Tempol预处理对大鼠心肺复苏后脑内缺氧诱导因子-1α及血管内皮生长因子变化的影响

Effects of tempol preconditioning on the expression of hypoxia inducible factor-1α and vascular endothelial growth factor after brain injure induced by cardiac arrest in rats

目的探讨Tempol预处理对心肺复苏后大鼠神经功能及脑组织中缺氧诱导因子-1α(HIF-1α)和血管内皮生长因子(VEGF)表达的影响。方法雄性SD大鼠72只,随机分为空白对照组(C组)、Tempol预处理组(T组)和常规复苏组(S组),每组24只。S组和T组采用窒息后心跳骤停法建立大鼠全脑缺氧缺血脑损伤模型,C组大鼠仅行气管插管不夹闭窒息。D组于气管夹闭前5 min腹腔注射Tempol 100 mg/kg,S组和C组分别给予等容量生理盐水,于自主循环恢复后6、12、24和48 h随机抽取6只大鼠进行神经功能评分后处死取脑内海马组织,HE染色观察细胞组织形态改变,免疫组化检测HIF-1α及VEGF的表达。结果与C组比较,S组和T组在12、24和48 h时神经功能评分升高(P<0.05)。与S组比较,T组在12、24和48 h时神经功能评分降低(P<0.05);HE染色可见S组大鼠海马组织24 h和48 h时神经细胞排列散乱,水肿疏松、空泡化,胞核浓缩、深染,细胞弥漫性胀大,胞浆淡染,胞核已有增大,神经细胞和血管周间隙明显增加。与S组比较,T组在24 h和48 h时损伤程度轻、范围小,水肿改变得到改善;与S组比较,T组海马内HIF-1α在12 h和24 h表达明显增强(P<0.05),VEGF在6、12和24 h表达明显增强(P<0.05)。结论 Tempol预处理缺血缺氧损伤的脑组织神经功能的恢复具有保护作用,其保护机制可能与激活HIF-1α及VEGF的表达有关。

Objective To investigate the effects of Tempol preconditioning onthe expression of hypoxia inducible factor-1α （HIF-1α） and vascular endothelial growth factor （VEGF） after brain injure induced by cardiac arrest in rats. Methods Seventy-two adult male SD rats were randomly divided into 3 groups （n=24）： control group （Croup C）, cardiopulmonary-cerebral resuscitation group （Group S） and Tempol preconditioning group （Group T）. Cerebral hypoxia-reperfusion injury model was constructed by mechanical asphyxia. Intraperitoneal injection of Tempol （100 mg/kg） was performed in Group T five min before CPR. The neurological deficit score was assessed at the 6th, 12th, 24th and 48th hour, after which 6 rats were sacrificed in each group to collect the brain tissues for HE microscopic examination and HIF-1α and VEGF expression assessment.Results Compared with Group C, the neurological deficit score was significantly increased in Group T at the 12th, 24th and 48th hour （P〈0.05）. Compared with Group S, the neurological deficit score was significantly reduced in Group D at the 12th, 24th, 24th and 48th hour （P〈0.05）. There was no marked pathological change in Group C, while marked reduction in neurons in hippocampus in Group S were was observed with sparse arranged cells, deformed shape, karyopyknosis, light stained cytoplasm, uneven dye color marks and fuzzy neucleo; which was partly reversed in Group T at the 24th and 48th hour. According to immunohistochemistry, compared with Group S, expression of HIF-1α was up-regulated in Group T at the 12th and 24th hour; so was the expression of VEGF at the 6th, 12th and 48th hour.Conclusion Tempol preconditioning can attenuate cerebral hypoxia-reperfusion injury in rats, which is correlated to the up-regulation of HIF-1α and VEGF in hippocampus.