缺血预适应对肢体缺血再灌注后肺组织细胞凋亡的影响

Effects of Ischemic Preconditioning on Apoptosis of Lung following Limbs Ischemia Reperfusion in Rats

目的观察并探讨缺血预适应对大鼠肢体缺血再灌注后肺组织细胞凋亡的影响。方法将雄性Wistar大鼠随机分为对照组(C)、肢体缺血再灌注组(LIR)、缺血预适应组(IPC),每组8只。各组大鼠均于肢体缺血4h再灌注4h后处死,分别测定其动脉血氧分压(PaO2)和二氧化碳分压(PaCO2)、肺湿干比(W/D)、肺系数(LI),检测肺组织细胞凋亡情况,检测Bcl-2、Bax、Caspase-3蛋白表达情况,结合计算机自动图像分析系统对其结果进行定量分析,在光学显微镜下观察肺组织的形态学改变。结果 LIR组大鼠的PaO2明显下降,光镜下可见肺间质充血,肺泡腔内有渗出液,支气管上皮细胞脱落坏死。TUNEL法显示,肺泡上皮细胞和肺血管内皮细胞呈凋亡改变。而与LIR组比较,IPC组PaO2明显增加,凋亡细胞数也明显减少,肺组织损伤性改变明显减轻。免疫组化结果显示,LIR组肺组织Caspase-3、Bax抗原表达明显上调,Bcl-2表达亦上调,但不如前几项明显。IPC组肺组织Caspase-3、Bax的表达情况与LIR组相比明显减轻,Bcl-2表达明显增强,Bcl-2/Bax比值增大。各组大鼠PaCO2的变化无显著性。结论 IPC可以减少LIR后肺组织细胞凋亡,可能是通过影响细胞凋亡相关蛋白的表达而实现的。

Objective To study the effects of ischemic preconditioning on apoptosis of lung following ischemia/reperfusion（I/R） in the hind limbs of rats. Methods Wistar rats were randomly divided into three groups（n = 8）：control group, limbs ischemia/reperfusion（LI/R） group, ischemia preconditioning （IPC） group. At the end of the experiment, blood/gas analysis and lung index and W/D of lung were measured. Apoptosis was detected by TUNEL. The immunohistochemieal method was used to detect the expression of Bcl-2, Bax, Caspase-3 in lung tissue, and the results were analyzed quantitatively by relative computer analytical system. The morphologie changes were observed with microscope. Results After the rats hind limbs suffered ischemia/reperfusion, the level of PaO2 decreased and the values of W/D, LI increased significantly in the LI/R group; pulmonary pathology revealed that after LI/R there were congestion in pulmonary microvessels and leucocyte infiltration dominated by neutrophils. Bronchial epithelial cells（BEC） became deteriorated and necrosed. TUNEL results showed the appearance of apoptosis in alveolar epithelial cells and pulmonary vascular endothelial cells. Compared with LI/R group, the value of PaO2 upregulated in the IPC group, apoptotic cells decreased obviously, the results of the light microscope clued that the lung injury were lightened. Histoehemieally, in LI/R group, the activity of Caspase 3 , Bax in the bronchi duct and alveolar and vascular endothelial cells and inflammatory cells were signifi -cantly stronger than that in normal ones, the activity of Bcl-2 in those cells were stronger than that in normal ones but not significantly as those former few factors. Compared with LI/R rats, the expression of Caspase-3,Bax were not obvious in the IPC group, the expression of Bcl-2 was obvious in those group, the ratio of Bcl-2/Bax was higher significantly. Conclusion The IPC can attenuate apoptosis of lung following IR in the hind limbs of rats, which may correlated with reducing the occurrence of apoptosis by regulating the express of protein which is correlated with cell apoptosis.