The Construction And Resurch Of A New Pelvic Tissue Engineering Scaffold For POP

The femal pelvic organ prolapse （POP） is a common disease, with an incidence of 40% in china and increased year by years. The POP has been regarded as a considerable gynecologic problem that seriesly influenced the the health of middle-aged and old women.It has been generally accepeted that various kinds of operation based on scaffolds were the best treatment method for POP, and the propolene scaffold widely used in clinic has the feature of certain curative effect with long-lasting period. However these prostheses carry an inherent risk of sepsis formation, erosion related to their biomechanical properties and low biocompatibility. Reversely, the bio-patch processed by decellular procedure treatment was a ideal scaffold for POP without these defects abovely mentioned.The ECM scaffold planted in body will degredated eventually. Meanwhile, the ECM could promote the proliferation of the collagen tissue and the migration of surrounding tissue, so the substitution tissues formed at the pelvic floor. Contrast to the propolene material, the ECM material show obvious predominances such as low tissue erosion, low incidence rate of algopareunia, chronic pelvic pain, and dysurination with good compliance. So the ECM material would become the perspective pelvic scaffold in the future.The ideal ECM scaffold should have these properties: good biocompatibility, self degradation with a controllable rate; no antigene effect; could induce tissue regeneration; with cellule and and mechanical strength, etc. some kinds of commonly used ECM patial or fully possesed these properties as mentioned abovely. Such as small intestinal submucosa（SIS）, urinary bladder matrix（UBM）, acellular dermis matrix（ADM）, acellular pericardium（AP）, cholecyst-derived extracellular matrix（CEM）, etc. it’s important to choose a suitable ECM scaffold for POP treatment as pelvic requirements. Unfortunely, the surgens choose the ECM scaffold for POP operation as their pleasure because lacking of a comparative study of these ECM materials for pelvic patch recently. One purpose of our study was to choose one kind of commonly used ECM materials for POP treatment base on the special enviroments and requirements of pelvic reconstruction surgery. The ECM scaffold have not been generalized in clinic for the main problem: the contradiction existed that the ability inducing surrounding tissue regeneration with the degradation period, and no sounded method presently to control this contradiction, therefore the curative effect especially the long-term curative effect are not stable. There are two meanses to tackle this problem: first, by means of tissue engineering method, the multiple-differentiation potent stem cells could be planted on the scaffold as seed cells. Then the stem cells could proliferated and differentiated when the tissue engineering scaffold was planted in vivo, and the pelvic tissue and cells could profusioned with a improved long-term curative effect theoretically. The other method is construction of the compound ECM-Propolene scaffold. With the expectation of overcoming the difects of the two kinds of materials, promoting the long-term curative rate and depressing the complications caused by single propolene material.This research prepared 5 kinds of porcine ECM materials that commonly studied at present. Designed multiple detection index based on the special environment of pelvic floor, and choose one kind of ECM as the research object best for POP scaffold. The bone marrow stem cells（BMSCs） were taken as seed cells and seeded on the chosen ECM to construct the tissue engineering scaffold for POP. At the mean time, the compound scaffold sandwished by 2 layer of chosen ECM and one layer of propolene were constructed. Then these scaffolds were planted in the vaginal submucosa of SD rats, and the tissue compliance and immune index changes were decteted. Expect to provid a new idea for the development pelvic scaffold for treatment of POP. The main experiment methods and results were exploied as followed:1, the preparation of each ECM and the choice of seeding cells1), The pericardium, demis, small intestine, urinary bladder, and cholecyst of bama’s pig were decellularized by mechnical and chemical methods, then these materials were disinfected and rinsed, and terminally sterilized using CO60γradiation2), The BMSCs of rats as the seeding cells of POP tissue engineering scaffold were detached, cultivated and indentificated successfully.2, the characteristic evaluation of each ECM in vitro and the choice of the scaffold for POP1), Each ECM materials were evaluated in terms of histological structure, water absorption ability, biodegradation ability, mechanical properties, antimicrobial activity and biocompatibility in vitro, and these ECM materials after cross-linked were evaluated also.2), The UBM was indentificated that it possessed the most long-lasting degredation period, the best antimaicrobial activity, water absorption, mechanical properties, and biocompatibility. The UBM maybe the material most to fit the pelvic environment and the best choice for POP tissue patch or tissue engineering scaffold.3, The construction of tissue scaffold and the biometical function and biocompatibility evaluation in vivo1), The experiment tat were classified to 5 group, with 12 rats each, the UBM single, UBM+BMSCs（tissue-engineering scaffold）, compound scaffold, or propelene single were planted into the vaginal submucosa of rats of each group respectively, the last group was false-surgery group. The scaffold and the tissue surrounded were harvested for HE staining and immunohistochemisry at the 1^st, 2^nd,3^rd, and the forth week after operation.2) Represented by HE staining, the inflame reaction were obvious at the first week after operation in UBM, UBM+BMSCs and compound scaffold group, but obviously relieved at the second week; the intensed inflame reaction viewed through the total experiment period in propolene group.The sequence of the imflame reaction degree was: UBM+BMSCs group<UBM group<compound scaffold group<propolene group.3) The expressing level of CD4 was: UBM+BMSCs group<UBM group<compound scaffold group<propolene group; and that of CD8: UBM+BMSCs group=UBM group<compound scaffold group<propolene group; CCR4: propolene group < compound scaffold group < UBM group < UBM+BMSCs group; CXCR3: UBM+BMSCs group<UBM group<compound scaffold group<propolene group. It was confirmed that the T cell were differentiated to Th2 cell by UBM, then led to the transplantation adaptation of the host. Reversly, the propolene induced the T cell differentiated into Th1 cells, followed by immune rejection reaction developed later.On the whole, the study evaluated several ECM materials in vitro based on the special pelvic environment, founded that UBM is the best ECM material for POP scaffold, and the biocompatibility test of UBM were carried out later. The result was that UBM and UBM+BMSCs can led to decreased inflame reaction by induce immune reaction change to immune adaptation. Even more, the UBM can modify the propolene scaffold by modulate the immune reaction and isolate inflame reaction. The degredation period of BMSCs+UBM and UBM were relatively fast, it’s inferred that the compound scaffold composed of UBM and propolene maybe the future candidate for POP patch.