Temperature changes during and after eccentric contractions and its effect on force and desmin loss in rat.

The typical features of eccentric exercise-induced muscle damage is prolonged loss of muscle strength and the most rapid structural change in the fibers is loss of immunostaining for the intermediate filament protein, desmin. In this study isolated perfused rat muscle was used to examine the direct effect of temperature changes on the eccentric contraction-induced force and desmin loss. The left medial gastrocnemius muscle was separated and the entire lower limb was transferred into a prewarmed (35°C) organ bath. Temperature was adjusted to 31 or 39°C during and after eccentric contractions. Maximal isometric force and desmin loss were measured after 15 isometric or eccentric contractions. According to our data, organ bath temperature changes during or after eccentric contractions had no significant effect on force loss. However, a strong correlation between desmin loss and temperature changes during (r = 0.886, P< 0.05) and a weak correlation between desmin loss and temperature changes after (r= 0.699, P<0.05) eccentric contractions was observed. Our results suggest that cooling during eccentric contractions may decrease desmin loss but temperature changes after eccentric contractions have no effect on desmin loss.