Estrogen treatment effects on rats soleus muscles' glycogen content, extracellular matrix and cross-sectional area

Abstract

Objective: To evaluate the effects of estrogen treatment of rats' soleus muscles after denervation on glucose metabolism, muscle mass, glycogen content, cross-sectional area and connective tissue density. Methods: Eighteen rats were divided into the following three groups of six animals: control, denervated for 7 days (denervated), and denervated with estradiol treatment for 7 days (denervated and treated). We measured glucose and insulin tolerance, muscle glycogen, mass, cross-sectional area and connective tissue content. Results: The denervated only and the denervated and treated groups displayed a significant reduction in glucose uptake (32% and 53% respectively compared with the control group; p<0.05). Soleus muscle denervation reduced muscle glycogen (0.25 ± 0.03 vs 0.43 ± 0.02 mg/100mg; p<0.05), muscle mass (0.33 ± 0.09 vs. 0.48 ± 0.06 mg/g; p<0.05) and cross-sectional area (1626 ± 352 vs. 2234 ± 349 μm 2 ; p<0.05), and increased connective tissue content (35 ± 7 vs. 10 ± 5%; p<0.05) compared to controls. Estrogen treatment decreased connective tissue density in the denervated and treated group (24 ± 4%; p<0.05) compared to the denervated group. It also prevented alterations on muscle glycogen in denervated and trated group. However, estrogen treatment did not prevent muscle atrophy (1626 ± 352 vs. 1712 ± 319 μm 2 ). Conclusion: Estrogen treatment of rats' soleus muscles after denervation increased muscle glycogen content and minimized connective tissue density increase, but it did not prevent muscle atrophy.