Pterostilbene Protects the Optic Nerves and Retina in a Murine Model of Experimental Autoimmune Encephalomyelitis via Activation of SIRT1 Signaling

Optic neuritis and retinal damage are common manifestations of multiple sclerosis (MS). Pterostilbene (PT) has been used to treat multiple diseases for its anti-inflammatory, anti-apoptosis and neuroprotective activities. This study aimed to investigate whether PT exerts a therapeutic effect on optic neuritis and retinal damage triggered by MS. Here, experimental autoimmune encephalomyelitis (EAE), an experimental model for MS, was induced in female C57BL/6 mice by immunizing with MOG35-55 peptide and treating with pertussis toxin. The mice were intraperitoneally injected with 20 mg/kg and 40 mg/kg PT once daily for 25 days at 24 h post immunization. We found that PT alleviated EAE severity and delayed EAE onset. Moreover, PT mitigated EAE-induced optic nerves and retinal inflammation, as indicated by the decreased Iba-1+ and GFAP+ cells and mRNA levels of interleukin-6, tumor necrosis factor-α and interleukin-1β and the increased Iba-1+sirtuin 1 (SIRT1)+ and GFAP+SIRT1+ cells in the optic nerves and retina. PT also protected the optic nerves against demyelination and axonal loss and the retina against disorders in retinal morphology and apoptosis of retinal ganglion cells. High-dose PT had a more significant effect on protection of the optic nerves and retina in EAE than low-dose PT. In addition, PT activated SIRT1 signaling in the optic nerves and retina. Notably, EX-527, an inhibitor of SIRT1, reversed the effect of high-dose PT on the optic nerves and retina, indicating that PT exerted the protective effect via activating SIRT1 signaling. This study provides a potential candidate for treating MS.