ObjectiveTo investigate the effects of transforming growth factor-β (TGF-β) in choroidal neovascularization (CNV) induced by laser in mice. Methods Eighty male C57BL/6J mice at the age of 6-8 weeks old were randomly divided into the normal control, photocoagulation model, photocoagulation with phosphate buffered saline (PBS control group) and photocoagulation with TGF-β receptor inhibitor groups (TGF-β receptor inhibitor group), twenty mice of each group. Fundus argon laser photocoagulation was performed in the photocoagulation model group, PBS control group and TGF-β receptor inhibitor group to induce CNV. One week, two, three and four weeks after the laser procedure, fundus fluorescein angiography (FFA) was carried out in the normal control or photocoagulation model groups to observe CNV formation dynamically. Western blot was used to analyze the expressions of TGF-β in the retina from the mice of normal control or photocoagulation model groups, and VEGF or TNF-α in the retina of normal control, PBS control or TGF-β receptor inhibitor groups. The CNV areas of each group were evaluated by using fluorescein stain on retinal pigment epithelium (RPE)/choroid flat mounts after two weeks of photocoagulation. ResultsThe FFA results showed the retinal vessels centered on the optic disc and arranged radially, while the choroidal vascular present network distribution in the normal control mice. Significant leakage of fluorescein showed discoid strong fluorophore in photocoagulation sites of retina at one week after photocoagulation. The quantitative analysis results of Western blot demonstrated that the TGF-β protein expression levels in retina of photocoagulation model mice gradually increased with time passing. The protein expression levels of TGF-β were significant differences in the photocoagulation model group comparing with the normal control group (F=13.042, P < 0.05). The protein expression levels of TNF-α (F=14.721, 17.509) and VEGF (F=18.890, 11.251) increased significantly in retina of PBS control or TGF-β receptor inhibitor groups when compared with that of normal control group at one week, two, three and four weeks after photocoagulation, and the differences were both statistically significant (P < 0.05). Compared with PBS control group, the protein levels of TNF-α and VEGF in retina from TGF-β receptor inhibitor group were significantly reduced, the differences was statistically significant (F=21.321, 16.160, P < 0.05). Two weeks after laser photocoagulation, a distinct reduction in CNV lesion size in the TGF-β receptor inhibitor group mice when compared to PBS or normal control groups, the differences was statically significant (F=4.482, P < 0.05). ConclusionTGF-β may promote CNV formation by up-regulating both TNF-α and VEGF protein expressions, the application of its specific inhibitor is able to reduce CNV progression.