Changes of lysosomal enzymes activity in the skeletal muscle fibers exposed to endurance exercise.

Purpose: To evaluate the effect of endurance exercise on the activity changes of selected lysosomal enzymes in particular types of rat muscle fibers, occurring by 0-4 days following the trial.

Material and methods: The experiment was performed on 3 month old male Wistar rats with body mass 250 +/- 25 g, exposed to single physical exercise on moving track (speed 17 m x min(-1), decline 0 degree, duration 87.5 +/- 27.5 min). Biochemical analyses were performed on homogenized fast-twitch FTa and FTb (m. gastrocnemius) and slow-twitch ST (m. soleus) muscle fibers of animals sacrificed 2 h (group II), 6 h (III) or 96 h (IV) after exercise and control group. The measurements considered protein concentration and the activities of beta-glucuronidase (beta-GRS), N-acetyl-beta-D-glucosaminidase (NAG), and arylsulphatase A (ASA).

Results: In FTa fibers, ASA and beta-GRS activities were elevated in all the exercised groups, with the most evident changes in animals tested 96 h post trial (group IV), while the peak of NAG activity was demonstrated 2 h after exercise (group II). In contrast, in FTb and ST fibers the levels of all the enzymes studied peaked 96 h after exercise, following the transient decrease in activity.

Conclusions: The present study demonstrated that maximal running exercise, without the eccentric components, affects the activities of lysosomal enzymes in all types of rat muscular fibers. The lack of uniform activity profile for the lysosomal enzymes studied probably reflects the variety of their cellular functions.