The effects of stretching on muscle morphometry of ovariectomized rats

Resumo

Introduction: Ageing is responsible for structural alterations, declining of all physiological variables, including range of motion and skeletal muscle function, known as sarcopenia. Objective: The aim of the study was to evaluate the effects of stretching on muscle morphometry in ovariectomized rats. Method: 21 female Wistar rats (12 weeks, 218 ± 22 g) were divided into 4 groups: control (CONTROL, n = 3) intact; ovariectomized and hysterectomized (OH, n = 6); Stretching (STRET, n = 6); ovariectomized and hysterectomized and stretching (OHS, n = 6). The rats were subjected to ovariectomy and hysterectomy. The stretching protocol of the soleus muscle lasted 10 repetitions of 1 minute with 45s interval between each repetition performed 3 times a week for 3 weeks. After 3 weeks, the rats were weighed and the muscles of both hind limbs were removed weighed and analyzed at muscle length; serial sarcomere number; sarcomere length; muscle fiber cross-sectional area (MFCSA) and percentage of connective tissue. Results: The final body weight increased in all groups. The serial sarcomere number of STRET was greater than the OH. The muscle fibers’ cross-sectional area of OHS was higher than CONTROL. Conclusion: It can be concluded that ovariectomy and hysterectomy prevented sarcomerogenesis even when stretching was applied. However, the stretching protocol enhanced muscle trophismof ovariectomized and hysterectomized rats. It might be suggested that longitudinal growth (serial sarcomeres) and radial (ASTFM) are differently regulated by stretching in intact and/or estrogen depleted (ovariectomy and hysterectomy) skeletal muscle.