Effects of extremely low frequency electromagnetic fields on human retinal pigment epithelium cells

Abstract

Objective To investigate pathological changes in the molecules of human retinal pigment epithelium (hRPE) exposed to an extremely low frequency electromagnetic field (ELF-EMF) , and study its possible significance in the occurrence and development of myopia. Methods In this experimental study, the experimental group was composed of hRPE exposed to 50 Hz electromagnetic fields; the untreated group was composed of hRPE without exposure. The changes in hRPE cell morphology were observed and cell proliferation in hRPE was measured by a CCK8 assay. The expressions of matrix metallo-proteinase-2 (MMP-2) , tissue inhibitor of metalloproteinase 2 (TIMP-2) , transforming growth factor-β2 (TGF-β2) and fibroblast growth factor 2 (FGF-2) mRNA in hRPE were detected by reverse transcription-polymerase chain reaction (RT-PCR). The concentrations of TGF-β2 and FGF-2 in the culture medium of hRPE were assayed by enzyme-linked immunosorbent assay (ELISA). The difference between the two group using independent t test. Results hRPE cell morphology changed, and the proliferation of hRPE was inhibited (t=-7.069, -3.652, -6.974, P<0.05). The mRNA expressions of MMP-2, TIMP-2 and TGF-β2 were up-regulated significantly (t=10.562, 6.277, 4.940, P<0.01). However, the mRNA expression of FGF-2 was down-regulated significantly (t=-6.905, P<0.01). The results of ELISA indicated that after exposure to ELF-EMF, the expression of TGF-β2 in hRPE supernatant medium was up-regulated significantly (t=-4.079, P<0.05). However, the expression of FGF-2 in hRPE supernatant medium was down-regulated (t=4.441, P<0.05). Conclusion ELF-EMF changed the proliferation of hRPE, and also changed the expressions of MMP-2, TIMP-2, TGF-β2 and FGF-2 mRNA in hRPE, which might induce the occurrence of myopia through pathological changes in the molecules of hRPE. Key words: Radiation, ionizing; Pigment epithelium, eye; Myopia; Matrix metallo-proteinase-2; Transforming growth factor beta; Fibroblast growth factor 2