RESUMEN
Objective To investigate the changes of calmodulin kinase Ⅱ (CaMK Ⅱ) and cAMP responsive element binding protein(CREB) expressing in primary cultured hippocampal neurons and its relationship with learning and memory deficit after 2000 μW/cm2 electromagnetic radiation.Methods Primary cultured hippocampal neurons in vitro were randomly divided into normal control group,sham-radiated group,and 1 h/d,2 h/d,3 h/dradiation groups.The neurons in the radiation groups were received microwave exposure of 2000 μW/cm2.The change of CaMK Ⅱ and CREB protein in hippocampal neurons of each group of rats were measured with western blot,and the expression of CaMK Ⅱ and CREB mRNA in hippocampus were determined by RT-PCR.Results Compared with control group((0.78 ± 0.07),(0.62 ± 0.12)),the expression of CaMK Ⅱ protein (1 h/d(0.59 ±0.05),2h/d(0.44 ±0.08),3h/d(0.18 ±0.04)) and its mRNA(1h/d(0.41 ±0.08),2h/d(0.34 ±0.04),3h/d(0.24 ±0.02)) was obviously decreased (P＜0.05).Compared with control group((0.69 ±0.10),(0.80 ±0.12)),the expression of CREB protein(1h/d(0.49 ±0.05),2h/d(0.4 ±0.04),3h/d(0.17 ±0.03))and its mRNA (1 h/d (0.68 ± 0.11),2h/d (0.53 ± 0.08),3h/d (0.30 ± 0.03)) was obviously decreased after radiation(P＜0.05).Conclusion Electromagnetic radiation of 2000 μW/cm2 exposure could weaken the learning and memory abilities of rats and the decreases in the expression of CaMK Ⅱ and CREB protein and their mRNA in hippocampus may be involved in the pathophysiological process of learning and memory deficit.
RESUMEN
Objective To evaluate the effects of electromagnetic irradiation of 2000 μW/cm2 exposure on mRNA and protein expression levels of immunoreactive protein and mRNA of NMDAR1 in rats hippocampal,and to explore the impaired mechanism of electromagnetic irradiation on learning and memory.Methods Rats were randomly divided into normal control group, sham-radiated group, and 1 h/d, 2 h/d, and 3 h/d radiation groups.The rats in the radiation groups were fixed and recieved microwave exposure of 2000 μW/cm2, then their learning and memory abilities were tested by Morris water maze experiment, the change of NR1 protein in hippocampal neurons of each group of rats was measured with immunohistochmistry and western blot techniques, and the expression of NR1 mRNA in hippocampus was determined by RT-PCR.Results In the water maze test,compared with the normal control group (8.8 ± 1.66 ), the escape latency of three radiated groups rats ( 1 h/d ( 12.29 ±1.36) s,2 h/d ( 17.99 ±2.25) s,and 3 h/d (24.66 ±5.56) s) were significantly longer (P＜0.05).In the radiation group,the hippocampal neurons of rats showed evident reduction in the ratio of NR1 positive cells,irregular,and arrayed in disorder.Moreover,compared with the normal control group ( (0.70 ±0.11 ), (0.68 ±0.11 ) ) ,the expession of NR1 protein ( 1 h/d (0.122 ±0.026) ,2 h/d (0.102 ±0.023) ,and 3 h/d (0.060 ± 0.009) ) and its mRNA ( 1 h/d (0.46 ±0.07) ,2 h/d (0.35 ±0.05) ,and 3 h/d (0.12 ±0.02) ) in hippocampal neurons was significantly decreased (P＜0.05).Among the indicators, there was no significant difference between sham-radiated group and normal control group.Conclusions Electromagnetic irradiation of 2000 μW/cm2 exposure can impair the learning and memory abilities of rats possibly through a mechanism correlated with the lower expression of NR1 protein and its mRNA in hippocampus.