目的观察高压氧( HBO)作用下脑缺血再灌注海马 CA1区神经元 Bcl- 2和 Bax蛋白表达的变化情况,进一步研讨高压氧治疗脑缺血再灌注损伤、减轻神经元凋亡从而发挥保护作用的机制.方法沙土鼠 20只,采用随机数字法将实验动物分为正常对照组、缺血组、 0.15 MPa HBO治疗组、 0.25 MPa HBO治疗组, 0.25 MPa压力空气 ( hyperbaric air, HBA) 对照组,每组 4只动物.采用 "双侧颈总动脉阻断法"前脑缺血模型,缺血 20 min后再灌注 3 d,并用 0.15 MPa和 0.25 MPa压力的高压氧治疗 ( 60 min/d,连续 3d )后,应用免疫组化 LSAB方法,观察高压氧对海马 CA1区神经元凋亡相关基因 Bcl- 2和 Bax的蛋白表达的影响.结果沙土鼠脑缺血再灌注 3 d组海马 CA1区大量神经元表达 Bax蛋白,并且神经元发生凋亡,未见神经元表达 Bcl- 2蛋白;高压氧治疗组则大量神经元表达 Bcl- 2蛋白,并且 0.25 MPa高压氧治疗组比 0.15 MPa高压氧治疗组变化更显著,而各组表达 Bax蛋白的神经元数目无明显变化,但高压氧治疗组 Bax蛋白阳性的神经元形态正常.结论 HBO暴露可诱导大量神经元表达 Bcl- 2蛋白,对 Bax蛋白表达则无明显作用,使 Bcl- 2和 Bax蛋白表达的比值增高,从而起到保护神经元的作用,这可视为 HBO治疗脑缺血性损伤减少神经元凋亡的机制之一.%Aim To observe the expressions of Bcl- 2 and Bax proteins at CA1 area of hippocampus in hyperbaric oxygen(HBO) and explore the mechanisms of hyperbaric oxygen treatment ( HBOT ) reducing neuronal apoptosis following forebrain ischemia reperfusion.Methods 20 gerbils were randomly divided by random number table into normal control group,ischemia group,0.15 MPa HBO, 0.25 MPa HBO and 0.25 MPa hypervaric air (HBA) control group with 4 gerbils in each group.Forebrain ischemia model was established by bilateral common carotid arteries blocking.Animals were reperfused for 3 days after 20 minutes of ischemia and treated by 0.15 MPa and 0.25 MPa of hyperbaric oxygen(60 min/d for 3 days).Thereafter,expressions of Bcl- 2 and Bax protein were observed by immunohistochemical labelled streptavidin biotin (LSAB) method.Results The expression of protein Bcl- 2 in hippocampus CA1 was significantly increased in HBOT groups (P< 0.01), and changes in 0.25 MPa groups were greater than those in 0.15 MPa groups (P< 0.01).The expression of protein Bax in hippocampus CA1 was not changed significantly in HBOT groups.Conclusion HBO can induce the expression of Bcl- 2,which is the mechanism of neuronal protecting effect of HBOT.
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