Effects of low dose of gamma knife irradiation on the expression of NMDA receptor subunits in the cortex and hippocampus of epileptic rats / 中国神经精神疾病杂志

ABSTRACT

Objective To investigate the effects of low dose of gamma knife irradiation on the expression of N-methyl-D-aspartate (NMDA) receptor subunits in cortex and hippocampus of epileptic rats. Methods The rats were randomly divided into 4 groups: control group, GK group, pentylenetetrazole (PTZ) group and GK+ PTZ group. The rats were injected intraperitoneally with PTZ to establish the epileptic models. Gamma knife irradiation was performed on bilateral frontal cortex of rats at a peripheral dose of 15Gy. After irradiation, the changes of the seizure and behaviors were observed and recorded. The rats were killed on the 12th week after irradiation, Immunohistochemstry and western blotting were used to detect the relative expression levels of NMDAR subunits (NR1, NR2A, and NR2B) in the cortex and hippocampus. Results There were no epileptic seizures in the control group and the GK group. Compared with the PTZ group, the epileptic seizures of rats in the GK+PTZ group were significantly reduced after low dose gamma knife irradiation (P<0.05). Compared with control group, the protein expression levels of NR1, NR2A and NR2B in the PTZ group increased significantly in the cortex and hippocampus, and so were the positive neurons and their average absorbance value (P<0.05). Compared with PTZ group, the protein expression levels of NR1, NR2A and NR2B of the GK+PTZ group decreased remarkably in the cortex and hippocampus (P<0.05). Protein expression levels of NR1, NR2A and NR2B were not significantly different between control group and GK group (P＞0.05). Conclusion Epileptic rats exhibited an increase in the protein expression levels of NR1, NR2A and NR2B in the cortex and hippocampus while low dose of gamma knife irradiation can decrease expression levels of NMDA receptor subunits in the cortex and hippocampus of epileptic rats, which might represent a possible mechanism underlying the therapeutic effects of gamma knife irradiation on epileptic seizure.