Liu Ji-chun, Wan Li, He Ming, Cheng Xiao-shu
Department of Cardiovascular Surgery, First Affiliated Hospital of Nanchang University, Nanchang 330006, China.
Zhonghua Yi Xue Za Zhi. 2007 Dec 25;87(48):3436-9.
To study the protective role of heat shock protein (HSP)70 expression in the myocardial cells undergoing anoxia/reoxygeneration.
Myocardiocytes of neonatal SD rats were cultured and randomly divided into 4 groups: anoxia/reperfusion (A/R) group undergoing anoxia/reperfusion; A/R + HS group, undergoing transfection of HS and A/R, pCDNA HSP70 + A/R group, undergoing transfection of liposome-coated HSP70 pCDNA and A/R, and control group. RT-PCR and Western blotting were used to detect the mRNA and protein expression of HSP70 in the cells. The cell viability was examined by MTT method. The levels of lactic dehydrogenase (LDH), and serum creatine phosphokinase isoenzyme (CPK) were detected. Transmission electronic microscopy was used to observe the ultrastructure of the cells. Apoptosis rate was measured.
The cell viability rates of the HS + A/R group and pCDNA HSP70 + A/R group were (71.8 +/- 10.3)% and (73.4 +/- 12.2)% respectively, both significantly higher than that of the A/R group [(35.2 +/- 6.8)%, both P < 0.01]. The LDH activity levels of the HS + A/R and pCDNA HSP70 + A/R groups were (14.3 +/- 2.6) and (14. 6 +/- 2.9) IU/L respectively, both significantly lower than that of the A/R group [22.9 +/- 4.0 IU/L, P < 0.01]. The cell ultrastructure was abnormal in the A/R group e, whereas nearly normal in the HS + A/R and pCDNA HSP70 + A/R groups. The HSP70 mRNA land protein were only slightly expressed in the myocardiocytes of the A/R group; However, the expressions of HSP70 mRNA and protein were of the HS + A/R and pCDNA HSP70 + A/R groups were significantly higher than those of the A/R group (both P < 0.01). The apoptosis rates of the A/R group was (12.84 +/- 2.17), significantly higher than that of the control group [(2.16 +/- 0.15), P < 0.01], and the apoptotic rates of the HS + A/R and pCDNA HSP70 + A/R groups were (5.23 +/- 1.04) and (4.42 +/- 0.93) respectively, both significantly lower than that of the A/R group (P < 0.01).
Overexpression of HSP70 alone can provide protection, related to the anti-apoptosis effect, for cardiomyocytes against anoxia-reoxygeneration.
研究热休克蛋白（HSP）70表达在经历缺氧/复氧的心肌细胞中的保护作用。
培养新生SD大鼠的心肌细胞并随机分为4组：经历缺氧/复氧的缺氧/再灌注（A/R）组；经历HS转染及缺氧/复氧的A/R + HS组，经历脂质体包裹的HSP70 pCDNA转染及缺氧/复氧的pCDNA HSP70 + A/R组，以及对照组。采用RT-PCR和蛋白质印迹法检测细胞中HSP70的mRNA和蛋白表达。通过MTT法检测细胞活力。检测乳酸脱氢酶（LDH）和血清肌酸磷酸激酶同工酶（CPK）水平。使用透射电子显微镜观察细胞超微结构。测量凋亡率。
HS + A/R组和pCDNA HSP70 + A/R组的细胞活力率分别为（71.8±10.3）%和（73.4±12.2）%，均显著高于A/R组[（35.2±6.8）%，P均<0.01]。HS + A/R组和pCDNA HSP70 + A/R组的LDH活性水平分别为（14.3±2.6）和（14.6±2.9）IU/L，均显著低于A/R组[22.9±4.0 IU/L，P<0.01]。A/R组细胞超微结构异常，而HS + A/R组和pCDNA HSP70 + A/R组接近正常。HSP70 mRNA和蛋白在A/R组心肌细胞中仅轻微表达；然而，HS + A/R组和pCDNA HSP70 + A/R组的HSP70 mRNA和蛋白表达均显著高于A/R组（P均<0.01）。A/R组的凋亡率为（12.84±2.17），显著高于对照组[（2.16±0.15），P<0.01]，HS + A/R组和pCDNA HSP70 + A/R组的凋亡率分别为（5.23±1.04）和（4.42±0.93），均显著低于A/R组（P<0.01）。
单独过表达HSP70可通过抗凋亡作用为心肌细胞提供针对缺氧-复氧的保护。
