早期应用 AICAR 对缺氧缺血性脑病新生大鼠的保护作用

摘要

Objective To investigate the neuroprotective effects and mechanisms of 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/ IMP cyclohydrolase(AICAR) supplement (AMPK activator) in different stages of neonatal rats sufferring from hypoxia-ischemia encephalopathy ( HIE). Methods Neonatal rat hypoxia-ischemia brain injury model was employed in this study. A total of 160 neonatal rats were distributed into five groups: sham, model control,AICAR30 min, AICAR24 h and AICAR72 h. The neuroprotective effects of AICAR supplement (30 min, 24 h, 72 h post operation) were compared by cresyl violet staining; Expressions of P-AMPK,AMPK in the brain tissue were measured by Western blotting.Foot-faults method was used to evaluate the long-term prognosis of the rats. Results Compared with the sham group, the survival of rats brain in model control group was significantly decreased [(100.0± 0.1)% and (45.3± 6.3)%, P< 0.05]. AICAR had neuroprotective effects when treated at 30 min and 24 h post operation,while the protective effects disappeared when treated later (72 h post operation) (P>0.05). Compared with the sham group, the expression of P-AMPK significantly increased about three times, while ATP level decreased close to the same. Conclusion Early AICAR treatment can protect hypoxia-ischemia brain injury by increasing AMPK-ATP level.%目的：在新生大鼠缺氧缺血性脑病(HIE)发病的不同时期应用单磷酸腺苷激活的蛋白激酶(AMPK)激活剂5-氨基咪唑-甲酰胺核苷酸转甲酰酶(AICAR)，观察其保护作用，探讨其作用机制。方法新生大鼠160只，分为假手术组、模型对照组、AICAR30 min 组、AICAR24 h 组和 AICAR72 h 组，各32只。采用 Cresyl violet 染色法比较手术后不同时间点(30 min，24 h，72 h)给予 AICAR(500 mg•kg－1)对脑组织保护作用的差异；采用 Foot-faults 法评估大鼠远期预后；蛋白质印迹法检测脑组织中 P-AMPK 及三磷酸腺苷(ATP)的表达变化。结果假手术组与模型对照组大脑存活面积比例分别为(100.0±0.1)％和(45.3±6.3)％(P<0.05)；手术后30 min、24 h 给予 AICAR 治疗均有不同程度的保护作用，且手术后30 min 治疗效果优于24 h(P<0.05)，手术后72 h 给予 AICAR 没有发现明显的保护作用(P>0.05)。早期给予AICAR 治疗后可增加 P-AMPK 活性至假手术组约3倍，ATP 含量可升至接近假手术组水平(P<0.05)。结论 HIE 发病早期补充 AICAR 可调控 AMPK 信号通路，增加 ATP 含量，保护受损的神经元。