| Objective: The postoperative tendon adhesion has long been a problem in hand surgery. As we know, the tendons and the surrounding tissues both participate in restoration of injured tendons, namely endogenous and exogenous healing, and the exogenous healing processes have close relationship with scar adhesion. Several serious adhesions even need twice operation to solute the tendons and their surrounding tissues. Domestic and foreign scholars have done a massive of clinical and experimental researches, attempting to prevent or ease tendon adhesion, but as yet have not achieved ideal results.Chitosan is a promising medical biomaterial in medical fields due to its marvelous special character. As the only kind of nature polysaccharide with cation, chitosan and its derivatives have successfully attracted more and more attentions. Many researchers have made it the main material of artifical tissues for its perfect biocompatibility and controllable biodegradation.The purpose of this experiment is to prepare a novel and compound membrane based on chitosan and its derivatives, and then to observe its effect on preventing postoperative tendon adhesion.Methods: 1. Prepare and purify several samples of chitosan and its derivatives. Evalute the properties of the samples and choose the most suitable materials for preparing compound membrane. 2. Carboxymethyl chitosan(CM)/ N-A-chitosan(C)/ hydroxypropylated chitosan(HP) compound membrane is prepared according to determined proportion of N-A-chiotsan, CM-chitosan and HP-chitosan. The compound film is prepared by solution casting method with double dehydrated glycerylether linked. By use of SEM, IR, cell culture, animal implantation, its cytocompatibility, cell attachment, biodegradability, biocompatibility and other properties were evaluated. 3. Models of repaired flexor tendon of chickens are used to investigate the effect of CM-C-HP membrane on preventing tendon adhesion after operation. All chickens are randomly divided into 4 groups: experimental group, the CM-C-HP membrane treated group; positive control group, the polylactic acid membrane treated group; negtive control group, no membrane treated group; normal control group: no operation group. The macroscopic and histological observation, electron microscopic observation, biomechanical tests and type-B ultrasonic tests are carried out. 4. L929 fibroblasts are cultured by blend solution of CM-chitosan and Hp-chitosan. The effect of the blend solution on L929 fibroblasts is evaluated by use of MTT, TEM, GE and so on. The mechanism of CM-C-HP membrane preventing tendon adhesion is investigated initially.Results: 1. Chitosan and its derivatives prepared and purified are aseptic and consistent with the standared of medical use. Allow for their good properties, N-A-chitosan, CM-chitosan and HP-chitosan are chose as the raw materials of the compound membrane. 2. Results show that compound film had little water content and small solution rate, having no intradermal irritation and acute toxicity. Compared with chitosan film, the compound film has better biodegradability and biocompatibility, and it can be sutured easily in operation. The growth of fibroblasts can be inhibited by the compound membrane obviously. 3. The tendons of experimental group acquire little cicatrisation and have better biomechanical properties than the tendons of negative control group. The adhesion grading result indicates a significant difference between the experimental and negative control tendons. Pathology observation indicates that the tendons treated with CM-C-HP membrane suffered a slighter inflammatory response compared to the tendons of negative control group. And moreover the fibers in the experimental group are well organized while a disorder of fibers arranged in negative control group. On the whole, the CM-C-HP compound membrane shows good effect on preventing tendon adhesion in animal experiment. 4. The growth of L929 fibroblasts is inhibited obviously after cultured by blend solution of CM-chitosan and Hp-chitosan. Along with the concentration of the blend solution gets higher, the inhibitory effect becomes more evident. The cell cycle of L929 fibroblasts has been discontinued and the fibroblasts are blocked in G0-G1 period. The result hints that CM-C-HP compound membrane produces its preventing adhesion effect through inhibiting the growth of fibroblasts.Conclusions: In this experiment, a novel CM-C-HP compound membrane with good flexibility and mechanical strength has been prepared. Animal experiment shows its good biocompatibility, biodegradability and distinguished effect of preventing tendon adhesion. With the development and application of biomaterials, this compound membrane can be exploited and utilized extensively in the future.
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