Related Experiment Videos
Aging and stress-induced changes in complement activation and neutrophil mobilization
J G Cannon1, M A Fiatarone, R A Fielding
1US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|June 1, 1994
Summary
Eccentric exercise triggers inflammation and muscle damage, with older adults showing reduced neutrophil mobilization and creatine kinase (CK) release. This suggests an age-dependent inflammatory response to muscle injury.
Area of Science:
- Exercise Physiology
- Immunology
- Gerontology
Background:
- Eccentric exercise, involving muscle lengthening under tension, causes muscle damage, soreness, and enzyme release.
- Inflammatory responses, including complement activation and neutrophil mobilization, are implicated in muscle repair following injury.
Purpose of the Study:
- To investigate age-dependent differences in complement activation and neutrophil mobilization after eccentric exercise.
- To determine the association between these inflammatory responses and plasma creatine kinase (CK) levels, a marker of muscle membrane integrity.
Main Methods:
- Twelve older (61-72 yr) and nine younger (20-32 yr) adults performed 45 minutes of eccentric exercise (downhill running or resisting a motor-driven ergometer).
- Plasma des-Arg-C3a (complement activation marker), circulating neutrophils, and plasma CK levels were measured immediately, 4-6 hours, and 24 hours post-exercise.
Main Results:
- All subjects exhibited increased des-Arg-C3a, neutrophils, and CK post-exercise.
- Peak neutrophil increases correlated with des-Arg-C3a, and peak CK increases correlated with neutrophil counts.
- Older adults showed significantly smaller increases in neutrophils and plasma CK compared to younger adults.
Conclusions:
- Muscle injury from eccentric exercise involves a sequential inflammatory cascade, with complement activation preceding neutrophil mobilization and subsequent CK release.
- Neutrophil mobilization, but not initial complement activation, is diminished in older adults following eccentric exercise.
- These findings highlight age-related alterations in the inflammatory response to muscle stress and injury.