Preservation of denervated muscle form and function by clenbuterol in a rat model of peripheral nerve injury

The effects of clenbuterol in preserving the form and function of muscle after unilateral sciatic nerve division and epineural repair were investigated in a rat model. The drug (a beta (2)-adrenoceptor agonist) was administered daily for six weeks by gastric gavage (10 mug/kg body weight), interrupted every 5 days by a 2 day omission of dosing to avoid drug desensitization. Clenbuterol reduced the loss of wet weight, total protein, muscle fibre cross sectional area and (in part) contractile forces in denervated hindlimb muscles, with most effects lasting until reinnervation. The effects were dependent on muscle type, with slow-twitch oxidative muscle (soleus) and mixed-fibre (gastrocnemius) showing greater sensitivity to the drug than fast-twitch muscle (extensor digitorum longus). Anabolic effects on the contralateral innervated muscles tended to be small. The results suggest a potential for the adjuvant use of selective beta -adrenoceptor agonists in the management of peripheral nerve injuries in humans.