Gender differences in skeletal muscle fibre damage after eccentrically biased downhill running in rats

Abstract

Specific antibodies against structural proteins of muscle fibres (actin, desmin, dystrophin) and extracellular matrix (fibronectin) were used to study the effect of eccentrically biased downhill running exercise (13,5 degrees, 17 m min(-1), 130 min) on the magnitude and properties of myofibre injury in the quadriceps femoris muscle of male and female rats. Muscle beta-glucuronidase activity, a quantitative indicator of muscle damage, showed clearly smaller increase in female than in male rats during the 4-day period following exercise. A similar course of histopathological changes was observed in both sexes, although females showed slower and less marked changes than males. In males, discontinuous or even lost submembrane protein dystrophin staining was observed in some swollen fibres immediately after exercise, before the loss of desmin and staining of disorganized actin, i.e. before the disruption of the cytoskeletal system and the contractile apparatus. The observation that no dramatic changes in the microarchitecture of the muscle fibres were detected immediately or even 6 h after the exercise in females compared with males may indicate that the sarcolemma of the females might be strengthened against membrane damage by a still unknown stabilizing compound.

Estrogen supplementation failed to attenuate biochemical indices of neutrophil infiltration or damage in rat skeletal muscles following ischemia

“…There were no consistent gender differences noted in any of the results. These results are in contrast to the reported effectiveness of estrogen supplementation in attenuating indices of neutrophil infiltration following running exercise in male and ovariectomized female rats (Tiidus and Bombardier, 1999;Tiidus et al, 2001), and in the reported attenuation of indices of muscle damage and bGLU activity following downhill running in male versus female rats (Komulainen et al, 1999). The results also contrast most (i.e., Node et al, 1997;Squadrito et al, 1997;Zhai et al, 2000) but not all studies (Grist et al, 2002), which suggest a reduction on indices of neutrophil infiltration and damage with estrogen supplementation following ischemia in cardiac muscle.…”

“…Komulainen and colleagues (1999) and Amelink and colleagues (1991) have reported female rats as having attenuated indicators of muscle damage following running exercise when compared to male rats. These differences have been attributed to the potential influence of estrogen (Komulainen et al, 1999). However, gender differences in muscle damage indicators have not been demonstrated consistently following exercise in humans (i.e., Stupka et al, 2000;Clarkson and Sayers, 1999).…”

“…Indices of skeletal muscle damage also may be influenced by estrogen or gender (Amelink et al,1991;Komulainen et al, 1999). Ischemia-reperfusion induced damage and post-injury recovery in cardiac muscle has been reported to be improved by estrogen supplementation in most (i.e., Node et al, 1997;Squadrito et al, 1997;Zhai et al, 2000) but not all (Grist et al, 2002) studies.…”

The ubiquitin proteasome system in atrophying skeletal muscle: roles and regulation

“…The loss of estrogen seen in ovariectomized mice leads to progressive muscle atrophy (45). Estrogens may help stabilize membranes (115), act as antioxidants (102,103), and thereby protect from muscle damage and inflammation (47,108). However, others have shown estrogens to be negative regulators of muscle mass.…”

Gender Differences after Downhill Running for Voluntary Isometric Contractions of Knee Extensor Muscles using Surface EMG

“…Several studies examined the susceptibility for eccentric exercise between males and females in rats (22,23) and humans (4,(24)(25)(26). Downhill running caused larger increases in serum levels of skeletal muscle proteins and enzymes in males than in females, probably due to an involvement of a larger muscle mass in males (10).…”