Biomechanical properties of the sciatic nerve following repair: effects of topical application of hyaluronic acid or tacrolimus

Recovery following nerve repair can be evaluated based on electrophysiological and morphological assessments of biomechanical properties. This study compared the effects of topical hyaluronic acid (HA), tacrolimus (FK-506) or saline administration on the biomechanical properties of the sciatic nerve at 12 weeks after nerve repair. Materials and Methods: Eighteen male European rabbits (Oryctolagus cuniculus) (weight from 2.5 to 3 kg) were randomly assigned to one of the following experimental groups (six animals per group): Saline, HA, or FK-506. The non-transected left leg was used as a control group (eighteen sciatic nerves). Biomechanical assays were performed and statistically analyzed. Results: The average maximal load, elastic limit load, maximal stress, and elastic limit strain of the control group were significantly different (P < 0.001) from those of all three experimental groups. Moreover, the other examined parameters (i.e., maximal displacement, elastic limit stress, and maximal strain) were significantly different between the control group and all three experimental groups (P < 0.0001). However, no significant differences in any of the biomechanical parameters were observed between the experimental groups (P > 0.05). At 12 weeks after nerve repair, Saline, HA, and FK-506 groups displayed average maximal stress values that were 72.6%, 77.38%, and 73.8% of those in the control group (100%), respectively. Conclusion: The biomechanical properties of the HA and FK-506 groups were similar to those of the saline group at 12 weeks after nerve repair.