Article
Effect of urocortin on skeletal muscle in osteoporotic rats
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Published: | October 23, 2017 |
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Objectives: Aging of society is accompanied by a growing relevance of osteoporosis and osteoporotic fractures, which are expected to increase in incidence by more than 50%. Interestingly, osteoporotic fractures are frequently caused by sarcopenia, an age-related loss of muscle mass, which is an emerging research area due to its therapeutic relevance.
Urocortin is a protein of the corticotropin-releasing factor family and therefore involved in stress response. Importantly, positive effects on metaphyseal bone structure in femora and vertebrae as well as its ability to increase heart muscle mass were demonstrated in vivo. Therefore, we aim to investigate the effect of Urocortin on skeletal muscle in vivo by observing capillary density and fiber diameter in an osteoporotic rat model.
Methods: Sixty Sprague-Dawley rats were divided into five groups out of which four were ovariectomized and one obtained sham-op. Half of ovariectomized rats was treated with Urocortin in different concentrations while one group was treated with estradiol, each for thirty-five days. One group remained untreated. For muscle analyses, the M. gastrocnemius, M. longissimus and M. soleus were isolated. For capillary measurements, PAS staining was carried out and capillaries were counted. In addition, fibre measurements were performed after ATPase staining with counting of fibre area and diameter next to fibre type and relations.
Results and Conclusion: We could demonstrate a positive effect of the protein Urocortin on skeletal muscle in osteoporotic rats. Capillary density, fibre diameter and area of M. soleus were positively influenced by Urocortin, especially in the higher concentration, whereas effects in M. longissimus in diameter and area were similar for lower concentration of Urocortin.
Since osteoporotic fractures are regularly caused by muscular imbalance and resulting lack of coordination, strengthened muscle is outstandingly relevant in preventing fractures. Our results portray Urocortin as a substance that should be considered for future therapeutic concepts regarding osteoporosis.