An appraisal of the healing profiles of oral and external (gel) metronidazole on partial thickness burn wounds

Objective: To assess the influence of oral and topical (gel) metronidazole on partial thickness thermal burn wound healing. Methods: Partial thickness burn wounds were produced on dorsum of rats by pouring hot molten wax at 80°C. Oral and two topical gel (MGEL-1 and MGEL-2) preparations of metronidazole or their corresponding vehicles were administered to different groups of wound bearing animals. The effects of the treatments were compared by periodically observing wound contraction and epithelization and histological features as indicative of the progress of healing. Results: Healing of burn wounds was significantly promoted by oral metronidazole (p<0.01) and the gel base of MGEL-2. In contrast, the MGEL-1 significantly (p<0.05) depressed the epithelization process while its base was without effect, indicating that topical metronidazole retards healing. The effect of MGEL-2 appeared to be an algebraic sum of pro- and anti-healing effects of the base and drug respectively more in favour of the base (p<0.05). Conclusion: Metronidazole orally promotes but topically depresses healing of burn wounds. The latter effect can be reversed if the base has pro-healing property.