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目的生酮饮食是一种高脂、低蛋白和低糖饮食。它的抗痫作用早已明确,但其抗痫机制至今不明。本研究试图从海马突触重建和GLUR5、GLUR6 MRNA表达两方面初步探讨生酮饮食的可能抗痫机制。方法以海藻酸(KAINIC ACID,KA)点燃的雄性SD大鼠(P28)为研究对象,经正常饮食和生酮饮食喂养8周。通过行为学检测、 TIMM’S染色和尼氏染色,观察经不同饮食处理的动物海马苔藓纤维发芽(MFS)和神经元损伤情况,及其癫痫行为和空间学习、记忆功能的变化;经RT-PCR法检测海马GLUR5、GLUR6 MRNA的表达。结果 KA致痫后生酮饮食组动物自发性反复惊厥的次数为(1．40±1．03)次明显少于正常饮食组(7．36±3．7)次。在水迷宫检测中,各组动物找到平台的潜伏期随着测试进行明显缩短(F=33．93,P<0．001),但各处理组间潜伏期却无显著差异(F= 1．24,P=0．32)。KA致痫大鼠海马齿状回内分子层异常TIMM’S染色颗粒的平均A值均显著高于非致痫组,但生酮饮食组和正常饮食组间则无明显差异;各组动物CA3区锥体细胞层及始层的TIMM’S染色颗粒以及海马门和CA1、CA3区神经元的平均A值未见明显差异。KA致痫后生酮饮食组大鼠海马GLUR6 MRNA(48．16±11.53) 明显高于正常饮食组(30．57±15．57,T=2．40,P<0．05),但两组间GLUR5 MRNA却没有显著性差异。结论生酮饮食对KA致痫幼鼠有显著的抗痫作用,并对发育期大脑的空间学习和记忆能力无明显影响。酮食疗法不能抑制KA致痫幼鼠的MFS,它可能通过特有的神经元保护作用,保持大鼠海马GLUR6 MRNA的高表达,抑制苔藓纤维通路的兴奋性传递进而发挥其抗痫作用。
Purpose Ketogenic diet is a high fat, low protein and low sugar diet. Its anti-epileptic effect has long been clear, but its anti-epileptic mechanism is still unknown. This study attempts to explore possible synaptic mechanism of ketogenic diet from the synaptic reconstruction of hippocampus and the expression of GLUR5 and GLUR6 MRNA. Methods Male SD rats (P28) lit by KAINIC ACID (KA) were fed with normal diet and ketogenic diet for 8 weeks. The behavioral tests, TIMM’S staining and Nissl’s staining were used to observe the changes of mossy fiber germination (MFS) and neurons, the changes of epilepsy behaviors, spatial learning and memory function in hippocampal mucosa of animals treated with different diets. By RT-PCR The expression of GLUR5 and GLUR6 MRNA in hippocampus was detected. Results The frequency of spontaneous recurrent seizures in ketogenic diet group after KA-induced seizure was significantly lower than that of normal diet group (1.40 ± 1.03) vs 7.36 ± 3.7. In the water maze test, the incubation period of each platform was significantly shortened with the test (F = 33.93, P <0.001), but there was no significant difference between the treatment groups (F = 1.24, P = 0.32). KA-induced epileptic hippocampal dentate gyms of the anomalous TIMM’s-staining average particle size were significantly higher than non-epileptic group, but the ketogenic diet group and the normal diet group there was no significant difference; CA3 cone There was no significant difference in the average A value of TIMM’S staining granules and the neurons in the hippocampus and CA1 and CA3 area between the somatic and basal layers. Compared with the normal diet group (30.57 ± 15.57, T = 2.40, P <0.05), GLUR6 MRNA (48.16 ± 11.53) in hippocampus of ketogenic diet induced by KA was significantly higher in both groups There was no significant difference between GLUR5 MRNA. Conclusions Ketogenic diet has a significant anti-epileptic effect on young rats with KA-induced seizures and has no significant effect on the spatial learning and memory ability of the developing rats. Ketamine can not inhibit the MFS of KA-induced seizures in young rats. It may maintain the high expression of GLUR6 MRNA in the hippocampus, inhibit the excitotoxic transmission of mossy fiber pathways and exert its antiepileptic effect through its unique neuronal protection.