Chitosan Sponge with Photocrosslinkable Chitosan Hydrogel Stimulates Large and Impaired Wound Healing in Rats

Aim: We have previously reported that a photocrosslinkable chitosan hydrogel (Az‐CH‐LA) has induced wound healing in diabetic mice. However, deep and large skin wounds may be not enough covered by Az‐CH‐LA only. Therefore, we evaluated whether chitosan sponge with Az‐CH‐LA accelerates large and impaired wound healing. Methods: Full thickness‐square wounds (25 × 25 mm) were prepared on the upper back of twenty‐four male Sprague Dawley rats. Chitosan sponge and/or Az‐CH‐LA aqueous solution (30 mg/ml) was added onto the wound of each rat and was then irradiated with UV light. Thus, the following four experimental groups were studied: Group (G) 1: control, G2: Az‐CH‐LA solution only, G3: Chitosan sponge + 0.9% saline, or G4: Chitosan sponge + Az‐CH‐LA solution. The changes in wound area were measured at day 2, 4, 8, and 16. The skin including the wound was removed from each rat for histological examination. Results: The wound area in G4 at day 2, 4, and 8 was significantly smaller than the other groups. The number of neovessels and the thickness of granulation tissue in G4 at day 2 and 4 were significantly higher than the other groups. Conclusions: The chitosan sponge with Az‐CH‐LA has been found to be more effective in large and impaired wound healing compared with a Az‐CH‐LA solution only.