THE EFFECT OF DIFFERENT TRAINING INTENSITIES AND CONSEQUENT DETRAINING ON LEVELS OF SARCOLIPIN AND PHOSPHOLAMBAN IN FAST-TWITCH AND SLOW-TWITCH MUSCLES OF MALE WISTAR RATS

Calcium plays a major role in cellular functions such as transmission, secretion, the activity of fuel enzymes, cell adhesion, and muscle contraction. Disturbance in its cytosolic levels is associated with cellular abnormalities and apoptosis. The purpose of this study was to investigate the effect of different training intensities, and consequent detraining on changes in phospholamban, and sarcolipin, inhibitory proteins involved in the transfer of calcium.

The present research is applied and developmental in terms of purpose and experimental in terms of the method. Thirty-six male Wistar rats (325.66 ± 35.92) were divided into three groups: aerobic training (AE), high intensity interval training (HIIT), and control (CO). The AE and HIIT groups ran on treadmills at speeds of 12 to 15 and 25 to 30 (m/min) for 8 weeks. At the end of eight weeks of training and four weeks of detraining, the samples were killed, and their extensor digitorum longus (EDL) and soleus (Sol) muscles were removed, homogenized, and centrifuged. ELISA test was used to evaluate the content of PLN and SLN proteins. ANOVA, independent t-test, and two-way analysis of variance test (α = 0.05) were used for statistical analysis.

The results of the study showed that there is a significant interactive effect between the exercise intensity and the type of muscle on the content of inhibitory proteins, phospholamban (P = 0.008), and sarcolipin (P = 0.001). In addition, after four weeks of detraining, interactive effect between muscle type and background of training on phospholamban density (p = 0.002) was observed.

It seems that AE exercises in slow-twitch muscles cause more reduction in inhibitory proteins. It also increases the level of inhibitory proteins, especially in the muscle, which reduces the calcium transfer rate.