The aim of this study was to evaluate the effect of metformin treatment on the muscle mass, fibers area and connective tissue area density in soleus (S) muscle under articular immobilization. METHODS AND RESULTS: Male Wistar rats (250-300g) were divided in 4 groups (n=5): control, treated with metformin, immobilized and immobilized treated with metformin. Immobilization was performed by acrylic resin orthoses on the left hindlimb keeping the ankle in neutral position during 7 days. The animals were euthanatized and the S muscle was dissected and weighed. Samples of its ventral portion were treated for inclusion in paraffin and stained in Hematoxylin-Eosin (H:E). The results were obtained through analyses of the muscular fiber area (images analyzed - Image Pró-plus 4,0), as well as of intramuscular connective tissue by means of planimetry. The statistical analysis was performed by normality test followed by ANOVA and Tukey (p<0.05). Hindlimb immobilization during 7 days promoted significant reduction (p<0.05) of 35% in the muscular mass; 44% (p<0.05) in the fiber area and increase of 216% (p<0.05) in the intramuscular connective tissue. The metformin in immobilized group promoted significant alterations (p<0.05) in the muscular mass. In addiction, it was observed significant increase (p<0.05) of 29.6% in the fibers area and significant reduction (p<0.05) of 67% in the intramuscular connective tissue. CONCLUSION: The metformin treatment minimized the reduction of muscle fibers area, as well as the increase of connective tissue in hindlimb immobilized muscle. These results suggest that metformin should be used to increase fast muscle recovery after hindlimb immobilization.
disuse atrophy; metformin; rehabilitation
