新生大鼠缺氧缺血后海马caspase-3 mRNA的表达及硫酸镁的神经保护机制研究

目的　探讨caspase 3mRNA在新生大鼠缺氧缺血后海马中的表达 ,研究硫酸镁对脑损伤可能的保护机制。方法　制作新生大鼠缺氧缺血模型 ,按治疗方式不同随机分为 :①正常对照组(n =4) ;②假手术组 (n =4) ;③缺氧缺血组 (n =4) ;④生理盐水对照组 (n =4) ;⑤硫酸镁预防组(n =4) ;⑥硫酸镁治疗组 (n =4)。预防组和治疗组分别在缺氧缺血前或后 0 5h腹腔注射 5 %硫酸镁5 0 0mg/kg。半定量RT PCR法测定缺氧缺血后 2 4h海马组织caspase 3mRNA的表达 ,比较两个硫酸镁干预组与对照组的差异。结果　正常对照组新生大鼠海马组织中caspase 3mRNA相对表达量为0 97± 0 46,缺氧缺血组海马组织中caspase 3mRNA表达量增高至 1 88± 0 3 6,与正常组相比差异有显著意义 (P <0 0 5 ) ;硫酸镁预防组与治疗组表达量分别是 1 5 4± 0 49和 1 65± 0 48,与缺氧缺血组相比差异有显著意义 (P <0 0 5 ) ,硫酸镁干预抑制了缺氧缺血后海马组织中caspase 3mRNA的表达。结论　新生大鼠缺氧缺血后 2 4hcaspase 3mRNA在海马中的表达明显增高 ,硫酸镁对缺氧缺血脑组织的保护作用可能与抑制海马caspase 3mRNA表达有关

Expression of caspase-3 mRNA in the hippocampus of seven-day-old hypoxic-ischemic rats and the mechanism of neural protection with magnesium sulfate

OBJECTIVE: There was consanguineous relationship between caspase-3 and early damage after hypoxia and ischemia. Caspase-3 plays a key role in the process of apoptosis in neuron. Magnesium sulfate could protect neuron from injuries, but the mechanism was not clear. The study was to investigate the expression of caspase-3 mRNA in the hippocampus of seven-day-old hypoxic-ischemic rats and the possible mechanism of neural protection with magnesium sulfate. METHODS: The model of seven-day-old hypoxia-ischemia rats was established. The rats were divided randomly into 6 groups as follows: (1) normal control (n = 4); (2) sham surgery control (n = 4); (3) hypoxia-ischemia (n = 4); (4) sodium chloride injection with hypoxia-ischemia (n = 4); (5) magnesium sulfate pre-injection with hypoxia-ischemia (n = 4); (6)magnesium sulfate post-injection with hypoxia-ischemia (n = 4). The therapy groups received a bolus injection of 500 mg/kg magnesium sulfate intraperitoneally 0.5 hour before or after hypoxia-ischemia. Semi-quantitative RT-PCR was used to measure caspase-3 mRNA expression in the hippocampus 24 hours after hypoxia-ischemia. RESULTS: The expression of caspase-3 mRNA was significantly increased in the hippocampus of the hypoxia-ischemia pups (1.88 +/- 0.36 vs 0.97 +/- 0.46, P < 0.05). The expression of caspase-3 mRNA in rats with magnesium sulfate pre-injection and post-injection decreased significantly (1.54 +/- 0.49, 1.65 +/- 0.48 vs 1.88 +/- 0.36, P < 0.05). CONCLUSION: Caspase-3 was activated in the hippocampus of the seven-day-old rats 24 hours after hypoxia-ischemia. The suppression of the expression of caspase-3 mRNA in the hippocampus was probably related to the protective effect of magnesium sulfate on the brain injury of hypoxia-ischemia.