Protective effect and mechanism of nicotinamide adenine dinucleotide against optic neuritis in mice with experimental autoimmune encephalomyelitis

•NAD+ intervention before the onset of EAE symptoms delayed signs of EAE.•NAD+ intervention alleviated EAE-induced inflammation in the optic nerve.•NAD+ intervention partly restored EAE-mediated demyelination and axonal loss in the optic nerve.•NAD+ intervention mitigated EAE-induced inflammation and RGC apoptosis in the retina.•NAD+ intervention enhanced SIRT1 signaling in the optic nerve and retina.