高压氧大鼠脑缺血再灌注损伤细胞凋亡的作用研究

Apoptosis of neural cells after global cerebral ischemia-reperfusion injury and the therapeutic effects of hyperbaric oxygenation in rats

目的 :证实全脑缺血再灌注损伤 (CIRI)中凋亡的存在及高压氧 (HBO)的治疗作用。方法 :72只 SD大鼠随机分为假手术组、常压空气组、高压空气组和 HBO组。用四血管法制备 CIRI模型 ,缺血 15分钟后再灌注 2小时 ,HBO组每日置于 2 .5 ATA (0 .2 5 MPa)纯氧 (体积分数 95 % )环境中 70分钟 ;高压空气组则置于2 .5 ATA和 2 1%的氧浓度环境。再灌注 72小时后 ,所有大鼠断头取脑。用流式细胞仪 (PI染色 )、原位末端标记法 (TUNEL )检测细胞凋亡情况。结果 :在常压空气组和高压空气组中 ,海马 CA1区 TU NEL染色阳性细胞计数分别为 (10 3± 15 )个和 (96± 12 )个 ,明显多于假手术组和 HBO组的 (5± 3)个和 (17± 6 )个 (P均 <0 .0 1)。在常压空气组和高压空气组 ,流式细胞术显示明显的亚二倍体峰 ,凋亡细胞百分比分别为 (1.0 6± 0 .4 8) %和(0 .87± 0 .5 0 ) % ,明显高于假手术组和 HBO组的 (0 .34± 0 .0 8) %和 (0 .5 7± 0 .37) % (P均 <0 .0 5 )。结论 :在脑缺血再灌注后凋亡机制在海马 CA1区可能有重要作用 ,这可能为防止 CIRI提供一条新的途径。HBO能减少海马 CA1区的细胞凋亡 ,提示 HBO防止 CIRI的机制可能与抑制细胞凋亡有关。

Objective:To prove the existence of apoptosis of neural cells and the therapeutic effect of hyperbaric oxygenation (HBO) after global cerebral ischemiareperfusion injury (CIRI).Methods:Seventytwo SD rats were randomly divided into 4 groups:sham operation group,atmospheric pressure group,hyperbaric air group and HBO group.CIRI was induced by fourvessel occlusion (4VO) for 15 minutes followed by reperfusion for 2 hours.In HBO group rats were subjected to 2 5 ATA (0 25 MPa),95% O 2 concentration for 70 min/d. In hyperbaric air group the rats were treated with 2 5 ATA (0 25 MPa),21% O 2 concentration for 70 min/d. All rats were killed 72 hours after reperfusion.The brain cells were examined with flow cytometry (FCM) and terminal deoxynucleotidyltransferasemediated dUTP nick endlabeling (TUNEL).Results:In atmospheric pressure group and hyperbaric air group,the number of TUNEL stained cells in hippocampal CA1( 103±15 and 96±12 ) was markedly higher than those in sham operation group and HBO group(5±3 and 17±6, all P <0 01).FCM showed obvious subG1 peak.Apoptotic percentages were (1 06±0 48)% and (0 87±0 50)%,respectively,in atmospheric pressure group and hyperbaric air group.These levels were obviously higher than those in sham operation group and HBO group〔(0 34±0 08)%,(0 57±0 37)%,all P <0 05).Conclusions:Apoptosis may take place in the hippocampus CA1 after cerebral ischemiareperfusion.It may provide novel therapeutic approaches for prevention of CIRI.HBO reduces apoptosis in the hippocampus CA1.The preventive mechanism of HBO against CIRI is likely correlated with reduction of apoptosis.