高压氧对脑损伤后脑组织Bcl-2及Bax表达的影响(英文)

Effect of hyperbaric oxygenation on the expression of Bcl-2 and Bax after traumatic brain injury

背景:国内外大量临床及实验报道,高压氧对严重颅脑损伤具有治疗意义,但目前对高压氧通过何种机制产生治疗作用尚未达成共识,可能与细胞凋亡而非细胞坏死有关。目的:探讨高压氧对创伤性脑损伤的治疗作用与脑组织Bcl-2及Bax蛋白的表达之间的关系。设计:完全随机设计,对照实验研究。地点与材料:本实验在上海第二医科大学神经创伤与脑血管病研究室的实验室内进行。实验动物为购自上海医科大学实验动物中心的SD大鼠。SD雄性大鼠56只,随机分为假手术组、外伤组和伤后高压氧治疗组,后两组又分别为8h,24h和48h组,共7组。干预:以50g×15cm冲击力自行制作自由落体脑挫裂伤动物模型(SD大鼠),设立高压氧治疗组和对照组,分别使用WesternBlot和免疫组化方法检测Bcl-2及Bax蛋白在脑组织的表达情况。主要观察指标:WesternBlot检测脑外伤后及高压氧治疗前后Bcl-2及Bax蛋白的脑组织表达。免疫组化检测脑外伤和高压氧治疗前后阳性细胞计数。结果:创伤性脑损伤后脑挫裂伤灶和海马结构Bcl-2及Bax蛋白的表达均明显增强,高压氧治疗组Bcl-2的表达明显强于对照组(P<0.05),而Bax虽在各组均有表达,但在各组间无显著性差异(包括假手术组)。结论:研究表明高压氧治疗对创伤性脑损伤后脑组织Bcl-2蛋白表达有显著影响。

BACKGROUND:A number of clinical and experimental studies have demonstrated the effectiveness of hyperbaric oxygenation(HBO) on severely injured cerebral tissu e.However,the underlying mechanisms remain unclear.One of the hypotheses is that it is associated with apoptosis but not cell death. OBJECTIVE:To investigate the effect of HBO on injured cerebral tissue and on t he expression of Bcl-2 and Bax proteins. DESIGN:Completely randomized controlled experimental study. SETTING and MATERIALS:The experiment was carried out in the Laboratory of the Institute of brain Injury and Cerebrovascular Diseases,Shanghai Secondary Medica l University.Experimental SD rats were purchased from the Animal Center of Shang hai Medical University.Fifty-six rats were randomly divided into sham operation group,injury group and post-injury HBO group.The latter two groups were furthe r divided into 6 subgroups according to the experiment time duration(8, 24 and 4 8 hours). INTERVENTION:Controlled cortical impact injury(CCI) was induced with a force o f 50 g×15 cm.Expression of Bcl-2 and Bax proteins in the control and HBO group s were tested by Western Blot and immunohistochemistry. MAIN OUTCOME MEASURES:The expression of Bcl-2 and Bax proteins, and the numbe r of positive cells after brain injury,before and after HBO. RESULTS:There were increased expression of Bcl-2 and Bax in the injury area.E xpression of Bcl-2 was significantly higher in the HBO group than that in the c ontrol group(P< 0.05).There was no significant difference in the expression of B ax among different groups. CONCLUSION:It has been demonstrated that the HBO has significant effect on the expression of Bcl-2 and results in the changed ratio of Bcl-2/Bax which has c lose relationship with apoptosis of cerebral neurons.It suggests that inhibition of apoptosis plays an important role in the effective treatment of traumatic br ain injury by HBO.