{'fraction_non_alphanumeric': 0.014537107880642693, 'fraction_numerical': 0.009181331293037491, 'mean_word_length': 6.032258064516129, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Evidence that the β2‐adrenoceptor agonist formoterol improves structural and functional regenerative capacity of skeletal muscles from aged rats

We hypothesized that pharmacological stimulation of β2‐adrenoceptors in aged muscles following injury could improve the regenerative capacity. Young and aged rats were daily treated with a subcutaneous injection of β2‐adrenergic agonist formoterol (2 μg/kg) up to 10 and 21 days after soleus muscle injury. While treatment did not increase heart weight, histological cross‐sections of cryolesioned formoterol‐treated muscles from young and old rats evaluated at 10 days showed less inflammatory process and regenerating myofibers with greater caliber when compared to their controls. Formoterol was able to prevent the decrease in tetanic force and augmented protein synthesis in cryolesioned old muscles at 10 days post‐injury. Muscle cAMP levels were increased in cryolesioned formoterol‐treated young muscles but not in cryolesioned formoterol‐treated old muscles. Formoterol induced mTOR phosphorylation in control and cryolesioned muscles from young and old rats. Our results suggest that formoterol improves structural and functional regenerative capacity of regenerating skeletal muscles from old rats by increasing protein synthesis via mTOR activation.