SRTAW04 treatment increases SIRT1 activity in optic nerves without affecting expression. (a) Control, MHV-free mice were treated with SIRT1 activator SRTAW04 (100 mg/kg/day) for 4 days and sacrificed on the 4th day at indicated time intervals after the final dose (n = 4 per group). Optic nerves were isolated and SIRT1 activity was determined with a fluorometric substrate assay kit. SIRT1 activity was significantly increased (*p < 0.05) 1 hr after SRTAW04 treatment. Increased activity was transient, returning to control levels after 2 hr. (b) SIRT1 activity in the optic nerves of MHV-A59 infected mice after 30 days of SRTAW04 (100 mg/kg/day) treatment (n = 5) showed a significant increase in SIRT1 activity compared to non-infected control (n = 3) (***p < 0.001) and untreated MHV-A59 infected (*p < 0.05) mice (n = 5). (c) The expression level of SIRT1 protein in optic nerves of mice after 30 days with or without treatment showed no significant change (n = 4).