Comparative study on the effects of heated brass bar and scald methods in experimental skin burn in rat

Experimental burn can be inflicted by various means, and each method affects the healing processes. To date, several methods have been developed, but their standardization is difficult. We aimed to compare two experimental methods, heated brass bar, and scalding, to provide an in-depth understanding of their limitations and errors. Scald burn is afflicted by pouring 2.5 cc of boiling water (95 °C) into a firm rubber ring (2 cm diameter) on the dorsal surface of a rat skin for 15 s. The other experimental model is performed by bringing a brass bar (2 cm diameter) heated to 95 °C in boiling water in contact with the surface of the skin for 15 s. The clinical course of healing was evaluated macroscopically for 7 days, and then microscopically. The scald burn produced a uniform wound with the same depth of tissue damage without any marked inflammation and hemorrhage. The scab formation and the extent of granulation tissue, as well as re-epithelialization, were the same in all rats and the lesions healed uniformly. Compared with scald, burns of various depths were induced by the heated brass bar and the burn area did not heal uniformly. Widespread hemorrhage and microabscess were common in this group without any sign of scab formation or re-epithelialization. This study highlights the benefits of scald method in comparison with the heated brass bar.