Burn wound excision is considered necessary to prepare skin for grafting, and the success of graft "take" is thought to be dependent on the vascular supply to the wound. We previously showed that photocrosslinkable chitosan hydrogel containing DMEM/F12 medium (medium-Az-CH-LA) is a biocompatible and biodegradable biomaterial that promotes re-epithelialization and neovascularization. The current study was designed to determine the effect of medium-Az-CH-LA on deep dermal burn. Sixteen male Wistar rats were randomly divided into two groups that were treated with medium-Az-CH-LA (n=5) or a collagen sponge (n=5). Under anesthesia, the dorsal fur was shaved and the skin was exposed to water at 95 degrees C for 10s. After 2h, damaged tissue was removed from the fascia and dressed with medium-Az-CH-LA or a collagen sponge. Specimens were obtained after 2, 4, 6, 8, 12, 16 and 32 days for histological analysis. There was no significant difference in the time required for wound closure between the two groups, but the thickness of the granulation tissue in the medium-Az-CH-LA-treated group was greater than that in the collagen sponge-treated group. Moreover, degradation and neovascularization occurred earlier in the group treated with medium-Az-CH-LA compared with the collagen sponge-treated group. These findings suggest that early degradative and angiogenic activities of medium-Az-CH-LA may be beneficial for granulation tissue formation in deep dermal burn wounds.