RESUMO
PURPOSE: To investigate the effectiveness and to compare the degree of axonal regeneration with the control after the topical application of dexamethasone, hyaluronic acid and amniotic fluid at the repair site of the peripheral nerve. MATERIALS AND METHODS: The left sciatic nerves of 40 adult Sprague-Dawley rats were transected and neurorrhaphy was performed. The nerves were divided into four groups according to the solution applied around the repair site: control group (group 1), 0.3 ml normal saline: experimental groups, 0.3 ml dexamethasone (group 2), 0.3 ml hyaluronic acid (group 3), and 0.3 ml amniotic fluid (group 4). The thickness of the perineural scar tissue, the count of the myelinated nerve fiber and axonal regeneration on the repair site were evaluated electromyographically and histologically 4 and 12 weeks after surgery. RESULTS: The peak amplitude of the compound motor action potential was observed in group 2, at postoperative 4 weeks and group 3 at postoperative 12 weeks. The increase in the number of myelinated nerve fibers was most prominently in group 3 at 4 and 12 weeks after surgery. The degree of perineural scarring was lowest in group 2 at postoperative 4 weeks and in group 3 at postoperative 12 weeks. CONCLUSION: A single dose topical application of Dexamethasone, HA and Amniotic fluid is more effective in preventing perineural scar formation as well as in facilitating the nerve regeneration process in a rat hind-limb model than using saline.