运动对小鼠寿命和脊髓前角神经元形态和数量的影响

EFFECTS OF PHYSICAL TRAINING ON MORPHOLOGY AND NUMBER OF NEURONS IN THE ANTERIOR HORN OF SPINAL CORD AND THE LIFE-SPAN OF MICE

用C_(57)BL/3J小鼠29只,分成运动组(12只),对照组(12只)和青年组(5只)三组.运动组从第6个月起隔天跑转笼2小时,对照组不跑转笼.当这两组小鼠死亡总数达50%时(经过16个月零8天),将两组余下的小鼠(22月龄)全部杀死,取出脊髓腰膨大(L_2)与青年组(6月龄)的相比较.结果表明:运动组与对照组的存活率无显著性差异,P>0.05;老年的小鼠脊髓前角神经元总数比青年组的少,但运动组神经元减少较轻,P<0.05,减少的主要的是小神经元,大、中神经元并没有减少;而对照组神经元减少明显,P<0.01,减少的主要是大、中神经元.在三组随机抽出的大神经元胞体切面面积中,运动组最大,青年组居中,对照组最小,两两比较P均<0.01.实验结果提示:长期适量的运动对小鼠的寿命影响不大,但可能会减轻脊髓前角神经元在衰老过程中的死亡程度,最明显的影响是将运动神经元保存下来.

Twenty--nine C_(57)BL/3J mice were used in this study and divided into exercise,age-matched and young control groups.From six-month old on,the mice in the exercise group were trained with voluntary running wheels for two hours every other day,whereas the mice in the age-matched group were put in the immobilized wheels for the same time.When half of the mice in these two groups died,all of surviving mice,which had undergone a training of 16 months and 8 days and were 22-month old,were killed.The L_2 segment of spinal cord of these mice were removed and compared with that of the six-month-old mice in the young group.The findings in this study suggest that a moderate amount of prolonged physical training has no significant effect on the life-span of the mice,but it may reduce the loss of neurons in the anterior horn of spinal cord in the process of aging,and that a possible mechanism is that physical training protects the motor neurons from loss.