The purpose of this experimental study was to investigate the effects of topical applications of hyaluronic acid on peripheral nerve scarring and regeneration in an adult rat model. After the right sciatic nerves of 48 rats were transected and immediately repaired, nerves were randomly divided into two groups. Nerves to which were applied hyaluronic acid comprised the experimental group, and nerves to which were applied saline comprised the control group. Perineural scarring was evaluated at 4 and 12 weeks macroscopically and histologically. Nerves treated with hyaluronic acid demonstrated significant reduction in perineural scar thickness (P < 0.05, Student's t-test). Histomorphologic nerve analysis, electrophysiologic studies, muscle mass evaluation, and serial functional walking-track analysis were performed for evaluation of peripheral nerve regeneration at 12 weeks. The results showed better conduction velocities, increased axon-fiber diameter, and faster functional recovery in hyaluronic acid-treated nerves (P < 0.05, Student's t-test). In conclusion, hyaluronic acid appears to be effective in preventing perineural scar formation, resulting in enhancement of peripheral nerve regeneration.

No abstract

We have investigated the effects of the intra-operative application of a combination of hyaluronic acid and amniotic membrane on adhesions in the flexor tendons of a chicken model. We used 144 tendons which were partially divided and then repaired by a modified Kessler technique. There were four test groups: group 1, simple tendon repair, group 2, repair site wrapped with amniotic membrane, group 3, hyaluronic acid injected around the repair site, and group 4, repair site wrapped with amniotic membrane and hyaluronic acid injected within it. At three and six weeks, the extent of the adhesions and the healing of the tendon were evaluated macroscopically and histologically. The range of movement of the toe and tensile strength of the repaired tendons were measured at 20 weeks. The least adhesions were observed in group 4 but no significant difference was found in the healing of the tendons. Overall, the intra-operative application of a combination of hyaluronic acid and amniotic membrane appears to be effective in preventing adhesions of the flexor tendon.

Preliminary data show that HAF enhances peripheral nerve regeneration. The preventive effect of HAF on epineural scarring and the rich content of neurotrophic and neurite-promoting factors possibly contribute to this result.

No abstract