目的 :观察并探讨不同运动负荷对大鼠心肌VEGF表达及组织学的影响。方法 :5 4雄性SD大鼠 ,随机分为对照组、中等负荷运动组和大负荷运动组 ,进行游泳训练 ,各运动组又分为训练1周 ,训练 3周和训练 5周 3个亚组 ,每组 6只。训练过程中对各组一般情况进行观察和统计。实验组和对照组同期处死 ,取左心室室前壁心肌组织块切片进行HE染色 ,VEGF表达染色 ,组织化学SDH、LDH和AKP ,5’ -N染色 ,并进行电镜观察和图像分析。结果 :对照组中 3周组和 5周组体重增长明显 (P <0 . 0 1 ) ;中等负荷运动组一般情况基本正常 ,3周组和 5周组体重出现下降 (P <0 . 0 5 ) ;大负荷运动组一般情况较差 ,3周组和 5周组体重较 1周组显著下降 (P <0 . 0 5 )。HE染色可见 ,中等负荷训练 3周组和 5周组心肌毛细血管有增多、增粗的趋势 ,大负荷运动 3周组和 5周组心肌细胞核周隙增宽、组织水肿、心肌细胞浊肿。图像分析结果显示 ,与同期对照组比较 ,中等负荷训练 1周组、3周组和 5周组VEGF着色深度 (平均灰度差 )、面积比均有不同程度增加 (P <0 . 0 1 ,P<0 . 0 5 ) ;而大负荷训练组 3周组和 5周组明显降低 (P <0 . 0 5 ,P <0 . 0 1 ) ,且染色分布不均 ,部分区域不着色。酶组织化学和电镜结果显示 ,持续大负荷训练对心肌线粒 Objective: To observe and discuss the effect of different exercise load on the expression of VEGF and histology in rat myocardium. Methods: Fifty-four male Sprague-Dawley rats were randomly divided into control group, moderate-load exercise group and high-load exercise group. The training groups were divided into three groups: training one week, training three weeks and training five weeks , 6 in each group. During the training, the general situation of each group was observed and statistics. The experimental group and the control group were sacrificed at the same period. HE staining, VEGF expression staining, histochemical staining of SDH, LDH, AKP and 5 ’-N were performed on the anterior wall of the left ventricular anterior wall. Electron microscopy and image analysis were performed. Results: The body weight of the 3 weeks and 5 weeks groups in the control group increased significantly (P <0. 0 1). The general load condition of the middle-load exercise group was normal and the body weight of the 3 weeks and 5 weeks groups decreased (P <0.05) ). The general condition of the heavy load exercise group was poor. The body weight of the 3 week and 5 week groups was significantly lower than that of the 1 week group (P <0. 05). HE staining showed that the myocardial capillaries were increased and the thickening trend was observed in the middle-load training groups of 3 weeks and 5 weeks. The myocardial pericytes were enlarged in 3 weeks and 5 weeks after exercise. The results of image analysis showed that compared with the control group at the same period, the VEGF staining depth (average gray difference) and the area ratio of 1 week group, 3 weeks group and 5 weeks group were increased to some extent (P <0. 01, P <0.05). However, the rats in the three-week and five-week training groups were significantly decreased (P <0.05, P <0.01), and the staining distribution was not uniform, and some areas were not colored. Enzyme histochemistry and electron microscopy showed sustained heavy load training on mitochondria