Local Administration of L-Arginine Accelerates Wound Closure

Objective(s) The process of wound healing involves tightly integrated events including inflammation, granulation tissue formation and remodeling. Systemic administration of L-arginine promotes wound healing but its global side effects are undesirable. To confine the action of L-arginine at the site of injury, we tested the effects of local administration of L-arginine on the healing of excisional wound in the rat. Materials and Methods Full thickness excisional wounds were generated on the dorsum of adult male rats. The test wounds received 200 μm or 400 μm of L-arginine on day 3 and 5 post-wounding. Normal saline was injected into the sham wounds which were otherwise treated as the test wounds. Control wounds remained unmanipulated. The wound size was monitored daily by imaging. To determine the rate of wound closure, wound images were scanned and the rate of size reduction was analyzed and quantified by ScnImage software. The repaired tissues were harvested on day 12 post-wounding. The tissue sections were prepared and stained for microscopic examination. Results Wounds treated with L-arginine showed a significant increase in the rate of wound closure. The morphology of basal keratinocytes was altered, and the thickness of neoepidermis was markedly reduced in the wounds treated with L-arginine. Both tested dose of L-arginine were equally effective. Conclusion Local administration of L-arginine accelerates wound closure and has profound effects on keratinocytes performance during the process of healing. Therefore, it can be potentially used for treatment of skin disorders, in particular, those characterized by hyperkeratosis.