Effects Of A Bout Of Eccentric Exercise And Soy Hydrolyzed Peptides Supplementation On Histological And Ultrastructural Injury Of Skeletal Muscle In Rats--A Study Of Several Factors On Their Possible Mechanisms

Effects of a Bout of Eccentric Exercise and Soy Hydrolyzed Peptides Supplementation on Histological and Ultrastructural Injury of Skeletal Muscle in Rats------A Study of Several Factors on Their Possible MechanismsExercise-induced skeletal muscle injury, the histological and ultrastructural changes of skeletal muscle, occurred after an intense or/and long-term training. From morphological and metabolic aspects, this test is to probe into the mechanisms of the protection of soy hydrolyzed peptides (SHPs) intake against skeletal muscle injury following a high intensity exercise and promotes the repair function as rapidly as possible. The objective of this research is aimed at exploring an effective ergogenic aid.This research consists of two sections. Part Ⅰ: Effects of SHPs supplementation on small intestinal morphology and nitrogen absorption in ratsMale Sprague-Dawley rats were randomly divided into three groups as placebo, isolated soy protein (ISP) and SHPs. After one-week meal adaptation, all animals underwent metabolic test separately.The results showed apparent digestibility, nitrogen retention rate and nitrogen balance increased remarkably, after SHPs supplementation; the activity of amino peptidase and the content of small intestinal epithelial protein enhanced markedly after SHPs ingestion; and the small intestinal morphological indexes ameliorate evidently, such as the mucosal thickness, the villous height, the crypt depth and the villous surface area. So the crypt cell proliferation and the small intestinal gland developed, the nitrogen digest ion and absorption of small intestine raised (p<0.05).Part Ⅱ: Effects of a bout of eccentric exercise and SHPs supplementation on skeletal muscle ultrastructure injury in rats150 Male Sprague-Dawley rats were randomly divided into 15 groups as placebo, ISP, SHPs supplemented and exercise or not. During one-week meal adaptation, Animals in control and experimental groups were fed 2ml beverage containing 15% SHPs, 15% ISP and placebo, respectively. After one-week meal adaptation,Rats ran 120 minutes at speed of 20±1m /min and -16°. The results showed that activities of serum creatine kinase (CK) and lactate dehydrogenase (LDH) increased significantly following a bout of eccentric exercise. The occurrence time of peak serum CK level was immediately after exercise, and the occurrence time of peak serum LDH level was 12hr following exercise. The histological display (HE staining) of skeletal muscle structure changed obviously in 24~48hr after exercise, but the ultrastructure of skeletal muscle changed evidently in 12~24hr following exercise. After ISP or SHPs supplementation, the histological and ultrastructural changes of skeletal muscule alleviated obviously, but the effect of SHPs supplementation on this was more intensified than ISP supplementation.The results showed that the loss of immunostaining for desmin increased following a bout of eccentric exercise, and the percentage of negative cell for desmin was the highest at 12 hr following exercise. The immunostaining for vimentin increased following a bout of eccentric exercise, and the percentage of positive cell for vimentin was the highest at 24 hr after exercise. The loss of immunostaining for desmin decreased in ISP and SHPs supplementation groups. But the effect of SHPs intake was stronger than ISP intake. The immunostaining for desmin increased in ISP and SHPs supplementation groups. However, the effect of SHPs ingestion was more intense than ISP supplementation.The results above-mentioned indicated that:1.The nitrogen digestion and absorption of SHPs increased remarkably more than those of ISP. 2. The histological and ultrastructural adapted-alteration of skeletal muscle is induced after performing intense training. 3.The depolymerization of desmin is possibly one of the mechanisms of skeletal muscle ultrastructural alteration .4. SHPs or ISP supplementation protected against exercise-induced skeletal muscle injury, and there is a stronger tendency of SHPs supplementation...