The rehabilitating effects of running exercise on the decreased skeletal muscle due to low protein diet.

以大鼠肌肉为实验对象，研究了自由跑对低蛋白饮食引起的肌肉萎缩的康复作用。将断乳雌性大鼠随机分为4组：安静对照组（SP/C）、运动组（SP/E）、安静对照组（LP/C）和运动组（LP/E）。允许大鼠自由进食和饮水。将运动大鼠放置在钢笼中，从一开始就可以自由接近跑步轮。7周龄时，LP组以低蛋白饲料替代SP饲料。3周后取腓肠肌、比目鱼肌（SOL）、趾长伸肌（EDL）称重。硝酸处理后，在解剖显微镜下通过轮廓投影仪计数肌肉纤维数量。纤维面积由图像处理系统测量。在10.8、4.5和4.3 ℃预孵育后，用肌球蛋白ATP酶法测定纤维组成（I、IIA、IIB型）。 关于我们 g体重减轻，引起心脏和骨骼肌的显著重量减轻。LP/E组虽然跑步活动量降低到SP/E组的1/3-1/2，但运动仍能显著增加肌肉重量，对骨骼肌重量的恢复有效。蛋白质缺乏会导致肌纤维数量和大小的减少，尤其是在1型中。然而，运动抑制了纤维尺寸和数量的减少，肌肉重量恢复到对照水平。因此，主要是I型SOL响应于低蛋白质摄入和运动，而不是主要的II型EDL。得出的结论是，在低蛋白质摄入量的肌纤维的数量和面积的减少被抑制，通过运行的运动，肌肉可以恢复到正常。这些结果表明，运动可能是巴布亚新几内亚高地人对蛋白质缺乏的适应机制的一个重要因素，尽管蛋白质摄入量低，但他们的体格非常强壮。少

The rehabilitating effects of voluntary running on muscle atrophy due to a low protein diet were studied in rat muscle. Female weanling rats were randomly assigned to four experimental gouts : sedentary control on standard protein diet(SP/C), exercising on SP diet(SP/E), sedentary control on low protein diet (LP/C), exercising on LP diet(LP/E). Rats were allowed ad libitum access food and water. Exercising rats were placed in steel cages free access to running wheels from the beginning. Low protein diet replaced SP diet in LP groups on 7 weeks of age. Three weeks later, gastrocnemius, soleus(SOL), extensor digitorum longus(EDL) muscles were dissected and weighed. Fiber number of muscle was counted through profile projector under a dissecting microscope after nitric acid treatment. Fiber area was measured by an image processing system. Fiber composition (typesI, IIA, IIB) was determined with the myosin ATPase method after pre incubation at 10.8, 4.5, and 4.3.Low protein intake, producin … More g a loss of body-weight, caused a significant weight loss of heart and skeletal muscles. Although running activity of LP/E group was lowered to 1/3-1/2 of that of SP/E group, exercise still increased muscle weights significantly and was effective in recovery of weight of skeletal muscles. Protein deficiency reduced the muscle weight due to the decrease of number and size in muscle fibers, especially in type 1. However, the reductions of fiber size and number were inhibited by exercise and the muscle weight was restored to control level. The recovery of fiber number and size was largely due to that of type I.Thus, predominantly type I SOL responded to low protein intake and exercise rather than predominantly type II EDL.It was concluded that the decrease in number and area of muscle fibers during low protein intake was inhibited by running exercise and the muscle can be restored to normal. These results suggested that exercise may be an essential factor for adaptive mechanism to protein deficiency in Papua New Guinea highlanders, whose physique was very muscular in spite of low protein intake. Less