase contrast microscope. The following parameters of the two groups were determined: lactate dehydrogenase (LDH) activity, intracellular calcium concentration and malondialdehyde (MDA) content. Tumor necrotic factor (TNF α) assay was performed using an ELISA kit and NF κB in the nucleus was analyzed by electrophoretic mobility shift assay (EMSA). The results are as follows: (1) after H/R injury, cardiomyocytes contracted, tending to get round in shape and its pseudopods decreased, while marked morphological changes were not observed in ADO group; (2) LDH leakage maintained at a lower level in ADO group than that in the control group during H/R (both P < 0 01); (3) ADO significantly reduced the concentration of calcium in cells and prevented calcium overload during H/R (both P < 0 01); (4) ADO markedly reduced the content of MDA during H/R (both P < 0 01); (5) ADO inhibited the production of TNF α during H/R (both P < 0 01); and (6) ADO down regulated NF κB binding activity of cardiomyocytes during H/R (both P < 0 01)?The results suggest that (1) exogenous ADO attenuates H/R injury of cultured cardiomyocytes; (2) exogenous ADO inhibits the production of TNF α after H/R injury; (3) exogenous ADO prevents the activation of NF κB, which may be the molecular mechanism of down regulation of TNF α expression.