Comparison of efficacy of topical phenytoin with hypericin in second-degree burn wound healing: an experimental study in rats.

Background: This experiment was performed to compare the effects of Phenytoin (PHT) and Hypericin (HP) cream on healing of burn wounds in rats.

Material And Methods: Twenty rats were divided into 3 groups and second-degree burn wounds were created. The burn wounds in the first, second, and third groups were covered twice daily with PHT cream, HP cream, and saline (control), respectively. At the end of days 3, 7, 14, and 21, full-thickness skin biopsies were done for histopathologic and immunohistochemical analyses.

Results: Histopathologic evaluations at the 14th day showed that re-epithelialization scores were greater in the HP group than the PHT group, but on day 21, re-epithelialization scores were higher in the PHT group than the HP group. Collagen content on days 3 and 14 in the PHT group was found to be higher than in the HP group. Well-vascularized granulation tissue on day 7 in the PHT group was higher than in other groups. HP and PHT groups had a significant increase in VEGF and TGF-b expression in burn wound healing area compared to the control group on all days.

Conclusions: Topical application of HP can promote re-epithelialization in burn wounds to shorten the wound healing time for superficial burns. Phenytoin, on the other hand, contributes to healing by increasing vascularized granulation tissue and collagen synthesis through re-epithelialization. The increased VEGF and TGF-b expression following PHT and HP treatment strongly indicate that PHT and HP treatment promotes VEGF and TGF-b production and action in the burn wound area.