运动训练对小鼠脑局灶缺血后大脑皮质胆碱能纤维密度的作用

Effects of physical exercise on the acetylcholinesterase-positive fiber density after middle cerebral artery occlusion in mice

目的研究运动训练对小鼠大脑中动脉闭塞(middlecerebralarteryocclusion,MCAO)后大脑皮质胆碱能纤维密度的影响,探讨适度运动对脑损伤后功能恢复的作用。方法30只雄性C57BL/6J鼠用Bederson的方法,建立MCAO模型。将MCAO后小鼠随机分为运动组和对照组,每组均15只鼠。运动组:跑笼训练共90d;对照组:跑笼固定不转。分别在MCAO后15,45,90d,观察两组小鼠大脑皮质胆碱能纤维密度改变。结果MCAO后15d,两组皮质III缺血侧、正常侧胆碱能纤维密度差异无显著性意义(t=0.9,0.6,P>0.05)V层运动组犤缺血侧(121±15)个,正常侧为(170±18)个犦比对照组犤(171±15)个,(119±13)个犦显著增高(t=3.4,4.6,P<0.05)。45d,运动组在皮质III犤(241±23)个犦、V层犤(223±12)个犦正常侧胆碱能纤维密度比对照组犤(173±15)个,(181±8)个犦显著增高(t=3.5,3.3,P<0.05),缺血侧无明显差异(t=0.9,1.1,P>0.05)。90d,运动组与对照组比较,在正常侧及缺血侧皮质Ⅲ、V层纤维密度均增高(缺血侧t值分别为3.7,3.8,P<0.05;正常侧t=9.5,9.4,P<0.05)。结论运动训练对小鼠MCAO后大脑缺血侧和正常侧皮层胆碱能纤维的轴突发芽及再生有一定促进作用。

Aim To explore the impact of a moderate amount of physical training on the acetylcholinesterase (AchE) positive fiber density in cerebral cortex after middle cerebral artery occlusion (MCAO) so as to investigate the effect of a moderate amount of physical training on functional rehabilitation after brain trauma. Methods Thirty male C57 BL/6J mice were subjected to the Pederson's surgical procedure to produce MCAO and then divided into training 2 groups of 15 mice: training group, trained with voluntary running wheel for one hour every day(6 days per week) for 90 days, and control group, put in a cage with the running wheel fixed constantly.Normal saline and paraformaldehyde were infused into the roots of aorta of 5 mice and then their brains were taken out, fixed and made into coronal slices 15, 45, and 90 days after MCAO respectively.Histochemistry was used to examine the AchE positive fiber density in the cerebral cortex.Results There were no difference in AchE positive fiber density in III layers in cortex between the training and control groups 15 days after MCAO (t=0.9,1.1,P >0.05). The AchE positive fiber densities of the ischemic side and normal side in layer V of cortex in the training group 15 days after were (121±15)/0.01 mm2 and (170±18)/0.01 mm2 respectively, both greatly higher than those of the control group [(171±15)/0.01 mm2 and (119±13)/0.01 mm2 respectively, t=3.4 and 4.6, both P< 0.05]. 45 days after MCAO, the AchE positive fiber densities in layers III and V of cortex in the normal side of the training group were (241±23)/0.01 mm2 and (223±12)/0.01 mm2 respectively, both significantly higher than those of the control group (173±15)/0.01 mm2 and (181±8)/0.01 mm2, t=3.5 and 3.3, both P< 0.05. However, the AchE positive fiber densities in layers III and V of cortex in the ischemic side were not significantly between the 2 groups (t =0.9 and 1.1, both P >0.05). 90 days after, the AchE positive fiber densities in the two sides of layers III and V of cortex of the training group were significantly higher than those of the control group (ischemic side:t= 3.7, 3.8,P< 0.05;normal side:t =9.5, 9.4, P< 0.05).Conclusion Physical training promotes the germination and regeneration of cortical cholinergic fibers in the normal and ischemic sides of cerebral hemispheres of mice after MCAO.