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目的 观察缺氧缺血 (HI)对新生大鼠远期学习记忆及海马长时程增强发生率的影响 ,探讨缺氧缺血损伤学习记忆的神经机制。方法 选择符合条件的 7日龄Wistar大鼠 49只 ,随机分为正常对照组 (n=1 5)、HI组(n =2 1 )和尼莫通治疗组 (n=1 3)。HI组经结扎左侧颈总动脉、吸入含 8%氧和 92 %氮的混合气体 2h的处理。大鼠经HI处理后给予尼莫通 (1 60 μg/kg,腹腔注射 ,每日 1次 ,共 5d)治疗的为治疗组。正常对照组给予等量生理盐水腹腔注射。至生后 80d左右对各组动物进行Y迷宫分辨学习和记忆能力测试 ,行为实验结束后每组取 5只 ,采用离体脑片电生理技术检测海马LTP的发生率。结果 HI组大鼠Y迷宫中达到学会标准前所需的训练次数为 32 .82± 8.2 2 ,明显多于对照组 (P <0 .0 1 )。 2 4h后的记忆保持率为 59.0 0 %±2 1 .32 % ,显著低于对照组 (P <0 .0 5)。尼莫通可明显提高HI大鼠的学习能力 (P <0 .0 1 ) ,但对记忆无明显效果 ;高频刺激 (HFS)前各组群峰电位 (PS)的平均幅值及平均峰潜伏期之间均无显著性差异 ,HFS后对照组PS平均幅值始终高于HI组和治疗组。HFS后HI组LTP发生率为 30 .8% ,对照组为 57% ,两组间差异显著 (P <0 .0 5) ,治疗组LTP发生率 45.5% ,较HI组有所提高 ,但差异无显著性 (P >0 .0 5)。结论
Objective To observe the effect of hypoxic-ischemic (HI) on long-term learning memory and the incidence of hippocampal long-term potentiation in neonatal rats and to explore the neural mechanism of learning and memory impairment in hypoxic-ischemic injury. Methods Forty nine eligible 7-day-old Wistar rats were randomly divided into normal control group (n = 15), HI group (n = 21) and nimotop group (n = 13). In the HI group, the left common carotid artery was ligated and the mixed gas containing 8% oxygen and 92% nitrogen was inhaled for 2 hours. The rats were treated with nimotop (1 60 μg / kg, intraperitoneal injection once a day for 5 days) treated with HI for the treatment group. The normal control group was given the same amount of saline intraperitoneal injection. At about 80 days after birth, each group of animals was tested for Y-maze discrimination and memory test. Five rats in each group were taken after the behavioral experiment. The incidence of LTP in the hippocampus was detected by electrophysiological techniques in vitro. Results The number of training required to reach the standard was 32.82 ± 8.22 in the Y maze of the HI group, which was significantly more than that of the control group (P <0.01). The memory retention rate after 24 hours was 59.0% ± 2.1.32%, which was significantly lower than that of the control group (P <0.05). Nimodipine significantly improved the learning ability of HI rats (P <0.01), but had no significant effect on memory. Mean amplitude and mean peak (Ps) of peak potentials There was no significant difference between the incubation period, HFS after the control group, the average amplitude of PS is always higher than the HI group and the treatment group. The incidence of LTP in HI group was 30.8% after HFS and 57% in control group (P <0.05). The incidence of LTP in treatment group was 45.5%, which was higher than that in HI group, but the difference was significant No significant (P> 0.05). in conclusion