Related Experiment Videos
Susceptibility of mouse skeletal muscles to exercise injuries
Abstract:
The susceptibility to exercise-induced myopathy was studied by histological and biochemical methods in various skeletal muscles of mice 3-4 days after a single bout of prolonged running. The degree of exercise injuries varied greatly in different muscles. Soleus and the red deep parts of quadriceps femoris were the most severely affected muscles. Extensive or scattered necrosis of muscle fibers was associated with focal inflammation and a five- to nine-fold increase in the activity of beta-glucuronidase in these muscles. Slight necrotic changes and a two- to three-fold increase in the activity of beta-glucuronidase were observed in tibialis anterior, plantaris, and the red deep parts of gastrocnemius. A statistically significant increase in beta-glucuronidase activity was also observed in the white distal part of quadriceps femoris, biceps femoris, gracilis, extensor digitorum longus, and peroneal muscles but necrotic lesions were infrequent in these muscles. The degree of exercise injuries is probably affected by the different recruitment of muscles during running and by the anatomical location of muscles in separate compartments, which could expose them to different levels of ischemic compression by postexercise edema.
Insights
Prolonged running causes exercise-induced myopathy, with soleus and quadriceps muscles most affected. Muscle damage and inflammation correlate with increased beta-glucuronidase activity, indicating cellular injury.
Area of Science:
- Exercise physiology
- Skeletal muscle biology
- Pathology
Background:
- Exercise can induce skeletal muscle damage, known as exercise-induced myopathy.
- The extent and severity of this damage can vary significantly between different muscle groups.
- Understanding these variations is crucial for optimizing training and recovery.
Purpose of the Study:
- To investigate the susceptibility of various skeletal muscles to exercise-induced myopathy after prolonged running.
- To correlate histological and biochemical markers of muscle injury with specific muscle groups.
- To explore potential factors influencing differential muscle susceptibility.
Main Methods:
- Histological examination of muscle fiber necrosis and inflammation.
- Biochemical analysis of beta-glucuronidase activity as a marker of cellular damage.
- Comparison across multiple skeletal muscles in mice following a single bout of prolonged exercise.
Main Results:
- Soleus and red deep quadriceps femoris showed the most severe muscle fiber necrosis and inflammation.
- These severely affected muscles exhibited a 5- to 9-fold increase in beta-glucuronidase activity.
- Other muscles like tibialis anterior and gastrocnemius showed milder changes, while some had increased enzyme activity without significant necrosis.
Conclusions:
- Muscle susceptibility to exercise-induced myopathy is highly variable and depends on the specific muscle group.
- Differential recruitment patterns during exercise and anatomical factors like ischemic compression may contribute to injury severity.
- Increased beta-glucuronidase activity serves as a sensitive indicator of exercise-induced muscle damage.