Experiment Study Of Acetobacter Xylinum Cellulose Dressing

BackgroundThe healing of wound surface is a complicated courses.Fibroblast (Fbs),cytokine and procollagen (PC) and some part of cell growth factor are the key point among the wound surface reparation cource.Fbs participate the healing whole course after cutaneous deficiency,then the most important biology changes are the strengthen of Fbs's reproduct-ive activity and increace of collagen protein synthetic and the content changes of cytoki-ne.Wound surface can be accelerate healing through improve Fbs's bionomics. Both the organism's metabolism features and milieu exterieur of wound surface have great significance to healing.Sterility of wound surface and moisten of surroundings are all the key point for wound healing.According to the clinical investigation,wound surface need wrapped by dressing and will not be exposed in the surroundings directly. So the healing of wound surface is influenced by surroundings of dressing. Now,people found dressing which synthesized by Bacterial Cellulose (BC) overcome the upper defects and also have some good features,including high water ratio,high hydrophilism,high tensile strength and high biocompatibility,which can refrain the growth of wound surface bacterium and promote wound surface healing et al.The using of BC will have widespread application perspective in medicine and biomedical engineering territory,and the study of BC is a hot spot biomaterial investigation nowadays.Meanwhile BC will have great development as a neotype biosynthesis dressing in medical world.Axcd's main composition is Bacterial Cellulose by produced Acetobacter xylinum (Ax) which contain in Acetobacter aceti (Aa).Its construction identical to plant cellulose which belong to native cellulose.Axcd have outshine others in many dressings because of its distinctive merits.Axcd is the main study object in this study,and its main study content include two part.The first study include pro-tow part (study of animal experiment) during master period.The influence of Fbs and PC and some cell growth factor are the mose emphasis study.In order to approach the mechanism of promote healing by Axcd.Objective1. To understand Axcd's therapeutic efficacy and safety of operation wound surface(depth reach deep layer of dermis), including study its mechanism action of refrain bacterium from infected wound surface and ability of hasten wound surface healing.2.To approch human skin fibroblast's (HSFb) proliferation and synthetical ability of collogen and the excete content changes of transforming growth factor-β1 (TGF-β1) and interferon gamma (IFN-γ) and basic fibroblast growth factor (bFGF) by Axcd,that may be related with promote wound surface healing.Contents and methods1.9 small pigs were divided into 3 groups random completely,each groups have 3 pigs,and 6 models of animal infection wound surface were made on every pigs,every wound surface were inoculated combining bacterium including Staphylococcus aureus (SA)and Escherichia coli(EC).Experimental group,control group 1 and 2 include Axcd ,antibiosis gauze which contain neomycin-berberine solution and petrolatum gauze respectively.To observe their security and therapeutic effect of hasten wound surface and ability of control wound infection. 2. Fibroblasts were obtained from the digested and aparted method of primary culture and identified by morphology and immunohistochemistry.The sixth purified fibroblasts were divided into two groups at random and cultured with Axcd and sham respectively. MTT methods was used to measure OD number of each hold after being cultured for 24,48,72h respectively. Cell cycle was measured by flow cytometry.The hydroxyproline in the cultural medium was determined by alkaline hydrolysis.The amount of typeⅠandⅢprocollagen(PCⅠ,PCⅢ)in the supernatants and the PCⅠto PCⅢratio were determined. The excrete content of TGF-β1 and IFN-γand bFGF in cultured human fibroblasts was detected by relative ELISA kits.Results1.After made animal infection wound surface models,determine the bacterial count every other 4 days after the first day of operation,the consequences indicate that total bacterium inhibition ratio after the 5d,9d,13d and 17d respectively.The effect of Axcd's total bacterium inhibition ratio is better compare with other two groups.The healing time of wound surface which use Axcd is ahead of other two groups about 3-5d by obersavation of ordinary and pathological section.Axcd have not influence to animal blood chemical examination,liver and renal function,local sensitization and general symptom.2. Fibroblasts was cultured with Axcd,compared with blank groups,OD numbers were obviously different (P<0.05). Employing the flow cytometry technique we observed the cell cycle of S+G2/M stage and the proliferation index (PI) were increased (P<0.05).Co-mpared with the other group the hydroxyproline in the cultural medium was increased (P<0.05),when the cells were stimulated by Axcd.To compare the sham group,PC I, PCIII amounts (P<0.05),and decreased ratio of PC I to PCⅢ(P<0.05).ELlSA kits: TGF-β1 content of cell cultured with sham in 24hr is 89.27±9.85 pg/ml, with Axcd is 134.75±12.40 pg/ml, and with sham in 48hr is 128.48±10.53 pg/ml, with Axcd is 188.32±15.68pg/ml. IFN-γcontent of cell cultured with sham in 24hr is 108.35±10. 24pg/ml, with Axcd is 73.56±8.73 pg/ml, and with sham in 48hr is 130.25±14.50 pg /ml, with Axcd is 85.78±13.62pg/ml. bFGF content of cell cultured with sham in 24hr is30.53±6.32 pg/ml, with Axcd is 48.35±8.87 pg/ml, and with sham in 48hr is 42.65±5.45pg/ml, with Axcd is 65.20±7.36pg/ml.ConclusionAxcd have great applicate scopes because of many features,such as slick,moisten, and can make various kinds shapes according to wound surface's position and size,and have the ability reduce invation of bacterium in wound surface.The inhibiton ration of Axcd outweigh other two groups to SA and EC.Axcd have the better bacteriostatic action and ability of promote wound surface healing compare with other dressings. Axcd can enhance the growth of HSFb and the collage synthesis and content of TGF-β1 and bFGF of cultured human fibroblasts,but the content of IFN-γis down regulation.It might be beneficial to ranulation tissue formation during wound healing.All in all,it is the ideal wound dressing in clinical at present.