Research progress in regenerative medicine / 国际生物医学工程杂志

Damage of tissues and organs by wound,tumor resection,and congenital malformation is always the tough problems to clinician.At present,the damaged tissues and organs are usually replaced by tissue and organ transplantation or by bionic implantation in clinic.Although these methods have some advantages respectively,they have some serious drawbacks at the same times.Regenerative medicine,which depends on the findings of regenerative biology research,applies the cellular therapeutics based on cell transplantation and the principle of tissue engineering with biomaterial as scaffolds to the repair or replacement of the damaged tissues or organs.The goal of the regenerative medicine is to reconstruct the structure and restore the function of damaged tissues or organs by promoting the regenerative potential of adult stem ceils(ASC)in vivo.This paper focuses on the recent research progress in the field of regenerative biology and medicine.

Cultivation and morphological characteristics of rat adipose tissue-derived vascular endothelial cells in vitro / 生物医学工程学杂志

The subcutaneous adipose tissue from the inguen of four Sprague-Dawley rats was obtained, then digested with one volume of collagenase type I and cultured with BGJb medium. The obtained adipose stromal cells were induced in human endothelial-SFM for 7 d. The cells were observed under inverted microscope every day and identified by transmission electron microscope and immunocytochemical staining with factor VIII antigen. The results showed the induced cells uniformly had characteristic cobblestone morphology of endothelial cells. Factor VIII antigen staining was positive in cytoplasm. Under transmission electron microscope, the cells displayed many finger like microvilli and numerous lysosomes, mitochondria, a few coarse endoplasmic reticulum and Weibel-Palade bodies. The characteristics of the rat adipose tissue-derived endothelial cells were consistent with those of vascular endothelial cells derived from other tissues. It seems that subcutaneous adipose tissue may represent a new alternative source of endogenous vascular endothelial cells.

The reconstruction of bioengineer active corneal stroma and its biocompatibility study / 生物医学工程学杂志

This paper aims to explore the biocompatibility of bioengineer active corneal stroma (BACS), as the biological carrier for cornea reconstruction, to provide the basis for future study on clinic application. The cells and immunogenic components of cornea stroma were removed through different extract methods. A complex of functional corneal stroma cells and acellular corneal stroma was used to reconstruct BACS. Their morphological characteristics and ultrastructures were observed with transmission electron microscope. The complex was grafted into interlamellar stromal pockets. Cells were labeled by BrdU to examine the survival and conversion after grafting. The cells could survive and proliferate in acellular corneal stroma. All the nuclei of the corneal stromal cells showed positive labeling with BrdU in the BACS. After 4 weeks, BACS became transparent; after 8 weeks, the bioengineer active cornea stroma was fully reconstructed.

Heterotopic osteogenesis of autogenous marrow stromal cells with recombinant human bone morphogenetic protein 2 gene transfection and porous calcium phosphate ceramic as a scaffold / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the heterotopic osteogenesis of autogenous marrow stromal cells loading on porous calcium phosphate ceramic scaffolds with rhBMP2 gene transfection in a Sprague-Dawley rat model.</p><p><b>METHODS</b>Autogenous marrow stromal cells were obtained from left femurs and tibias of 20 male adult SD rats under general anesthesia and sterile condition and cultured in alpha-Minimal Essential Medium supplemented with 15% fetal bovine serum. RhBMP2 gene was transfected into stromal cells by means of LipofectAMINE 2000 reagent five days after primary culture. The stably gene expressive cells were selected with G-418 for 14 days and mixed with stromal cells without transfection. The mixture cells were seeded and subcultured for another 10 days in porous calcium phosphate bioceramic that had been subjected to surface-modification via soaking in human plasma fibronectin. The cell-ceramic compound was implanted subcutaneously and intramuscularly in the corresponding rat. Lab animals were sacrificed at two-week intervals till twenty weeks postoperatively and the involved samples were removed.</p><p><b>RESULTS</b>Morphologic and histological study demonstrated that cell-ceramic compound had an ability of heterotopic osteogenesis, which was similar to that of autogenous osteoblasts in previous study.</p><p><b>CONCLUSION</b>It seems that autogenous stromal cells with rhBMP2 transfection acts as a bioreactor promoting proliferation and differentiation of stem cells when they are replanted into the corresponding animals.</p>

Chemical synthesis of biodegradable poly-para-dioxanone and its application for mandibular fracture fixation / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe mandibular fracture healing after synthesized bioabsorable poly-para-dioxanone (PDS) ligature fixation.</p><p><b>METHODS</b>Para-dioxanone monomer was prepared by chemical reactions of metallic sodium, ethylene glycol and other raw materials. PDS was synthesized by polymerizing the purified para-dioxanone in the presence of catalyst under the conditions of negative pressure and certain temperature. PDS ligature was obtained by processing the polymer into small granules, drying and melt-extruding through a spinnerette. Eighteen adult male New Zealand rabbits were assigned randomly into two groups. After mandibular fracture models were created, reductions of the artificial fractures were accomplished by means of transosseous PDS ligatures on each of 12 rabbits in experimental group. While the other six rabbits without any internal fixation were set as control. Schedules for killing were arranged to give postoperative samples at two-week interval till 12th week.</p><p><b>RESULTS</b>Radiographical and histological examinations demonstrated that all fractures fixed with PDS ligatures healed without any complication. Periosteal and cartilaginous osteogenesis was observed in newly formed external callus. In contrast, bone fragment migration and the consequent nonunion occurred in the control group. PDS ligature degraded and absorbed without interference with osseous union and healing. The tensile strength reduction of PDS ligature was prior to its absorption in vivo.</p><p><b>CONCLUSION</b>The synthesized PDS is a colorless, flexible, themoplastic and monofilament fiber, which can be sterilized by ethylene oxide embalmment without serious loss of tensile strength. It seems that the application of this macromolecular material in internal fixation is of great worth for further study.</p>

Effects of doxycycline on the proliferation and invasion of adenoid cystic carcinoma SAcc83 cells / 实用口腔医学杂志

Objective:To study the effects of doxycycline on the proliferation and invasion of adenoid cystic carcinoma cells.Methods:MTT assay was applied to study the effects of doxycycline on proliferation of SAcc83 cells. Activity of type IV collagenase was detected by the method of gelatin incorporated SDS PAGE electrophoresis.Monolayer cell organ culture was carried out to study the invasion of the cells.Results:Doxycycline at 5～50 ?g/ml inhibited the proliferation of adenoid cystic carcinoma cell in a dose and time dependant manner. 10 ?g/ml of the drug inhibited type Ⅳ collagenase and decreased the invasion of adenoid cystic carcinoma cells by 48%.Conclusion:Doxycycline can inhibit proliferation and invasion of SAcc83 cells.