Establishment And Application Of Experimental Animal Model For Hypertrophic Scar

Objective: To establish animal model of rabbit ear for hypertrophic scar and to observe the effect of B.Pathogenesis of surgical infection on the formation of hypertrophic scar in rabbits ears after injury. Methods: Full-thickness excisional wounds ,1cm in diameter,were created over the ventral surface of 6 adult New Zealand white rabbits ears and then excisional wounds healed ,which was called animal model of rabbit ear for hypertrophic scar. Wound healing models were established on 20 adult rabbit ears, according to methods mentioned above,which were randomly divided into control group(group A) Staphylococcus aureus group(group B) E.coli group(group C)P.aeruginosa group(group D)and were observed wound healing time of groupA,B,C and D incidence of forms of excessive scar.The change of fibroblasts in forms of excessive scar were investatigated in different time thorough histomorphometric. TGF- β1 and collagen- I in forms of excessive scar were tested in different time through immunohistochemistry. Result: Excessive dermal scars with some clinical and histologic on rabbits ears are similar to human hypertrophic scar and incidence of excessive dermal scar is 66.7%.Histologyically,these scars demonstrated largely fibroblasts proliferation in early stage scar and had irregularly arranged collagen fibers,often with a circular or whorled appearance in middle stage scar ,which is called animal model for human hypertrophic scar. The mean values of wound healing time of groupA,B,Cand D was 13.367 ± 1.025, 19.283 ± 1.091, 13.967 ± 0.948, 16.233 ± 0.981 days respectively, which have statistical differecnce. Incidence of excessive dermal scar ofgroup A,B,Cand Dwere 67.7%,90%,75%,80%.Both group B and group A were found to have statistical differecnce. The mean values of wound healing time of groupA,B,C and D are positively relative with incidence of forms of excessive scar.The number of fibroblast and the express of TGF- β1 and collagen- I in three groups are higher than that in the control group. The number of fibroblast , the express of TGF-β1 and the express of collagen- I in every group are the highest in the early stage. The number of fibroblast and the express of TGF- β1 and collagen- I in all groups decrease along with the time course. The express of TGF- β1 is positively relative with the express of collagen- I .Conclusion: the animal model of rabbit ear for hypertrophic scar is simple,stable and repeated experiment method for formationing mechanism and preventive study of human hypertrophic scar. B.Pathogenesis of surgical infection enlarge healing time and increase forms of excessive scar incidence in rabbits ears,which may be considered a important promoting factor in formation of hypertrophic scar. The number of fibroblast ,the express of TGF-β1 and collagen- I in healed excisional wounds of rabbits ears are higher than normal tissues,like human hypertrophic scar ,which is made the important basis for formationing mechanism of human hypertrophic scar. The basis which helps us prevent human hypertrophic scar in cell and molecule biology and provide effective experimental ways for study of human hypertrophic scar.