Investigation of the use of apigenin, a natural molecule, in the treatment of proliferative vitreoretinopathy in an in vitro model

Proliferative vitreoretinopathy is characterized by cell migration and proliferation into the subretinal space, retinal surface and vitreous. Cell proliferation is associated with damage to the retina, disruption of the blood-retinal barrier, and the interaction between regulatory growth factors. This condition represents excessive and abnormal wound healing resulting in membrane formation on both surfaces of the retina. It usually occurs after prolonged retinal detachment and detachment surgery. Currently, the only treatment for proliferative vitreoretinopathy is surgery, and there are no pharmacological agents effective in preventing its development or treating the disease. In order to effectively treat proliferative vitreoretinopathy, it is necessary to understand the process of formation of this disease. Apigenin is a flavonoid with antioxidative, anti-inflammatory, antimutagenic, antiproliferative and antineoplastic properties found in various plants. Its effectiveness on cell proliferation and migration caused by transforming growth factor-β2 is unknown. In this study, the potential effect of apigenin on retinal pigment epithelial cell proliferation and epithelial-mesenchymal transformation was investigated. For this purpose, viability analysis of the cells was performed with the MTT test. After determining the appropriate doses to use, serum-starved ARPE-19 cells were treated with 10 ng / ml Transforming growth factor-β2 alone, then co-treated with 1,56 µM apigenin for 48 hours. mRNA and protein expressions were evaluated by RT-qPCR and Western blot, respectively. Apoptosis was detected by image-based cytometry. The effect of treatment on cell migration was evaluated by the wound healing experiment. In the statistical analysis of the study, analysis of variance was used for the differences between the groups, followed by Duncan's multiple comparison test for multiple comparisons. In this study, it has been shown that apigenin inhibits transforming growth factor-β2-induced (TGF- β2) retinal pigment epithelial cell proliferation by inducing apoptosis. It has been revealed that the mRNA expressions of fibronectin, N-cadherin and vimentin, which are mesenchymal markers, are up-regulated by TGF-β2 and significantly down-regulated by apigenin treatment. Apigenin application significantly suppressed the effects of TGF-β2 by down-regulating the expression of the transcription factors Twist, Snail and ZEB1 induced by Transforming growth factor-β2. It was also concluded that apigenin significantly inhibited the expression of Matrix metalloproteinase1, 2 and 7. Apigenin treatment also suppressed NF-κB and α-SMA signaling, as shown by Western blotting. While the expressions of E-cadherin, which are epithelial markers, are down-regulated by TGF-β2, it has been shown that their expressions are up-regulated after treatment with apigenin. These results indicate that apigenin may inhibit the proliferation and differentiation of retinal pigment epithelial cells into fibroblast-like cells. Therefore, we think that apigenin may have potential therapeutic value in the treatment of proliferative vitreoretinopathy.