重复高压氧预处理对大鼠脊髓缺血再灌注损伤时糖调节蛋白78表达的影响

Effect of Repeated Hyperbaric Oxygen Preconditioning on GRP78 Expression in Spinal Cord Following Spinal Ischemia-reperfusion in Rattus

目的探讨重复高压氧预处理对大鼠脊髓缺血再灌注损伤保护中糖调节蛋白78(GRP78)表达的影响。方法雄性SD大鼠36只,体重250～300g,采用随机数字表法,将其随机分为3组(n=12)假手术组(S组)、脊髓缺血再灌注组(I/R组)和重复高压氧预处理(HOP组)。HOP组采用高压氧预处理[1000ml/L O2,2.5 atmosphere absolute(ATA),1h/d,5天],最后一次处理后24h,I/R组和HOP组采用Zivin法制备脊髓缺血再灌注模型(缺血15min,再灌注1h),24、48、72h后分别评价后肢运动功能,然后处死大鼠,取L5～7节段脊髓组织,测定GRP78的mRNA及其蛋白表达水平,光镜下观察病理学结果。结果与S组比较,I/R组和HOP组后肢运动功能和脊髓前角正常运动神经元计数降低,脊髓组织GRP78 mRNA及蛋白表达水平上调(P<0.05);与I/R组比较,HOP组后肢运动功能和脊髓前角正常运动神经元计数升高,脊髓组织GRP78 mRNA及蛋白表达水平上调(P<0.05)。HOP组脊髓组织病理学损伤程度轻于I/R组。结论重复高压氧预处理可上调大鼠脊髓缺血再灌注时GRP78表达,从而减轻大鼠脊髓缺血再灌注损伤。

Objective To investigate the protective effect of repeated hyperbaric oxygen preconditioning on GRP78 expression in spi- nal cord following spinal ischemia - reperfusion in rats. Methods A total of 36 male SD rats were randomly divided into 3 groups （ n = 12 each） ： group sham operation （S group） ; group spinal cord ischemia- reperfusion （I/R group） and group hyperbaric oxygen pretreatment （HPO group）. The animals in HPO group received HBO treatment （1000mL/L 02, 2. 5 ATA, 1 h/d, 5days） , 24h after the last treat- ment. In I/R and HPO group, Zivin method was adopted to induce Spinal cord ischemia - reperfusion model（ 15 minutes ischemia then 60 minutes reperfusion）. Hind limb motor function in rats was evaluated at 24,48 and 72hs resceptively using BBB score method. Then rats were killed, Spinal cords （L5 -L7） were removed immediately for histopathologic examination. Fluorescence quantitative PCR and WB method were used to detect the expression of GRP78. Results Compared with S group, BBB score of hind limb motor function and nor- mal anterior horn neurons counts in I/R and HPO groups were lower, GRP78 mRNA and protein expression levels were higher. Compared with I/R group, BBB score of hind limb motor function and normal anterior horn neurons counts in HPO group were higher, GRP78 mR- NA and protein expression levels were higher. The degree of spinal cord pathology injury in HOP group was less than in I/R group. Con- clusion Protective effect of repeated hyperbaric oxygen pretreatment on spinal cord ischemia - reperfusion injury may be through in- creased the expression of GRP78.