Incised wounds were made in rabbits, and some of the wounds were dressed with chitosan, and others with gauze. After bleeding stopped, hemoglobin in dressings was measured to determine the hemostaic effect. Wounds were redressed, and healing process was studied histologically. The results showed that less Hb was detected in chitosandressing than in gauze. On day 9 after wounding, the content of granulation tissue and collagen formation in the chitosan dressed wounds was more than that in Vaseline gauze dressed group. It suggests that chitosan dressing is effective in hemostasis for incised wounds and may be helpful in wound healing process.

Objective:To study the expression of P53, Bax, Bcl-2 proteins and the role of cell apoptosis in the formation and development of acute radiation-induced skin ulcers.Methods:A rat model which was locally irradiated with 60 Co γ-rays was used, and the pathological changes were observed for 40 days. Immunohistochemistry and TUNEL assay were performed which enabled the detection of P53, Bax, Bcl-2 and cell apoptosis during the formation and development of radiation skin ulcers.Results: Skin ulcers were found on day 14 after irradiation, and enlarged and deepened gradually during the observation period. P53 was over expressed during days 11 to 40 after irradiation and was localized in vascular endotheliocytes and smooth muscle cells. Bax was moderately positive during days 14 to 21 and weakly positive during days 28 to 35, and was localized in vascular endotheliocytes, some fibroblasts and proliferating keratinocytes. Bcl-2 was weakly positive during days 1 to 11 after irradiation, and was located in keratinocytes, hair follicular cells and some vascular endotheliocytes. Bcl-2 was negative during days 11 to 40.The rate of cell apoptosis, especially of vascular endotheliocytes,wash igher than that in the early process of normal wound healing. Conclusions:After irradiation,the increased expression of the apoptosis-inducing protein P53, Bax and the decreased expression of the apoptosis-inhibiting protein Bcl-2 might be associated with the high rate of apoptotic events, and play important roles in the formation and development of radiation skin ulcers.