Qinghua Yure Fang Alleviates Inflammatory Response in Retinal Cells of Diabetic Retinopathy Rats via IL-33/ST2 Pathway
Objective To investigate the effects of Qinghua Yure Fang(QHYRF)on inflammation,apoptosis and oxidative stress in retinal cells of diabetic retinopathy(DR)rats and the mechanism of signaling network.Methods A DR rat model and a cellular model of human retinal microvascular endothelial cells(hRMECs)treated with high glucose were established by streptozotocin(STZ)injection.Retinal tissue was observed using hematoxylin-eosin(HE)staining and transmission electron microscopy.The expression patterns of oxidative stress indexes,pro-inflammatory cytokines and pro-apoptotic proteins in hRMEC were characterized using corresponding kits,enzyme linked immunosorbent assay(ELISA)and western blot.The expression of proteins associated with Interleukin-33(IL-33)/suppression of Tumorigenicity 2(ST2)signaling pathway was analyzed by Western blot.Results HE staining results showed that STZ-treated rats exhibited significant edema,capillary wall thickening,endothelial cell hyperplasia,and fibrous tissue hyperplasia compared with sham-operated rats,all of which could be partially alleviated by QHRYF treatment given in a dose-dependent manner(P＜0.05).Observation of the ultrastructure of the retina showed that STZ-treated rats had increased capillary basement membrane thickness(BMT)values compared with sham-operated rats,while QHRYF treatment decreased BMT values in a dose-dependent manner(P＜0.05).The expression of IL-33 and ST2 was significantly reduced in STZ-treated rats compared with sham-operated rats,and QHRYF treatment increased the expression of IL-33 and ST2 in a dose-dependent manner(P＜0.05).Compared with sham-operated rats,STZ rats showed significantly higher levels of reactive oxygen species(ROS)and MDA and lower levels of SOD in retinal tissues(P＜0.05),all of which were partially reversed by QHRYF in a dose-dependent manner(P＜0.05).The levels of interleukin-6(IL-6),tumor necrosis factor-α(TNF-α),and C-reactive protein(CRP)were significantly increased in cell supernatants of STZ-treated rats,compared with sham-operated rats(P＜0.05).STZ-treated rats injected with QHRYF showed significantly lower expression of IL-6,TNF-α,and CRP in cell supernatants,compared with STZ-treated rats injected with phosphate buffered saline(PBS)(P＜0.05).The expression of the apoptosis-related factor cleaved caspase-3 protein was higher in retinal tissues of STZ-treated rats,compared with sham-operated rats,and QHRYF treatment reduced the expression of this protein in a dose-dependent manner(P＜0.05).Conclusion Our findings suggest that QHYRF alleviates retinal cell inflammation,apoptosis,and oxidative stress in DR rat models by activating the IL-33/ST2 signaling pathway.
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