ABSTRACT
BACKGROUND: It has been reported that chitosan can inhibit scar formation and promote wound healing. Medical invisible antimicrobial film is a new type of membrane materials which comprises chitosan as ground substance.OBJECTIVE: To determine the inhibitory effects of medical invisible antimicrobial film on the operative incision scar, and to observe its effects on wound healing.DESIGN, TIME AND SETTING: A controlled animal study was conducted at the IVC Experimental Animal Room, West China School of Pharmacy, Sichuan University from August to October 2007.MATERIALS: Medical invisible antimicrobial film stock solution was colorless transparent sticking solution, which formed colorless transparent film following spray painting (specification: 40 mL), provided by Chengdu Chaojl Technology Co., Ltd. (lot number 070501).METHODS: A total of 16 healthy Sprague Dawley rats aged 20 to 23 days were selected. Full linear skin incisions were operated in aseptic condition. After operation, the experimental group (right side) was sprayed medical invisible antimicrobial film 0.5 mL/time, once a day, for totally 3 days. The control group (left side) received an equal volume of 0.9% sodium chloride injection, with natural cure.MAIN OUTCOME MEASURES: At 3, 7 and 14 days following surgery, incision skin specimens were obtained, and subjected to hematoxylin-eosin staining and Masson staining was applied to observe wound healing and the formation of scar, then the scar area was analyzed.RESULTS: The scar relative mean area of control group was 154 069±51 356 and the experimental group was 98 200±34 719 on the postoperative 14~(th) day. The two groups were significantly different (P < 0.05). At 14 days following surgery, optical microscope showed that the experiment group had less collagen fibers and fibroblast accumulation. At 3 days, compared with the control group, the experimental group had less epithelization period, more granulation tissue and less inflammatory cell infiltration.CONCLUSION: The medical invisible antimicrobial film has inhibitory effect of the formation of operative incision scar, and no influence on wound healing of operative incision.
ABSTRACT
BACKGROUND: RT-Q medical biomembrane, the novel copolymer synthesized from lactic acid and hyaluronic acid, not only possesses the advantages of hyaluronic acid, such as multiple biological functions, excellent flexibility and biocompatibility, but also has the merits of polylactic acid fragments to be easily processed and transformed to membrane when encountering water. OBJECTIVE: To investigate the hemostatic effect of RT-Q medical biomembrane in rat external jugular vein hemorrhage model, and to evaluate its histocompatibility by locally applying it to rat muscle. DESIGN: Randomized controlled animal trial.SETTING: Department of Pharmacology, Department of Pharmacognosy, West China School of Pharmacy, Sichuan University.MATERIALS: 130 male Wistar rats aged 6 weeks, weighing 170-210 g, were selected. Eighty rats were used for evaluation of hemostatic effect, and the other fifty were used in biocompatibility experiment. Animal intervention met the animal ethical standard. RT-Q aerosol composed of DL-lactic acid and hyaluronic acid, α-cyanoacrylate, acetone (solvent), freon (propellant) and excipient aerosol composed of acetone and freon (propellant) (Batch number 20050311) were provided by Department of Pharmaceutics, West China School of Pharmacy, Sichuan University.α-cyanoacrylate medical adhesive(SUNCON medical adhesive) (Batch number 20050930) was produced by Beijing Suncon Medical Adhesive Science and Technology Development Co., Ltd. METHODS: Haemostatic effect: Eighty male rats were randomly divided into four groups, served as RT-Q, SUNCON (positive control), excipient group and non-treatment group (negative control), twenty in each group. After anesthesia was induced, external jugular vein of rats was exposed, and an approximately 0.6 cm incision was made to create hemorrhage. The bleeding areas were blotted by antiseptic gauze. After removing the gauze, the bleeding surfaces were immediately treated with RT-Q aerosol in the RT-Q group, excipient aerosol in the excipient group, 0.15 mL SUNCON medical adhesive in the SUNCON group, or no agent in non-treatment group, respectively. Then, injury surfaces were covered by gauze. In the non-treatment group, bleeding was left to naturally stop. Bleeding time and blood loss (gauze weight after hemostasia - that before hemostasia) were determined. Local histocompatibility: Rats were divided into A and B groups. Incision was made in rat post-leg muscle after anesthesia was induced. Left bleeding surfaces were treated with excipient aerosol, and right bleeding surfaces were treated with RT-Q aerosol in group A (n=30). The same incision as the group A was made, but no intervention was performed in the group B (n=20). Tissues were possessed and HE-stained for pathological observation under light microscope at days 1, 2, 3, 4, 5, 6, 7, 15, 23, 30 after the surgery. Effect of biomembrane on wound healing, degradation and toxicity to tissues surrounding injuries were observed. MAIN OUTCOME MEASURES: Bleeding time and blood loss in hemostatic experiment; wound healing, biodegradation and toxicity to tissues surrounding injuries in local histocompatibility experiment. RESULTS: 130 rats were involved in the result analysis. Histopathologic examination showed RT-Q membrane had no effect of promoting or delaying wound healing. Membrane formed by RT-Q aerosol began to degrade on the 15th day, absorbed completely during 3-4 weeks, and had no toxicity to surrounding tissues. Bleeding time and blood loss were reduced in the RT-Q group than in the non-treatment group and the excipient group (P < 0.01). There was no significant difference between the RT-Q group and the SUNCON group (P > 0.05).CONCLUSION: RT-Q medical biomembrane as α-cyanoacrylate medical adhesive has significant hemostatic effects on topical bleeding, and possesses good histocompatibility.