| Objective (1) Prepare bacterial cellulose (BC) film and study the basic physical and chemical properties. (2) Study the biocompatibility of BC film in vitro. (3) Investigated the prevention effect of BC membrane on epidural fibrosis developing post-laminectomy in a rabbit model and in vivo biocompatibility.Methods (1) Prepare BC membrane with acetobacter xylinum. Analysis the molecular structure and morphology of BC film, measure its water content, thickness, tensile strength, elongation at break and modulus of elasticity. Immerse BC membrane in SBF for six months to observe the degradation in vitro. (2) Prepared different concentrations of the extracts of BC film, culture L929 fibroblast with the extracts. Assess cell morphology and analyze cell proliferation by MTS to evaluate the cytotoxic of BC film. (3) 40 Japanese white rabbits were randomly divided into four groups:blank control group, BC group, expanded polytetrafluoroethylene (ePTFE) group and polyurethane (PU) group. Laminectomy model was prepared and cover the laminectomy defect with above materials in each group. After 3 months,3 animals in each group were randomly selected to get magnetic resonance imaging (MRI) examination to evaluate epidural scar formation. The animals were sacrificed after 1 year and their spinal columns were totally removed for peel-off testing and histological analysis to assess the extent of adhesion formation and inflammation. Heart, liver and kidney issues were taken for histological analysis to assess toxicity. Animals in the BC group and the control group got measurements of blood to evaluate liver and kidney function before and after operation. BC films were embedded in subcutaneous issue and muscle and were taken for histological analysis to assess inflammation.Results High purity cellulose constitute a three-dimensional network structure in BC film. BC film got an average moisture content of 94.5%, a thickness of (0.80±0.07) mm, a tensile strength of (3.14±0.38) Mpa, elongation at break of 28.81% and an elastic modulus of 11 Mpa. No degeneration was observed after 6 months soaking in SBF. Morphological analysis were non-toxic in each concentrations extract, the number of cells in each group were increased with the incubation time and there were no significant difference between groups (P>0.05). Subcutaneous, intramuscular embedded BC film observed no inflammatory reaction in pathology. Both BC group and control group got short-term increasing in ALT and AST after operation, which went back to normal 7 d after surgery. BUN, Bcr testing got normal result. There were no significant difference in ALT, AST, BUN, Bcr between the two groups at each time point (P>0.05). MRI and histological analysis showed significantly less scar tissue formation in the 3 treatment groups. There was significant difference of pathological analysis score and peel-off testing grade between 3 treatment groups and blank control group (P<0.01, χ2=25.545) while no significant difference was found in the 3 treatment groups (P=0.494,χ2=1.441). Heart, liver, kidney HE staining showed no abnormalities.Conclusions The anti-adhesion membrane of BC shows satisfactory mechanical properties and biocompatibility and is effective in inhibiting epidural fibrosis and peridural adhesions. |
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