Effects of mechanical stimulation on basic fibroblast growth factor expression of corneal fibroblasts / 医用生物力学

Objective To investigate the effect of different mechanical environment ( in vivo and in vitro) on expression of basic fibroblast growth factor (bFGF) and explore the role of mechanical stimulation in corneal tissue repair after laser assisted in situ keratomileusis (LASIK) surgery. Methods Animal models by LASIK surgery were established to keep the corneas under different mechanical environment. The experimental animals were killed at the first week or the first month after LASIK surgery to obtain the corneas. In addition, the primary corneal fibroblasts were subjected to cyclic mechanical stretch (0.1 Hz; 5%, 10%, 15% stretch; 6 h or 24 h) using Flexcell 4 000 tension system. Expression of bFGF was determined by ELISA method. Results At the first week after LASIK surgery, expression of bFGF was increased significantly in 30% group (residual stroma bed accounting for 30% of the whole cornea), as compared with the control group (P<0.05), and then it was decreased to the normal level in all groups at the first month after LASIK surgery. Analysis on the same surgery method at different time showed that there were significant differences only in 30% group at the first week and month (P<0.05). Cyclic stretch experiment in vitro indicated that bFGF expression in 15% stretch group was significantly increased after 6 h than that in the control group (P<0.05), with a significant decrease after 24 h (P<0.05). Conclusions Mechanical stimulation can regulate bFGF expression of corneal tissues and corneal frbroblasts, and bFGF plays a positive role in the early corneal tissue repair after LASIK surgery.

Peptidoglycan from Staphylococcus aureus induces the overexpression of TRLs 1-8 mRNA in corneal fibroblasts, but its lipoteichoic acid and muramyl dipeptide only induced the overexpression of TLR5 or TRL9

Lipopolysaccharide induces TLR-1-8 mRNAs over-expression in corneal fibroblast. Analyzing if other TLR-ligands can do the same, we found that peptidoglycan does, but not muramyldipeptide, lipoteichoic acid and polyI:C. This suggests that the recognition of lipopolysaccharide and peptidoglycan is enough to alert these cells against microorganisms through the over-expression of the majority TLRs.

Expression of Local Immunosuppressive Factor, Indoleamine 2,3-dixygenase, in Human Coreal Cells

PURPOSE: To identify the localization of indoleamine 2,3-dioxygenase (IDO) in human corneal cells and to evaluate its ability to act as a local immunosuppressive factor. METHODS: The expression profile of IDO was obtained with RT-PCR and Western blot of in a primary culture of human corneal cells (fibroblasts, epithelial cells and endothelial cells). In order to investigate the immunosuppressive function of IDO, immune cells were cultured in a human corneal cell-conditioned medium, and their prolifleration was identified by the MTT assay. Moreover, apoptotic effects of IDO in immune cells treated with IFN-gamma were also investigated with apoptosis ELISA. RESULTS: Among the three different types of human corneal cells analyzed, mRNA and protein expression of IDO was observed only in human corneal fibroblasts. Immune cells cultured in a human corneal fibroblast-conditioned medium showed inhibited proliferation. Moreover, IFN-gamma-induced expression of IDO significantly enhanced apoptotic ability in a dose-depandant manner. CONCLUSIONS: Our results suggest that human corneal fibroblasts are relatively immuno-resistant and that expression of IDO may be one of the factors involved in the immune tolerance observed in corneal grafts.

Hydroxyapatite modified titanium promotes superior adhension and proliferation of corneal fibroblast in comparison with pure titanium / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To determine whether hydroxyapatite modified titanium promotes superior adhension and proliferation of rabbit corneal fibroblast in comparison with pure titanium.METHODS: We used bioactive hydroxyapatite to modify titanium surfaces. Fourth passage fibroblasts of rabbit cornea were seeded on hydroxyapatite modified titanium surfaces, pure titanium and glass surfaces. Cell adhension, proliferation and morphology were detected at 24 hours, 48 hours, and 72hours using a acridine orange stain. Further studies of cell morphology were performed using scanning electron microscopy.RESULT: Ceil counts were significantly greater on hydroxyapatite modified titanium surfaces at each time point(P＜0.05).At 24 hours, cell spreading was greater on hydroxyapatite-coated titanium and glass than on the pure titanium. At 72 hours, compared with pure titanium and glass surfaces, the cells on hydroxyapatite modified titanium surfaces had greater spreading area and longer stress fibers.CONCLUSIONS: Hydroxyapatite modified titanium promotes superior adhension and proliferation of rabbit corneal fibroblast in comparison with pure titanium.

Cell Death of Corneal Fibroblasts Induced by Tumor Necrosis Factor-alphaand Interferon-gamma

PURPOSE: To evaluate the effect in the cell death of corneal fibroblasts when TNF-alphaand INF-gamma were given together. METHODS: Fibroblasts harvested from the human cornea were cultured in DMEM, then, nothing(control: Group 1), TNF-alphaonly(50 ng/ml : Group 2), INF-gammaonly(1.0 x 10(3)u/ml : Group 3), and a combination of both(Group 4) were added. We assessed the cell viability of the each group by the trypan blue exclusion assay at 4, 8, 12, 24, 48 hours after addition of cytokines. RESULTS: The cell viability at 48 hour after treatment was 94.27% in group 1, 90.68%(p=0.09) in group 2, 93.31%(p=0.45) in group3, and there was no statistical difference among the groups. Statistically signi-ficant decrease of the cell viability was achieved in group 4(82.86%, p=0.002). CONCLUSIONS: Cell death of human corneal fibroblasts had been increased after treatment with a combination of TNF-alphaand INF-gamma. These findings suggest that there could be some kind of interaction among the cytokines.