ABSTRACT. Collagen synthesis was evaluated by measuring prolyl hydroxylase (PHL) activity induced within rat granulation tissue by a polyester non-woven fabric (NWF, 1 × 1 cm, 0.6 mm in thickness) impregnated with a chitin or chitosan suspension ranging in concentration from 0.1 to 10 mg/ml. In addition, PHL activity induced in rat granulation tissue by a NWF impregnated with a phosphate buffer solution was examined as a control. The PHL activity in each group remained low until 4 days post-implantation (Day 4). However, in the 10 mg chitin group, the PHL activity increased rapidly without scatter of the data at Day 7 and remained at a plateau until Day 14. In other groups, PHL activity increased linearly until Day 14. The data varied widely at Day 7. Compared to chitosan, chitin at the higher concentration was found to induce stable collagen synthesis in the early wound healing process. KEY WORDS: chitin, chitosan, prolyl hydroxylase.J. Vet. Med. Sci. 66(12): 1595-1598, 2004 Chitin and chitosan have been widely studied in both engineering and medicine. In the field of medicine, the effects of chitin and chitosan on wound healing have been the focus of great attention since Prudden et al. published a paper in 1970 stating that these agents accelerate wound healing [15]. Numerous reports describe the stimulatory effects of chitin and chitosan on tissue reactions involved in wound healing [1,[3][4][5][7][8][9][10][11][12][13]. Their most notable property is their propensity to induce abundant granulation tissue formation with angiogenesis. Previous reports indicated that chitin and chitosan induced fine collagen fibers histologically [3,11]. Moreover, chitin was found to enhance synthesis of types I, III, and IV collagen [4]. However, these reports indicate only the properties of the collagen synthesized. To understand more about wound healing acceleration by chitin and chitosan, it is important to clarify the quantity of collagen synthesized as well as its properties. In this paper, we evaluated the degree to which chitin and chitosan stimulate collagen synthesis by measuring prolyl hydroxylase activity, an activity necessary for collagen synthesis in rats [18].Thirty Wistar rats (adult females, weighing 270-300 g) were used in this study. The animals were purchased from Hamaguti Laboratory Co., Ltd. (Kobe, Japan). Chitin and chitosan were supplied by Sunfive Co., Ltd. (Tottori, Japan). Molecular weights and rates of deacetylation were determined using the viscoanetric method [19] and infra-red spectroscopic method [17], respectively. The data obtained for chitin and chitosan yielded molecular weights of 300 and 80 kD, and deacetylation rates of <10 and >80%, respectively. Chitin and chitosan having a mean particle size of 3.5 µm were sterilized separately using ethylene oxide gas and suspended in phosphate buffered solution (PBS, pH 7.2) at a concentration of 10 mg/ml. According to our measurements in a previous investigation [5], the optimum doses of chitin and chitosan in granulation tissue formation in rats w...
