[Impact of regenerated silk protein membrane on the cytokine expression of transfected human corneal epithelium cells].

OBJECTIVE: The purpose of this research was to study the influence of the regenerated silk fibroin film (SF) on cytokines expression of transfected human corneal epithelial cells (HCECs) and to investigate the possibility of constructing biomaterial complex using SF, modified by transgenic cells. METHODS: Empirical study.Ad-VEGF(165) was injected into the limbus of a rabbit's cornea to induce cornea neovascularization (CNV). CNV was evaluated by growth areas and VEGF characteristic was evaluated by immunohistochemistry. HCECs was cultivated on silk protein membrane in the cell cultivation plate. Modality of cells, activity of cell proliferation and infection efficiency of Ad-VEGF(165) were monitored to evaluate the biocompatibility of silk fibroin. The angiogenesis-related cytokines in the cell cultivation supernatant was measured using ELISA method such as vascular endothelial growth factor (VEGF), angiogenin 1 (Ang1), epidermal growth factor (EGF) and transforming growth factor-beta (TGF-beta) in the supernatant (Two-way analysis of variance). RESULTS: (1) The area of corneal neovascularization was observed to be (7.60 +/- 1.12) mm(2) at 1 week after Ad-VEGF(165) was injected and it became (12.28 +/- 2.54) mm(2) another three weeks later. Positive expression of VEGF in corneal stromal was observed by immunohistochemistry at 3 d, 1 week and 1 month after injection. (2) There was no difference noticed in amorphous, growth curve and infection efficiency of Ad-VEGF(165) between both cells culture conditions of silk protein membrane and plate cultivation. (3) After transfection, the concentration of VEGF, Ang1, EGF and TGF-beta expressions in the corneal epithelium cell cultivation supernatant with silk protein membrane as carriers was (721.67 +/- 66.97) ng/L, (1042.67 +/- 315.81) ng/L, (2421.00 +/- 0.00) ng/L, and (313.33 +/- 34.06) ng/L respectively; and the concentration of each of the aforementioned expression was (721.67 +/- 66.97) ng/L, (860.33 +/- 315.81) ng/L, (1960.33 +/- 797.90) ng/L, and (278.00 +/- 53.11) ng/L without using silk protein membrane as carriers. The increase of VEGF (F = 168.16, P < 0.0001), EGF (F = 52.76, P < 0.0001), Ang1 (F = 12.47, P = 0.001), and TGF-beta (F = 0.008, P = 0.932) in the Ad-VEGF(165) group was considered statistically significant; however, there was no evident change in the concentration of VEGF (F = 0.071, P = 0.793), EGF (F = 0.563, P = 0.465), Ang1 (F = 0.14, P = 0.714), and TGF-beta (F = 0.008, P = 0.932)expressions in the corneal epithelium cell cultivation supernatant both with or without using silk protein membrane as carriers. CONCLUSION: Same as cell HCECs culturing in the cultivation plate, through SF application, VEGF(165) destination gene could be high-level expressed in the supernatant having which the HCECs is cultured on SF, and in addition, the angiogenesis-related cytokines content of Ang1, EGF, and TGF-beta autocrine in the HCECS cultivation supernatant could be high-level expressed as well.

Cytocompatibility of regenerated silk fibroin film: a medical biomaterial applicable to wound healing.

OBJECTIVE: To explore the feasibility of using regenerated silk fibroin membrane to construct artificial skin substitutes for wound healing, it is necessary to evaluate its cytocompatibility. METHODS: The effects of regenerated silk fibroin film on cytotoxicity, adhesion, cell cycle, and apoptosis of L929 cells, growth and vascular endothelial growth factor (VEGF) expression of ECV304 cells, and VEGF, angiopoietin-1 (Ang-1), platelet-derived growth factor (PDGF) and fibroblast growth factor 2 (FGF2) expression of WI-38 cells were assessed by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, viable cell counting, flow cytometry (FCM), and enzyme-linked immunosorbant assay (ELISA). RESULTS: We showed that the regenerated silk fibroin film was not cytotoxic to L929 cells and had no adverse influence on their adhesion, cell cycle or apoptosis; it had no adverse influence on the growth and VEGF secretion of ECV304 cells and no effect on the secretion of VEGF, Ang-1, PDGF and FGF2 by WI-38 cells. CONCLUSION: The regenerated silk fibroin film should be an excellent biomaterial with good cytocompatibility, providing a framework for reparation after trauma in clinical applications.