Effects of resistive exercise and stretching on the soleus muscle of ovariectomized rats

Abstract

ABSTRACT This study analyzed the effects of resistive exercise and/or stretching in the muscle morphology of ovariectomized rats. Seventy-five female Wistar rats (218±22g) were divided into 8 groups: Control (CONTROL, n=5); Ovariectomy/Hysterectomy (OH, n=10): ovariectomized/hysterectomized and then waited 8 weeks for the onset of osteopenia. Stretching (STRET, n=10): manual stretching of the soleus muscle (10 repetitions of 60s), twice weekly; Ovariectomy/Hysterectomy and Stretching (OH+STRET, n=10); Progressive Loading (PL, n=10): 4 sets of 10 repetitions, initial load 50% of body weight, increasing weekly until 70%, three times a week. Progressive Loading and Stretching (PL+STRET, n=10); Ovariectomy/Hysterectomy and Progressive loading exercise (OH+PL, n=10); Ovariectomy/Hysterectomy, Progressive Loading and Stretching (OH+PL+STRET, n=10). Stretching and/or progressive loading were performed for 6 weeks. After 14 weeks, the female rats were euthanized to remove the soleus muscle. The following variables were assessed: body weight; muscle weight and length; number and length of sarcomeres and the muscle fiber cross-sectional area (MFCSA). Comparisons between the groups were performed with ANOVA one-way post hoc Tukey or Kruskall-Wallis (p<0.05). The body and muscle weights of ovariectomized rats submitted to exercise were higher than the intact ones. The OH and OH+PL+STRET increased the muscle length and the serial sarcomere number. OH presented the smallest MFCSA compared to all groups. Ovariectomy/hysterectomy induced sarcopenia, but the exercise's protocols were enough to prevent the loss of MFCSA. The increase in body weight associated to resistive training and stretching enhanced sarcomerogenesis of ovariectomized rats.

Keywords

• Muscle Stretching Exercises
• Musculoskeletal System
• Sarcopenia
• Rats