Abstract
Purpose :
At present, anti-vascular endothelial growth factor (VEGF) injection is the most effective therapy for retinal neovascularization. However, infection risk and economic burdens restricted the applications of anti-VEGF. This study was to investigate the effect of FK506 on hypoxia-induced inflammation and retinal neovascularization in both mouse retinal microvascular endothelial cells (mRMECs) and oxygen-induced retinopathy (OIR) mouse model.
Methods :
mRMECs were treated with FK506 at different concentrations (0.1μM, 1 μM and 10 μM) after suffering from hypoxia, and OIR mice were intraperitoneally injected with FK506 (5 mg/kg) from P12 to P17. Trans-epithelial electrical resistance (TEER) and cell permeability were performed to measure the integrity of cell tight junctions. The protein expressions were identified by western blot and immunofluorescent staining. And the concentrations of inflammatory cytokines were measured by quantitative PCR and ELISA. Furthermore, in OIR mice, the areas of avascular and neovascular were quantified by immunofluorescent staining on whole-mount retina.
Results :
In mRMECs, TEER value was decreased for nearly 30% after hypoxia (P<0.05), but significantly increased 1.7 fold to 3.5 fold with treatment of FK506 (1 μM and 10 μM). ZO-1 protein expression also increased more than 2.5 fold with FK506 treated for 24 h at 1 μM and 10 μM. In opposite, elevated cell permeability in hypoxia group was significantly downregulated 1.8 fold to 2.9 fold. Similarly, concentrations of inflammatory cytokines (VEGF, COX-2, iNOS, MCP-1, IL-6, ICAM-1, VCAM-1) were significantly downregulated after treated with FK506. In OIR mice model, the retinas of OIR mice showed obvious neovasculars and a multiple of neovasculars tufts covering at the leading edge of retinal vessels. However, the areas of neovasculars and neovasculars tufts were significantly reduced with the treatment of FK506. Meanwhile, when treated with FK506, phosphorylated NFATc1 was upregulated more than 2 fold and total NFATc1 was downregulated.
Conclusions :
FK506 suppresses the injury of tight junctions and down-regulates the expression of inflammatory cytokines in hypoxia-induced mRMECs, and inhibits the retinal neovascularization in OIR mice model. These effects of FK506 came into play through CaN-NFATc1 pathways. It suggested that FK506 might be a potentially effective therapy for hypoxia-induced retinal microangiopathy.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.