Quercetin attenuates high glucose-induced injury in human retinal pigment epithelial cell line ARPE-19 by up-regulation of miR-29b.

Quercetin is a kind of distinctive bioactive flavonoid that has potent anti-oxidant, anti-inflammatory and anti-diabetic properties. The present article was designed to check the effect of quercetin on diabetic retinopathy. Adult retinal pigment epithelial cell line (ARPE)-19 cells were pre-treated with quercetin and then stimulated by high glucose. Cell damage was evaluated by CCK-8 assay, flow cytometer, quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay, 2,7-dichlorofluorescein diacetate probe and western blot. The association between quercetin and miR-29b expression as well as the downstream pathways was studied by qRT-PCR and western blot. Pre-treating ARPE-19 cells with quercetin clearly attenuated high glucose-induced viability loss, apoptosis, MCP-1 and IL-6 overproduction and reactive oxygen species (ROS) generation. Quercetin down-regulated p53, Bax and cleaved-caspase-3 expression, while up-regulated CyclinD1, CDK4 and Bcl-2. miR-29b was low expressed in high glucose-treated cell, but quercetin elevated its expression. Moreover, the protective action of quercetin towards ARPE-19 cells was attenuated when miR-29b was suppressed. Also, quercetin promoted PTEN/AKT pathway, while inhibited NF-κB pathway via a miR-29b-dependent way. These data illustrated quercetin possibly possess the anti-diabetic retinopathy potential, as quercetin clearly attenuated high glucose-evoked damage in ARPE-19 cells. The protective action of quercetin may due to its regulation on miR-29b expression as well as PTEN/AKT and NF-κB pathways.