title: Biological Modulation of Mouse RPE Cells in Response to Subthreshold Diode Micropulse Laser Treatment.
abstract: Many clinical trials have demonstrated the effectiveness of subthreshold phototherapy with no visible damage in retinal vascular diseases, such as diabetic retinopathy. We aimed primarily to investigate the effect of subthreshold diode micropulse laser (SDM) treatment on mouse retinal pigmented epithelium (RPE) cells. The expression of angiogenesis-modulating cytokines in response to SDM was also explored. The least toxic laser dose was selected by measuring cell viability with MTT assay and 5 % duty cycle (DC) was chosen for use in further experiments. RPE cells were treated with laser-induced radiation ranging from 0 to 400 mW for 24 h. The apoptotic rate of RPE cells was assessed by flow cytometry. Expressions of vascular endothelial growth factor A (VEGF-A), transforming growth factor beta (TGF-β), basic fibroblast growth factor (bFGF), and pigment epithelium-derived factor (PEDF) were determined by Western Blotting and real-time PCR, respectively. After 24 h of laser irradiation, cell viability was reduced dose dependently and the effect was significant compared to the controls (P < 0.05). In addition, laser treatment with intensities of 100 and 200 mW with DC of 5 % produced no significant effect on cell viability and apoptosis as compared with the control group (P > 0.05). The protein and mRNA expressions of angiogenic stimulators (VEGF-A, TGF-β, and bFGF) were significantly down-regulated (P < 0.05), whereas those of the angiogenic inhibitor (PEDF) were up-regulated (P < 0.05). No significant difference was found between the cells treated with different intensities of laser radiation (P > 0.05). Our results showed that SDM treatment of the RPE cells suppressed the expression of choroid neovasculization-promoting cytokines and up-regulated the angiogenic inhibitor, PEDF without damaging the cells. Further investigation is needed to understand the mechanism and to optimize the use of SDM as a novel method of treatment for retinal vascular diseases.
authors.affiliation: Southern Medical University, Guangzhou, 510515, Guangdong, China.
authors.forename: Zhouyue
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Ophthalmology, Wuhan General Hospital of Guangzhou Military, Wuhan, 430070, Hubei, China. dryanpingsong@163.com.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Song
authors.affiliation: Department of Ophthalmology, Wuhan General Hospital of Guangzhou Military, Wuhan, 430070, Hubei, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Ophthalmology, Wuhan General Hospital of Guangzhou Military, Wuhan, 430070, Hubei, China.
authors.forename: Zhongshan
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Ophthalmology, Wuhan General Hospital of Guangzhou Military, Wuhan, 430070, Hubei, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Ding
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D015536:Down-Regulation / Q000528:radiation effects; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D005434:Flow Cytometry; D007834:Lasers; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D015843:Serpins / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000528:radiation effects; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
chemical_list: D005136:Eye Proteins; D009414:Nerve Growth Factors; D015843:Serpins; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D000099174:Pigment Epithelium-Derived Factor
keywords: Choroid neovascularization (CNV); Retinal pigmented epithelium (RPE); Retinal vascular disease; Subthreshold diode micropulse laser (SDM)