Protective effects of safranal on diabetic retinopathy in human microvascular endothelial cells and related pathways analyzed with transcriptome sequencing.

Aim: To determine the effect of safranal on diabetic retinopathy in vitro and its possible mechanisms. Methods: We used human retinal microvascular endothelial cells (HRMECs) to test the influence of safranal in vitro. High glucose damage was established and an safranal was tested at various concentrations for its potential to reduce cell viability using the MTT assay. We also employed apoptosis detection, cell cycle detection, a transwell test, and a tube formation assay to look into safranal's inhibitory effects on high glucose damage at various doses. Furthermore, mRNA transcriptome sequencing was performed. mRNA expression levels in a high glucose damage model, a high glucose damage model treated with safranal, and a blank control were compared to find the possible signaling pathway. Western blotting was used to confirm the expressions of several molecules and the levels of phosphorylation in each for the newly discovered pathway. Results: Cell proliferation was inhibited under a high glucose condition but could be protected by safranal at different concentrations (P<0.001). Flow cytometry results suggested safranal also protected cells from apoptosis (P=0.006). A transwell test demonstrated reduced invasiveness of safranal-treated cells in a high glucose condition (P<0.001). In a tube formation investigation, there were noticeably more new branches in the high gloucose group compared to a high glucose treated with safranal group (P<0.001). In mRNA expression patterns on transcriptome sequencing, the MAPK signaling pathway showed an expression ratio. With western blotting, the phosphorylation level of p38-AKT was elevated under a high glucose condition but could be inhibited by safranal. The expression of molecules associated with cell adhesion, including E-cadherin, N-cadherin, Snail, Twist, and fibronectin also changed significantly after safranal treatment under a high glucose condition. Conclusion: Safranal can protect diabetic retinopathy in vitro, and the p38-AKT signaling pathway was found to be involved in the pathogenesis of diabetic retinopathy and could be inhibited by safranal. This pathway may play a role by influencing cell migration and adhesion.

Inhibitory effects of safranal on laser-induced choroidal neovascularization and human choroidal microvascular endothelial cells and related pathways analyzed with transcriptome sequencing.

AIM: To determine the effects of safranal on choroidal neovascularization (CNV) and oxidative stress damage of human choroidal microvascular endothelial cells (HCVECs) and its possible mechanisms. METHODS: Forty-five rats were used as a laser-induced CNV model for testing the efficacy and safety of safranal (0.5 mg/kg·d, intraperitoneally) on CNV. CNV leakage on fluorescein angiography (FA) and CNV thickness on histology was compared. HCVECs were used for a H2O2-induced oxidative stress model to test the effect of safranal in vitro. MTT essay was carried to test the inhibition rate of safranal on cell viability at different concentrations. Tube formation was used to test protective effect of safranal on angiogenesis at different concentrations. mRNA transcriptome sequencing was performed to find the possible signal pathway. The expressions of different molecules and their phosphorylation level were validated by Western blotting. RESULTS: On FA, the average CNV leakage area was 0.73±0.49 and 0.31±0.11 mm2 (P=0.012) in the control and safranal-treated group respectively. The average CNV thickness was 127.4±18.75 and 100.6±17.34 µm (P=0.001) in control and safranal-treated group. Under the condition of oxidative stress, cell proliferation was inhibited by safranal and inhibition rates were 7.4%-35.4% at the different concentrations. For tube formation study, the number of new branches was 364 in control group and 35, 42, and 17 in 20, 40, and 80 µg/mL safranal groups respectively (P<0.01). From the KEGG pathway bubble graph, the PI3K-AKT signaling pathway showed a high gene ratio. The protein expression was elevated of insulin receptor substrate (IRS) and the phosphorylation level of PI3K, phosphoinositide-dependent protein kinase 1/2 (PDK1/2), AKT and Bcl-2 associated death promoter (BAD) was also elevated under oxidative stress condition but inhibited by safranal. CONCLUSION: Safranal can inhibit CNV both in vivo and in vitro, and the IRS-PI3K-PDK1/2-AKT-BAD signaling pathway is involved in the pathogenesis of CNV.