丙二醛和腺苷A_1受体在幼年和成年大鼠皮层注射FeCl_3所致痫性发作中的表达

Expression of MDA and A1R in young and adult rats with epileptic seizure after intracortical injection of ferric chloride

目的探讨丙二醛(malondialdehyde,MDA)和腺苷A1受体(adenosine A1 receptor,A1R)的表达差异与幼年和成年大鼠皮层注射FeCl3所致痫性发作的相关性及其在大鼠痫性发作中的可能机制。方法 12只成年大鼠分为对照组和模型组,分别皮层注射生理盐水和FeCl3;18只幼鼠分为3组:对照组和模型组处理同对应成年大鼠;干预组大鼠皮层注射FeCl3前30 min行腹腔注射A1R拮抗剂(DPCPX)处理。大鼠被严密观察6 h后处死,用硫代巴比妥酸(TBA)法检测脑脊液中MDA含量,RT-PCR、Western blot检测注射皮层A1R表达。结果模型组、干预组大鼠出现典型的痫性发作;幼鼠模型组较成年鼠模型组癫痫发作次数明显增多[(12.70±7.63)次vs(3.20±2.37)次,P<0.01];干预组[(13.10±7.71)次]与幼鼠模型组之间典型癫痫发作次数无统计学差异(P>0.05);幼鼠模型组癫痫发作程度较重,持续时间较长,与成年鼠模型组比较,差异显著[(10.17±6.73)min vs(2.43±1.87)min,P<0.01];干预组大鼠癫痫发作程度最重,持续时间最长(14.25±5.82)min,与幼鼠模型组比较,差异显著(P<0.05)。与生理盐水对照组比较,模型组注射区域脑皮层A1R mRNA表达下降(P<0.05),且幼鼠较成年鼠表达下降趋势更为明显(P<0.05);干预组注射区域脑皮层A1R mRNA表达与幼鼠模型组比较,下降更为显著(P<0.05)。A1R蛋白表达趋势与RT-PCR检测结果一致。与生理盐水对照组比较,模型组大鼠脑脊液中MDA表达升高(P<0.05),且幼鼠较成年鼠表达升高趋势更为明显(P<0.05);干预组幼鼠脑脊液中MDA表达与幼鼠模型组比较,升高最为显著(P<0.05)。结论 MDA升高和A1R下降程度不同,可能是幼年和成年大鼠不同痫性发作的原因之一。

Objective To study the correlation between the expression of malondialdehyde（MDA） and adenosine A1 receptor（A1R） and the epileptic seizures in young and adult rats after intracortical injection of ferric chloride,and to explore the roles of MDA and A1R in epileptic seizure of rats.Methods Eighteen young rats were randomized into a control group,a model group,and an intervention group,while twelve adult rats were randomized into a control group and a model group.In the control groups,saline was given to the rats by intracortical injection.In the model groups,ferric chloride was given to the rats by intracortical injection.In the intervention group,the rats were subjected to intraperitoneal injection of A1R antagonist 1,3-dipropyl-8-cyclopentyl xanthine（DPCPX） 30 min before intracortical injection of ferric chloride.All the rats were sacrificed after 6-hour careful observation.Thiobarbituric acid（TBA） method was used to measure the MDA content in cerebrospinal fluid（CSF）.RT-PCR and Western blot were used to measure the expression of A1R in the cortex.Results Epileptic seizure was found in the model groups and intervention group.The model group of young rats had significantly more epileptic seizures than the model group of adult rats（12.70±7.63 times vs 3.20±2.37 times,P0.01）,showing no significant difference as compared with the intervention group（12.70±7.63 times vs 13.10±7.71 times,P0.05）.The model group of young rats had significantly higher severity and longer duration of epileptic seizure than the model group of adult rats（10.17±6.73 min vs 2.43±1.87 min,P0.01）.The intervention group had significantly higher severity and longer duration of epileptic seizure than the model group of young rats（14.25±5.82 min vs 10.17±6.73 min,P0.05）.Compared with the control groups,A1R mRNA and protein expression in the both model groups and the intervention group decreased significantly（P0.05）,showing the most decrease in the intervention group and the least decrease in the model group of adult rats（P0.05,P0.05）.Compared with the control groups,MDA content in CSF in the both model groups and the intervention group increased significantly（P0.05）,showing the most increase in the intervention group and the least increase in the model group of adult rats（P0.05,P0.05）.Conclusion Different degrees of MDA content increase and A1R expression decrease may be one of the reasons for the epileptic seizure difference between young and adult rats.