Effects of acetylo-L-carnitine in end-to-side neurorrhaphy: a pilot study

End-to-side (ETS) nerve repair allows for target-muscle reinnervation, with simultaneous preservation of donor-nerve function. Acetyl-L-carnitine (ALCAR) was shown to enhance axonal sprouting in early regeneration following transection and repair of the sciatic nerve in rodents. The purpose of this article was to determine the ability of ALCAR to enhance axonal regeneration in an ETS rodent model.

The right musculocutaneous nerve in 16 adult male Sprague-Dawley rats was transected to induce biceps muscle paralysis. The distal stump was then coapted by ETS neurorrhaphy through a perineurial window to the ipsilateral median nerve. Experimental groups received ALCAR for 1, 2, 3, and 4 weeks whereas controls received placebo.

Weekly postoperative behavioral evaluations revealed increased functional return over control but the difference was not significant. Potentials from biceps were recorded from the third postoperative week in the experimental group and from the fourth week in the control group. Histomorphometric evaluations revealed higher musculocutaneous nerve axon counts, higher myelin thickness in the fourth postoperative week, and differences in the appearance and the number of motor-end-plates in the biceps in experimental versus control group.

Intraperitoneal administration of ALCAR can expedite biceps muscle recovery in an ETS model by increasing the rate of axonal regeneration. Despite the morphological changes, no behavioral changes were noted and further studies are needed to confirm clinical efficacy of ALCAR for potential use in the development of therapeutic protocols.