Objective Native extracellular matrix (ECM) is comprised of a complex network of structural and regulatory proteins that are arrayed into a tissue-specific, biomechanically optimal, fibrous matrix. The multifunctional nature of the native ECM will need to be considered in the design and fabrication of tissue engineering scaffolds. To investigate the extraction techniques of naturally derived nerve ECM and the feasibil ity of nerve tissue engineering scaffold. Methods Ten fresh canine sciatic nerves were harvested; nerve ECM material was prepared by hypotonic freeze-thawing, mechanicalgrinding, and differential centrifugation. The ECM was observed by scanning electron microscope. Immunofluorescencestaining was performed to detect specific ECM proteins including collagen type I, laminin, and fibronectin. Total collagen and glycosaminoglycan (GAG) contents were assessed using biochemical assays. The degree of decellularization was evaluated with staining for nuclei using Hoechst33258. The dorsal root gangl ion and Schwann cells of rats were respectively seeded onto nerve tissue-specific ECM films. The biocompatibil ity was observed by specific antibodies for cell markers. Results Scanning electron microscope analysis revealed that nerve-derived ECM consisted of a nanofibrous structure, which diameter was 30-130 nm. Immunofluorescence staining confirmed that the nerve-derived ECM was made up of collagen type I, laminin, and fibronectin. The histological staining showed that the staining results of sirius red, Safranin O, and toluidine blue were positive. Hoechst33258 staining showed no DNA within the decellularized ECM. Those ECM films had good biocompatibil ity for dorsal root gangl ion and Schwann cells. The cotents of total collagen and GAG in the nerve-derived ECM were (114.88 ± 13.33) μg/ mg and (17.52 ± 2.34) μg/mg, showing significant difference in the content of total collagen (P lt; 0.01) and no significant difference in the content of GAG (P gt; 0.05) when compared with the contents of normal nerve tissue [(54.07 ± 5.06) μg/mg and (25.25 ± 1.56) μg/mg)]. The results of immunofluorescence staining were positive for neurofilament 200 after 7 days and for S100 after 2 days. Conclusion Nerve-derived ECM is rich in collagen type I, laminin, and fibronectin and has good biocompatibil ity, so it can be used as a nerve tissue engineering scaffold.
Objective To detect the variation rule of different cellular components, extracellular matrix, matrix-metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases（TIMPs）in proliferative membranes in proliferative vitreoretinopathy (PVR) with different courses of disease, and to investigate the remodeling mechanism of PVR. Methods Sixteen surgically excised specimens of proliferative membranes from patients with rhegmatogenous retinal detachment combined with PVR with the course of disease of 2 months to 8 years were selected. The different cellular component of retinal pigment epithelial (RPE) cells and glial cells, component of extracellular matrix including fibronectin, laminin，and collagen types Ⅰ to Ⅳ, and matrix metalloproteinases (MMP2, MMP9) and TIMP1 in proliferative membrane were labeled by immunohistochemical method. The variati on of those labeled components in proliferative membrane in PVR duration and the correlation between these components and the course of PVR were analyzed. Results As the duration of PVR increased,the expression of RPE cells, fibronectin and MMP2 decreased (Plt;0.05）,while glial cells,collagen type Ⅰ and Ⅲ increased (Plt;0.05）.The positive staining of laminin and collagen type Ⅱ and Ⅳ were found, but the association with PVR duration was not detected. A negative correlation between PVR duration and RPE cells, MMP2, and fibronectin respectively and a positive correlation between PVR duration and glial cells, collagen Ⅰand Ⅲ respectively were detected. MMP2 positively related with variation of fibronect in. Positive staining of MMP9 and TIMP1 was recorded but did not change with the variation of the disease course. Conclusion During the formation and development of proliferative membrane in PVR, RPE cells, glial cells, fibronectin, collagen type Ⅰand Ⅲ and MMP2 take part in the remodeling of proliferative membrane. (Chin J Ocul Fungdus Dis, 2006, 22:308-312)