A basic study of skeletal muscle damage : Relationship between free radical and muscle damage following weight-lifting exercise.

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 10680051
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 体育学
• Research Institution: Tokai University
• Principal Investigator: SHIRAISHI Takemasa Tokai University School of Medicine, Associate Professor, 医学部, 助教授 (90096230)
• Co-Investigator(Kenkyū-buntansha): UCHIYAMA Shuichi Tokai University School of Physical Education, Associate Professor, 体育学部, 助教授 (80256164) ; TAMAKI Tetsuro Tokai University School of Medicine, Associate Professor, 医学部, 講師 (10217177)
• Project Period (FY): 1998 – 2000
• Keywords: weight-lifting / free rdical / muscle damage / ischemia / blood occlusion / GPx

Research Abstract

Rat weight-lifting model (Tamaki T.et al, Med Sci Sports Exerc) was used to determin a relationship between free radical and muscle damage following weight-lifting exercise including mechanism of the muscular blood occlusion. Rubber band was attached to the inguinal of rat hindlimb to make an avascularization during weight-lifting exercise (occlusion training : OT) and compared normal weight-lifting condition (NT). Results were as follows : 1) an ability of weight-lifting was reduced 1/4 in the OT than NT rats. 2) Subcutaneous hemorrhage was also apparent in the OT rats. 3) Muscle fiber ruptures that mechanichally induced by the normal weight-lifting condition were hardly observed in the OT rats. 4) However, blood CK activity (good index for muscular dameg) was signifcantly increased in both OT and NT rat 30-60 min after the exercise. This increase in CK activity lasted for more than 3h only in the OT rats, representing muscle fiber damage was occurred by the different mechanism from w eight-lifting induced mechanical damages. Level of anti-oxidant enzyme (GPx) in the muscle tissues were elevated immediately after the exrcise in both OT and NT group, however, elevated level was lasted for more than 3h only in the OT group simmilar to the tendency of blood CK activity. Thus, the muscle damage that occurred in the OT rats was closely related event of the appearance of free radical in the muscle. The quantitative analysis of haemoglobin (Hb) oxygenation during weight-lifting exercise using near-infrared spectroscopy was also performed. Result showed that at the beginning of the exercise, rapid increase in of deoxy-Hb and decrease of oxy-Hb were observed. In addition, total-Hb gradualy increased during exercise, representing the restriction of venous blood out flow but not of arterial in flow was occurred in the musculature. These results corresponded to the condition of blood occlusion. These tendencies showed that blood occlusion and re-flow was repeated in the weight-lifting exercise. In addition, these tendencies were accelerated in the OT rats. Thus, it was suggested that the muscle damage of OT rats were induced by the free radical which caused by the repeated blood occlusion and re-flow during weight-lifting exercise.