缺血预处理对人在体肺组织细胞凋亡及调控基因蛋白bcl—2表达的影响

目的：通过对需阻断一侧肺动脉主干行肺叶切除的患者进行实验观察，以了解人肺组织缺血再灌注损伤是否促进肺组织细胞凋亡，以及缺血预处理对人在体肺组织细胞凋亡和对其凋亡基因bcl-2宾影响。方法：选择16例需阻断一侧肺动脉才能行肺叶切除的病例随机分为对照组与缺血预处理组，每组8例。预处理采用阻断5min，开放5min两周期的缺血预处理方式，对照组则无参处理过程，余同预处理组。分别于缺血前，缺血30min，再灌30min和再灌60min取余肺组织少许，采用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法（TUNEL）检测细胞凋亡，用免疫组织化学法检测bcl-2蛋白表达水平。结果：TNUEL检测显示对照组中再灌30min后与再灌60min后较术前细胞凋亡指数显著增加（P＜0.05），随着再灌时间延长，凋亡细胞指数也呈显著增加趋势（P＜0.05）。免疫组化显示，缺血预处理组bcl-2蛋白表达较对照组显著增加（P＜0.05），对照组中各时间点其表达水平并无差异（P＞0.05）。结论：①缺血再灌注能促进人在肺组织细胞凋亡。②缺血预处理可能通过上调bcl-2蛋白的表达来抑制人在体肺组织细胞凋亡。

Effect of ischemic preconditioning on human lung cell apoptosis in vivo and the expression of regulating gene bcl-2]

OBJECTIVE: To investigate whether ischemic reperfusion injury induces lung cell apoptosis and the effect of ischemic preconditioning on lung cell apoptosis by altering the expression of bcl-2 protein. METHODS: Sixteen patients, who needed to occlude the main pulmonary artery to undergo pulmonectomy, were randomly put to two groups: the control group (Group C) and the ischemic preconditioning group (Group I). Ischemic preconditioning was achieved by two 5-minute cycles of ischemic, and each was followed by a 5-minute reperfusion. The lung tissue was sampled at the time of preoccluding, 30 minutes after the ischemic, and 30 and 60 minutes after the reperfusion. Apoptotic cells were stained by the terminal deoxynucleotidyl transferase-mediated dUTP nickend labeling (TUNEL) technique. Immunohistochemistry was used to detect the expression of bcl-2 protein. RESULTS: The apoptosis index (AI) of lung cells increased significantly 30 and 60 minutes after the reperfusion, and also significantly increased as the reperfusion period prolonged. Apoptosis was significantly reduced in Group I 30 and 60 minutes after the reperfusion compared with that of Group C at the same time points (P < 0.05). Immunohistochemistry analysis showed that the expression of bcl-2 protein significantly increased in Group I compared with that of Group C(P < 0.05), while there was no significant difference at each time point in Group C(P > 0.05). CONCLUSION: 1. Ischemic reperfusion injury may induce human lung cell apoptosis. 2. Ischemic preconditioning may reduce the apoptosis of human lung cells in vivo by upregulating bcl-2 protein expression.