不同强度40s重复5次+Gz暴露后脑缺血恢复期大鼠学习记忆功能的变化

Effects of repeated (40 s×5) +Gz exposures on learning and memory of rats during post-ischemic recovery

目的:探讨短时重复+Gz暴露脑缺血恢复期大鼠学习记忆功能的改变.方法:将24只雄性SD大鼠随机等分为对照组、+6Gz/40s×5(+6Gz)组和+10Gz/40s×5(+10Gz)组.观察不同+Gz作用后1wk大鼠学习能力的变化.结果:旷场反应中,+6Gz组在暴露后即刻总得分较对照组显著降低(P<0.01);+10Gz组在0d中央格停留时间和总得分较对照组显著延长(P<0.01);与+6Gz组比较,+10Gz组中央格停留时间在0,4d显著延长(P<0.05).在辨别性学习能力测试中,+6Gz组正确反应次数和反应时在各时间点与对照组均无明显差异;+10Gz组正确反应次数在2d较对照组显著降低(P<0.01),反应时在0,2d显著延长(P<0.05或P<0.01);与+6Gz组比较,+10Gz组的正确反应次数在0,2d时显著降低(P<0.05或P<0.01),反应时在0,2,4d显著延长(P<0.05或P<0.01).在被动回避反应中,与对照组比较,+6Gz和+10Gz组各项指标均无显著性改变.结论:40s×5+10Gz重复暴露导致学习能力暂时性降低.

AIM： To explore the effects of different repeated （40 s× 5 ） ＋ Gz exposures on learning and memory in rats during post-ischemic recovery. METHODS： Twenty-four male SD rats were randomly divided into 3 groups： control group（ C）, ＋ 6 Gz/ 40sx5 group （ ＋6 Gz）, and ＋10 Gz/40 s×5 group （ ＋10 Gz）. Changes of learning and memory performance in rats were measured during 1 week after ＋ Gz exposure. RESULTS： In the open field test, compared to control group, summation of crossing and rearing（SCR） in ＋ 6 Gz group declined significantly at 0 d （P 〈0.01 ） ; SCR in ＋ 10 Gz group declined significantly at 0 d （ P 〈 0.01 ）, and time stay in center grille （ TSC ） increased significantly at 0 d （P〈0.01） ; compared to ＋6 Gz group, TSC in ＋ 10 Gz group increased significantly at 0 and 4 d（P 〈0.05）. In Y-maze test, compared to control group, there were no apparent changes of either right reaction number（RR） or time of reaction （TR） in ＋6 Gz group at all time points; RR in ＋ 10 Gz group decreased significantly at 2 d （ P 〈 0. 01 vs control group）, and TR increased significantly at 0 and 2 d （ P 〈 0. 05, P 〈 0.01 vs control group） ; compared to ＋ 6 Gz group, RR at 0 and 2 d, TR at 0, 2 and 4 d in ＋ 10 Gz group changed significantly （ P 〈 0. 05, P 〈 0. 01 ）. In passive avoidance test, there were no apparent changes of all items in ＋ 6 Gz or ＋ 10 Gz group as compared to control group. CONCLUSION： Repeated （40s × 5 ） ＋ 10 Gz exposures may temporarily impair the learning ability in rats.