Effect of electrochemically dealloying Ti6Al4V abutments on human gingival fibroblasts / 口腔疾病防治

Objective@#To investigate the effects of electrochemically dealloying of Ti6Al4V abutments on human gingival fibroblasts (HGFs) and to provide experimental evidence for surface modification of implant abutments.@*Methods@#The samples were divided into an NC group (negative control, no other treatment on a smooth surface), an NM-1 group (nanomesh-1, electrochemical dealloying treatment in 1 mol/L NaOH 1 h on 2 V voltage), and an NM-2 group (nanomesh-2, electrochemical dealloying treatment in 5 mol/L NaOH 1 h on 2 V voltage). The surface morphologies of the samples and the adhesion of HGFs on the sample surfaces were observed with scanning electron microscopy (SEM). The surface hydrophilicities of the samples were measured with a contact angle measuring instrument. The proliferation of HGFs on the different samples were evaluated with CCK-8, and the expression of adhesion-related genes, including collagen Ⅰ (COL1A1), collagen Ⅲ (COL3A1), fibronectin 1 (FN1), focal adhesion kinase (FAK), vinculin (VCL), integrin α2 (ITGA2), and integrin β1 (ITGB1), on the different samples was measured with qRT-PCR. The expression of vinculin on the surfaces of HGFs was observed via confocal laser scanning microscopy (CLSM) after immunofluorescent staining. Collagen fiber secretion and syntheses of HGFs from different samples were evaluated via Sirius red staining.@*Results@#SEM revealed the formation of ordered and uniform three-dimensional mesh structures on the surfaces of the NM-1 and NM-2 groups, with grid diameters of approximately 30 nm for the NM-1 group and approximately 150 nm for the NM-2 group. Compared with that of the NC group, the water contact angles of the NM-1 group and NM-2 groups were significantly lower (P<0.000 1). Cell proliferation in the NM-1 group was significantly greater than that in the NC group (P<0.01). Moreover, there was no significant difference in the water contact angles or cell proliferation between the NM-1 group and the NM-2 group. SEM revealed that HGFs were adhered well to the surfaces of all samples, while the HGFs in the NM-1 and NM-2 groups showed more extended areas, longer morphologies, and more developed pseudopodia than did those in the NC group after 24 h. qRT-PCR revealed that the expression levels of the adhesion-related genes COL1A1, COL3A1, FN1, FAK and VCL in the NM-1 group were significantly greater than those in the NC and NM-2 groups (P<0.01). The expression of vinculin protein in the NM-1 group was the highest, and the number of focal adhesions was greatest in the NM-1 group (P<0.01). The results of Sirius red staining showed that the NM-1 group had the highest secretion and syntheses of collagen fibers (P<0.000 1).@*Conclusion@#The three-dimensional nanomechanical structure of Ti6Al4V modified by electrochemical dealloying promoted the adhesion, proliferation, collagen fiber secretion and syntheses of HGFs, and electrochemical dealloying of Ti6Al4V with a grid diameter of approximately 30 nm obviously promoted HGF formation.

Morphology and Adhesion Complex of Cultured Epithelium, on Amniotic Membrane in Vitro and in Vivo

PURPOSE: The morphologic characteristics and adhesion complex formation of cultured limbal epithelium of rabbit on amniotic membrane, in vitro and in vivo. METHODS: Rabbit limbal explants were cultured in vitro on amniotic membrane for 4 weeks. In the in vivo culture, the rabbit corneal epithelium was removed. Next, a tunnel was created at the limbus and, the edge of amniotic membrane was secured in the tunnel and cultured for 4 weeks. The proliferation of epithelium on the amniotic membrane was observed for 4 weeks at 1 week intervals. RESULTS: AE-5 immunohistochemical staining was positive and PAS staining was negative for cultured rabbit limbal epithelium, in vitro and in vivo. Hematoxylin and Eosin staining showed the morphologic characteristics of normal rabbit corneal epithelium in both groups. Transmission electron microscopy performed at an interval of 1 week showed adhesion complex by 3 weeks of in vitro culture, and no significant change was seen until week 4. The formation of the adhesion complex was shown starting at week 1 of in vivo culture and increased until week 4. CONCLUSIONS: The morphology of corneal limbal epithelium of rabbits cultured on amniotic membrane in vitro and in vivo, did not differ significantly compared with normal rabbit epithelium. In vivo culture resulted in more a normal-looking adhesion complex compared with the in vitro culture.

Ultrastructural Changes of Corneal Epithelium and Basement Membrane in Neurotrophic Corneal Ulcer

PURPOSE: Neurotrophic keratitis is corneal epithelial defects and stromal thinning associated with loss of sensory function in the ophthalmic branch of the trigeminal nerve. The purpose of this study was to determine the ultrastructural changes of corneal epithelium and basement membrane in neurotrophic keratitis. METHODS: The corneal tissues were obtained from the elevated margin of corneal ulcer in 5 patients with neurotrophic keratitis. Electron microscopic studies were performed. RESULTS: Degenerated epithelial cells, widened intercellular spaces and infiltrated inflammatory cells were observed. In addition, discontinuous basement membrane and loss of adhesion complex including hemidesmosome, anchoring fibril and anchoring plaque were found. CONCLUSIONS: These results suggest that ultrastructural pathology of persistent epithelial defect and inadequate healing of neurotrophic keratitis are loss of adheson complex, discontinuous basement membrane, degenerated epithelial cells, and infiltrating inflammatory cells.

Electron microscopic studies of epithelial adhesion complex of keratoconus

PURPOSE: Keratoconus is a bilateral noninflammatory ecstatic disease of cornea. Clinical manifestations and treatments are well-described , but the exact pathophysiology has many debates. There are many reports on pathologic abnormalities of keratoconus, but few reports on epithelial adhesion complex. The authors investigated the abnormalities in epithelial adhesion complex of keratoconus. METHODS: Using 4 corneas from 4 recipients of penetrating keratoplasty, examination was done with transmission electron microscope (Hitachi-600, Japan) after proper fixation and staining. Central and peripheral portion of each corneal tissues were examined. RESULTS: In two tissues, severe degeneration of basement membrane and Bowman's layer were found. Some degree of abnormalities was found in other tissues, which had minimal change. Some of hemidesmosomes, the most distinct part of adhesion complex, were found only in well-maintained tissue but the distribution was abnormal. CONCLUSIONS: The fact that basal plasma membrane had selectively more degenerations and changes than intercellular plasma membrane implies pathophysiology of keratoconus on adhesion complex, basal plasma membrane, basement membrane and Bowman's layer. Further study on this issue will reveal more information as to its pathophysiology.

Immunogold Localization of Type VII Collagen in the Adhesion Complex of Pathologic Cornea

Type VII collagen is one of the major structural components of the corneal epithelial adhesion complex. Using the immunogold technique combined with indirect immunofluorescence analysis, the fine structural distribution of type VII collagen was studied in the corneas obtained from 5 enucleated hyman eyes (age range, 1-77 years) including one pathologic cornea from graft rejection. The findings on normal cornea corroborated the results from previous studies. In pathologic cornea from graft rejection, type VII collagen antibodies generated linear and irregular patchy fluorescence staining along the epithelial-stromal interface and immunogold binding to type VII collagen mainly occurred within the undulating lamina densa, more densealy distributed anchoring plaques and anchoring fibrils. The distribution of type VII collagen in pathologic human cornea from graft rejection is similar to normal human cornea. But, in pathologic cornea, type VII collagen is more densely distributed in superficial stroma and forms more extended anchoring network, which may be derived from the increased secretion of the type VII collagen due to the activated basal epithelial cell during healing process.