Effect of in situ delivery of acetyl-L-carnitine on peripheral nerve regeneration and functional recovery in transected sciatic nerve in rat

The repair of peripheral nerve injuries is still one of the most challenging tasks and concerns in neurosurgery, plastic and orthopedic surgery. Effect of acetyl-L-carnitine (ALC) loaded chitosan conduit as an in situ delivery system of ALC in bridging the defects was studied using a rat sciatic nerve regeneration model. A 10-mm sciatic nerve defect was bridged using a chitosan conduit (CHIT/ALC) filled with 10 μL ALC (100 ng/mL). In control group (CHIT), the conduit was filled with the same volume of the phosphate buffered solution. The regenerated fibers were studied 4, 8, 12 and 16 weeks after surgery. The functional and electrophysiological studies confirmed faster recovery of the regenerated axons in ALC treated than control group ( P < 0.05). The mean ratios of gastrocnemius muscles weight were measured. There was statistically significant difference between the muscle weight ratios of CHIT/ALC and CHIT groups ( P <0.05). Morphometric indices of regenerated fibers showed number and diameter of the myelinated fibers in CHIT/ALC were significantly higher than in control group. In immuohistochemistry, the location of reactions to S-100 in CHIT/ALC was clearly more positive than CHIT group. ALC when loaded in a chitosan conduit resulted in improvement of functional recovery and quantitative morphometric indices of sciatic nerve. • Long-term systemic administration of ALC increases the quantity and quality of nerve regeneration after primary nerve repair. • A localized, effective and sustained delivery is crucial for a potentially broader use of ALC. • ALC when loaded in a chitosan tube improved functional recovery of transected sciatic nerve in rat. • This approach could deliver a superiour quality of reinnervation in a shorter period of time.