Qingguang’An II decoction attenuates retinal ganglion cell pyroptosis in glaucoma via inhibition of the TRPV4/NF-κB signaling pathway

Ethnopharmacological relevance

Glaucomatous optic neuropathy (GON), characterized by the progressive degeneration of retinal ganglion cells (RGCs), is the primary pathological basis of irreversible visual impairment in glaucoma. Qingguang’An II decoction (QGAII), a traditional Chinese medicine formula with decades of clinical application, has been shown to promote optic nerve repair and preserve the visual field in patients with GON. Nevertheless, the precise mechanisms underlying the neuroprotective effects of QGAII remain incompletely understood.

Aim of the study

This study aimed to investigate the specific molecular mechanisms by which QGAII mitigates RGC pyroptosis through the targeted modulation of the TRPV4/NF-κB signaling pathway.

Materials and methods

The neuroprotective effects of QGAII were evaluated both in vivo using a DBA/2J mouse model of chronic ocular hypertension and in vitro using a novel cell model of glaucomatous injury. In vivo, the effect of QGAII intervention was assessed by hematoxylin and eosin (H&E) staining and transmission electron microscopy (TEM). The mechanism of action was further investigated by immunofluorescence, flow cytometry, Western blot (WB), qPCR, and ELISA. In vitro, a novel glaucomatous cell injury model was established by combining continuous hydrostatic pressure (CHP) and oxygen-glucose deprivation (OGD). Liposome transfection was employed to explore the roles of TRPV4, NF-κB, and GSDMD. Subsequently, QGAII was administered to this injury model, and its effects were analyzed using a cell counting kit-8 (CCK-8), flow cytometry, scanning electron microscopy (SEM), immunofluorescence, WB, qPCR, and ELISA to clarify its role in attenuating pyroptosis via the TRPV4/NF-κB signaling pathway.

Results

In vivo, H&E staining and TEM showed that QGAII exerted a protective effect on RGCs in the retina of DBA/2J mice, and this effect was linked to a reduction in RGC pyroptosis. Further analysis showed that QGAII attenuated RGC pyroptosis in DBA/2J mice, potentially through the TRPV4/NF-κB signaling pathway. In vitro, we first established that the cell injury model, induced by CHP and OGD, exhibited a GSDMD-dependent pyroptotic phenotype. This process was confirmed to be regulated by the TRPV4/NF-κB signaling pathway. Subsequent QGAII intervention reduced the incidence of RGC pyroptosis. This protective effect was mediated by the inhibition of the TRPV4/NF-κB signaling pathway, as confirmed by immunofluorescence, WB, qPCR, and ELISA.

Conclusion

QGAII suppresses RGC pyroptosis through the targeted modulation of the TRPV4/NF-κB signaling pathway, providing effective optic neuroprotection for the therapeutic management of GON.