Chrysin attenuates diabetes-induced retinal injury by inhibiting microglial GBP3/NLRP3/GSDMD-mediated pyroptosis.

Abstract

Background: This study was designed to investigate whether chrysin, a natural flavone, alleviates experimental diabetic retinal disease and to define a microglia-centered mechanism involving guanylate-binding protein 3 (GBP3) and NLR family pyrin domain containing 3 (NLRP3)-gasdermin D (GSDMD) pyroptosis signaling.

Methods: Streptozotocin (STZ)-diabetic mice received vehicle or chrysin for 4 weeks, followed by assessment of fasting blood glucose, serum caspase-1 and interleukin-1β (IL-1β) levels, retinal histology, Evans blue leakage, and retinal immunofluorescence for glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (IBA-1), with apoptosis measured by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). In vitro, BV2 microglia were exposed to high glucose with vehicle or chrysin. Cell viability (Cell Counting Kit-8), oxidative stress (reactive oxygen species and malondialdehyde), and pyroptosis-associated markers were analyzed by Western blotting, reverse transcription quantitative polymerase chain reaction (RT-qPCR), and immunofluorescence. RNA sequencing (RNA-seq) profiled transcriptional responses, and small interfering RNA (siRNA) was used to knock down GBP3.

Results: In STZ-diabetic mice, chrysin reduced fasting glucose and circulating caspase-1 and IL-1β, partially preserved retinal thickness, and decreased vascular leakage. Chrysin attenuated GFAP upregulation, reduced IBA-1 signals, and lowered TUNEL-positive cells. In BV2 cells, chrysin improved viability, reduced oxidative stress, and suppressed NLRP3-GSDMD activation. RNA-seq highlighted chrysin-responsive pyroptosis signatures and identified GBP3 as a regulated node. GBP3 knockdown reduced high-glucose-associated NLRP3 and Gsdmd expression and diminished GSDMD cleavage.

Conclusions: Chrysin protects the diabetic retina and suppresses microglial pyroptosis via a GBP3-linked NLRP3-GSDMD axis.