单纯缺氧对大鼠心脏功能和结构影响的定量研究

目的定量研究在缺氧情况下,心脏结构和功能改变及其规律。方法W istar大鼠40只,雌雄各半,随机分为对照组和单纯缺氧组,置于本课题组设计并研制的常压低氧舱（氧浓度为10%）,采用生化、常规病理、超微病理、分子病理和定量病理等多种技术方法,对缺氧后心脏功能、结构和心肌细胞凋亡进行观察。结果缺氧后大鼠心肌酶谱（LDH、AST和CK）均明显高于正常值,且随实验时间延长而增加; PO2在缺氧1-7 d内呈持续性进行性下降,PCO2于缺氧1 d时显著升高,而于3-7 d内则呈持续性下降。pH值于缺氧1 d时显著低于正常对照组、而于3-7 d内则迅速恢复到对照组的水平。HCT（%）于缺氧1-7 d内呈持续性进行性升高; 缺氧后大鼠心肌细胞肿胀、变性、凋亡、坏死; 心肌纤维排列紊乱; 间质细胞肿胀、退变; 心肌细胞凋亡指数增加。结论缺氧引起大鼠心脏功能和结构明显损伤,且随缺氧时间延长呈进行性加重趋势; 缺氧后心肌细胞凋亡指数增加,可作为缺氧时心脏损伤的一个重要指标。

Quantitative studies on the effects of hypoxic environment on the structure and function of rat hearts

Objective To investigate quantitatively the structural and functional changes of the heart under hypoxic condition . Methods Forty Wistar rats were randomly divided into control group and hypoxic group. The rats of hypoxic group were put into hypoxic cabin at natural pressure. The structure and function of the heart including histology and apoptosis of cardiomyocytes were detected using biochemistry, histology, transmission electron microscopy, and quantitative pathology. Results The values of LDH, AST and CK of the hypoxic rats were higher than that of the control group and the increase became more prominent as time went by. POE of hypoxic rats decreased continuously after one to seven days in hypoxic environment. PCO2 of hypoxic rats was higher than that of control rats after one day in the hypoxic cabin, while after three to seven days in hypoxic cabin the PCO2 of the hypoxic rats reduced continuously, pH of the hypoxic group was lower than that of the control group after one day in the hypoxic cabin but then returned to normal level after three to seven days in the hypoxic cabin. HCT （%） reduced continuously after one to seven days in the hypoxic cabin. Some cardiomyocytes were swelled, degenerated, apoptotic or necrotic. The arrangement of myocardial fibers was disorganized. The interstitial cells were swelled and degenerated while the apoptosis index of cardiomyocytes was increased. Conclusions The structure and function of rat hearts are injured under hypoxic condition and the injury becomes more serious as the hypoxic time is prolonged. The apoptosis index of hypoxic cardiomyocytes increases and that may be an important parameter of the myocardial injury caused by hypoxia.