AQP4 and retinal degeneration: Furthermore, hesperetin considerably reduced the retinal levels of inflammatory cytokines including TNF-α and IL-1β and hampered the expression of caspase-3, glial fibrillary acidic protein (GFAP) and aquaporin-4 (AQP4) in retinae which play a key role in retinal degeneration, and prevented the photoreceptor degeneration (65).