强化训练对脑缺血再灌注大鼠骨骼肌p-Akt蛋白表达的影响

Effects of intensive training on the expression of p-Akt in skeletal muscles after cerebral ischemia and reperfusion

目的观察不同强度跑台训练对脑缺血再灌注损伤大鼠骨骼肌中磷酸化蛋白激酶B（p-Akt）的表达及运动功能的影响。方法选取符合纳入标准的120只大鼠，按随机数字法分为假手术组、模型组、普通训练组和强化训练组，每组30只。通过线栓法建立大鼠左侧大脑缺血再灌注（MCAO）损伤模型，假手术组不阻断大脑中动脉，不给于跑台训练；模型组大鼠MCAO造模成功后，未给予跑台训练；普通训练组大鼠MCAO造模成功后，每日给予30min的跑台训练（普通训练）；强化训练组大鼠MCAO造模成功后给予每日早晚各1次的30min跑台训练（强化训练）。分别于训练第1、3、7和14天，采用Zausinger六分法评分检测各组大鼠的神经功能情况并加以比较。于实验第3、7和14天三个时间点，每组各取5只大鼠灌注后分别取两侧腓肠肌行苏木素一伊红（HE）染色，镜下观察各组大鼠腓肠肌纤维横截面形态，镜下每个视野取10个轮廓较为完整的肌纤维，计算每根肌纤维平均横截面积及其横截面积维持率。将各组实验第3、7和14天三个时间点剩余的大鼠取患侧腓肠肌，采用WesternBlotting法检测分析其p-Akt蛋白的表达情况。结果①给予跑台训练第1、3和7天后，普通训练组和强化训练组的Zausinger行为学评分差异无统计学意义（P〉0．05）；但跑台训练第14天后，强化训练组行为学评分明显高于普通训练组（P〈0．05）。②跑台训练第3天，各组大鼠腓肠肌横截面积维持率两两比较，差异无统计学意义（P〉0．05）；而在跑台训练第7天和第14天时，假手术组大鼠腓肠肌横截面积维持率[（96．67±2．76）％和（94．34±6．17）％]均明显高于同时间点模型组[（70．35±2．21）％和（64．89±2．45）％]、普通训练组[（78．68±3．46）％和（71．39±5．72）％]和强化训练组[（83．31±2．89）％和（78．78±3．67）％]，且组间差异均有统计学意义（P〈0．05）；而且强化训练组大鼠腓肠肌横截面积维持率均明显大于同时间点的普通训练组（P〈0．05）。③跑台训练第7天和第14天，强化训练组p-Akt蛋白表达水平[（0．749±0．042）和（0．689±0．064）]明显高于普通训练组[（0．578±0．072）和（0．433±0．106）]，且组间差异有统计学意义（P〈0．05）。结论跑台训练可促进p-Akt蛋白的表达；强化训练比普通训练更加有利于p-Akt蛋白的表达，更能防止肌肉萎缩和改善患侧肢体功能。

Objective To observe the effects of treadmill training at different intensities on the expression of p-AKT in rats＇ gastrocnemius muscles after focal cerebral ischemia, and to investigate whether intensive training is beneficial for the recovery of motor function. Methods Left middle cerebral artery occlusion （MCAO） was induced in 120 male Wistar rats using the intraluminal thread method, and they were divided into an MCAO group （no training） , a normal training group （ treadmill training once a day for 30 min） and an intensive training group （ treadmill training twice a day for 60 min） , each of 30 rats. There was also a sham control group with 30 members not given MCAO or training. The four groups were further divided into 3 day, 7 day and 14 day subgroups. Five rats randomly selected from each subgroup were sacrificed for hematoxylin-eosin staining after 4% paraformaldehyde treatment. Neurological function was evaluated using Zausinger scores, and the expression of p-Akt was detected by western blot- ting. Results No significant differences in Zausinger scores were observed between the intensive training group and the normal training group after 1, 3 or 7 days of training. However the average Zausinger score in the intensive training group was significantly higher than in the normal training group after 14 d of treadmill training. After 7 d and 14 d of treadmill training the average cross-sectional area of the gastrocnemius muscles in the sham group was significantly higher than in the other three groups. The average area of the intensive training group was significantly larger than that of the normal training group. The expression of p-Akt in the gastrocnemius was significantly increased in the intensive training group compared with the normal training group in the 7 day and 14 day subgroups. Conclusion Treadmill training can improve the expression of p-Akt in atrophied gastrocnemius muscles caused by MCAO. Intensive training is more effective for the recovery of muscle function.