ABSTRACT
BackgroundThe effects of extremely low frequency electromagnetic fields (ELF-EMFs) on public health have attracted wide attentions.The association of the thermal effect of ELF-EMFs with cancer and ocular tissue damage has been of concern.However,the pathological changes of scleral tissue after exposure to ELF-EMFs as well as the relationship between these changes and myopia are still poorly understood.ObjectiveThe present study was to investigate the molecular pathological changes of human fetal scleral fibroblasts (HFSFs) after exposure to ELF-EMFs in vitro and to explore the possible mechanism in the occurrence and development of myopia.MethodsHFSFs were cultured and passaged and then exposed to 50 Hz electromagnetic fields,and HFSFs that did not receive the irradiation of ELF-EMFs were used as the control group.The expression of collagen type Ⅰ (COL1A1 ) mRNA and matrix metalloproteinase-2 (MMP-2) mRNA in cultured HFSFs were detected by real-time qualitative polymerase chain reaction (real-time PCR) under different magnetic field intensites (0,0.1,0.2,0.5,1.0 mT) and different exposure time (0,6,12,24,36,48 hours).Cell proliferation assay of HFSFs was detected by the cell counting kit 8 ( CCK8 ) assay.The expression levels of COL1 A1 and MMP-2 proteins in HFSFs were further confirmed by immunofluorescence staining.Results The expression of COL1A1 mRNA was significantly down-regulated under the exposure of 0.2 mT ELF-EMFs for 6 hours,in comparison with the control group;moreover,it decreased in parallel with the increased of flux density (0.099±0.008 vs.0.050±0.004) (P =0.009 ).The expression of MMP-2mRNA was up-regulated conspicuously after exposure to 0.1 mT ELF-EMFs for 24 hours,and it increased with exposure time in comparison with the control group ( 0.009 ±0.001 vs.0.018±0.003 ) ( P =0.038 ).Proliferation of HFSFs (A450) was inhibited following the exposure to 0.2 mT ELF-EMFs for 24 hours in comparison with the control group (P =0.009 ).The expression of COL1 A1 in the experimental group was decreased,compared with the control group,but the expression of MMP-2 was increased.ConclusionsELF-EMFs inhibit the proliferation of HFSFs and expression of COL1 A1 in HFSFs,which might be one of the reasons for the development of myopia.
ABSTRACT
Objective:To compare the changes in tear film stability and corneal sensitivity after laser-assisted subepithelial keratectomy (LASEK) and laser in situ keratomileusis (LASIK). Methods: Forty eyes of 20 patients underwent LASIK and 40 eyes of 20 patients underwent LASEK to correct mypia. The patients were observed for corneal sensitivity, tear break-up time (BUT) and Schirmer test under local anesthesia before and 1, 3 and 6 months after operation. The results were analyzed statistically. Results: The tear film stability and corneal sensitivity were decreased to some extent in both groups after operation. Compared with before operation, there were significant differences in corneal sensitivity 1, 3 and 6 months after operation and in BUT 1, 3 months after operation in LASIK group (P0.05). Conclusion: Both LASIK and LASEK influence the corneal sensitivity and tear film stability after operation; the influence diminishes with the recovery of the cornea. The influence in LASIK group is more serious and more persistent than that in LASEK group.