缺血-再灌注损伤大鼠心肌中解偶联蛋白2的表达及可能意义

A pilot study: function of uncoupling protein 2 in cardiac muscle after ischemia and reperfusion injury in rats

关键词:  心肌  缺血再灌注  解偶联蛋白2  肌酸磷酸激酶  丙二醛

Key words:  cardiac muscle  ischemia and referfusion  uncoupling protein 2  creatine phosphokinase  malondialdehyde

摘要:

［目的］研究解偶联蛋白2（UCP₂）在大鼠心肌缺血-再灌注（I/R）损伤中的表达及作用。［方法］将SD大鼠随机分为假手术组、缺血组和缺血再灌注组。采用标准II导联监测大鼠心电图变化。测定大鼠血清肌酸磷酸激酶（CPK）、心肌组织丙二醛（MDA）含量变化。HE染色方法观察心肌组织形态学变化，免疫组织化学检测心肌组织UCP₂的表达。［结果］与假手术组相比，缺血组大鼠心电图ST段明显抬高，再灌组ST段亦明显抬高，并出现室性心动过速和（或）室颤。HE染色可见缺血组大鼠部分心肌纤维断裂，部分细胞核有浓缩或溶解，间质轻度充血及炎性细胞浸润；再灌组心肌纤维横纹消失，可见大量炎性细胞浸润、充血。假手术组大鼠血清CPK值为（1.00±0.44）kU/L（n=8），缺血和缺血再灌注后CPK值分别为（5.02±1.08） kU/L和（8.23±1.15） kU/L，较假手术组均显著升高（P<0.05，P<0.01，n=8）。假手术组心肌组织MDA含量为（1.03±0.14）nmol/mg(n=8)，缺血和缺血再灌注后MDA含量分别为 （1.37±0.21） nmol/mg和 （1.67±0.08） nmol/mg，较假手术组亦显著升高（P<0.05，P<0.01，n=8）。缺血组和再灌注组心肌组织UCP₂表达较假手术组均增加。［结论］大鼠心肌UCP₂表达与缺血再灌注损伤相关，并可能通过降低活性氧的产生而起保护作用。

Abstract:

［Objective］Uncoupling protein 2（UCP₂）acts as a protective agent by decreasing production of reactive oxygen species. However, the function of UCP₂ in cardiac muscle after ischemia and reperfusion (I/R) injury remains unclear. This study is to investigate the effects of UCP₂ in the cardiac muscle after I/R injury in rats.［Methods］SD rats were divided randomly into sham operation, ischemia, and I/R groups. To make cardiac muscle I/R model by detecting ECG by lead II, the morphological changes was assessed by HE staining, and creatine phosphokinase (CPK) in the serum and malondialdehyde (MDA) contents in the cardiac tissue were measured. The expression of UCP₂ was detected by immunohistochemistry.［Results］Compared with sham group, the elevated ST segment in the ECG was observed in ischemia and I/R groups, even tachycardia and/or ventricular quiver in I/R group. The unclear cell bordering, weakly stained cytoplasm, part concentrated or dissolved nucleolus, mild congestion and infiltered inflammation cells could be observed in cardiac muscle with ischemia treatment, and more infiltered inflammation cells and disappeared transverse strips in myocardial fibers were observed in cardiac muscle with I/R treatment by HE staining. CPK values were significantly increased in ischemia (5.02±1.08) kU/L, (P<0.05, n=8) and I/R groups (8.23±1.15) kU/L, (P<0.01，n=8) compared with sham group (1.00±0.44 kU/L). MDA contents were also markedly increased in ischemia (1.37±0.21) nmol/mg, (P<0.05, n=8) and I/R groups (1.67±0.08) nmol/mg, (P<0.01，n=8) compared with sham group (1.03±0.14) nmol/mg, (n=8). Moreover, UCP₂ expression was increased significantly in the ischemia and I/R groups.［Conclusions］UCP₂ may play a role in the cardiac muscle against ischemia-reperfusion injury by decreasing production of reactive oxygen species.