LAUSR

AIM To investigate whether anti-placental growth factor (PGF) can inhibit subretinal fibrosis and whether this effect is mediated by the inhibitory effect of PGF on epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells. METHODS Subretinal fibrosis model was established in laser induced choroidal neovascularization (CNV) mice on day 21 after laser photocoagulation. Immunofluorescence staining (IFS) of cryosections and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression of PGF. IFS of whole choroidal flat-mounts was used to detect the degree of subretinal fibrosis. IFS of cryosections and ELISA were used to detect the expression of EMT related indicators in subretinal fibrosis lesions. RESULTS The expression of PGF protein in subretinal fibrosis lesions was significantly up-regulated (P<0.05), and mainly co-stained with pan-cytokeratin labeled RPE cells. Intravitreal injection of anti-PGF neutralizing antibody reduced the area of subretinal fibrosis and the ratio of fibrotic/angiogenic area significantly at the concentrations of 0.25, 0.5, 1.0, and 2.0 µg/µL (all P<0.05). The expression of E-cadherin in the local RPE cells decreased, while α-SMA increased significantly in subretinal fibrosis lesions, and the application of anti-PGF neutralizing antibody could reverse these changes (P<0.05). CONCLUSION The expression of PGF is up-regulated in the lesion site of subretinal fibrosis and mainly expressed in RPE cells. Intravitreal injection of anti-PGF neutralizing antibody can significantly inhibit the degree of subretinal fibrosis in CNV mice, and this effect may be mediated by the inhibition of PGF on EMT of RPE cells.