Caffeic acid phenethyl ester attenuates nuclear factor‑κB‑mediated inflammatory responses in Müller cells and protects against retinal ganglion cell death.

Glaucoma is characterized by the death of retinal ganglion cells (RGCs) and visual field defects, and is a leading cause of blindness worldwide. Caffeic acid phenethyl ester (CAPE), a natural polyphenolic found in propolis from honeybee hives, can inhibit the activation of nuclear factor kappa light-chain-enhancer of activated B cells (NF-kappa B) and has therapeutic potential in inflammatory disease. The present study used a rat model of optic nerve crush (ONC) injury to investigate the effect of CAPE on glaucoma. The death of RGCs at day 14 was significantly reduced in CAPE-treated animals compared with the non-treated group according to Brn3a and TUNEL staining. In addition, CAPE decreased the severity of inflammation in the retina, reflected by the decreased expression of inflammatory cytokines, including interleukin (IL)-8, IL-6, inducible nitric oxide synthase, cycloooxygenase-2, tumor necrosis factor-alpha and chemokine C-C ligand-2, in CAPE-treated rats. The hypertrophy of astrocytes and Muller cells (gliosis) caused by ONC was also found to be attenuated by CAPE, accompanied by the inhibition of NF-kappa B signaling. Similarly, in vitro, CAPE suppressed the proliferation and migration of primary astrocytes induced by lipopolysaccharide, as well as the activation of NF-kappa B. These results suggest that CAPE protected against RGC and attenuated inflammatory responses in a rat model of ONC by suppressing NF-kappa B activation.