The effects of delayed administration of r-PGRN 6 h after transient MCAO. (A) Protocol for surgery and PGRN administration. Injections (i.c.v.) of either vehicle or r-PGRN (1.0 ng) were administered 6 h after the MCAO procedure. All assessments were performed at 24 h after the induction of 2 h of transient MCAO. (B) Administration of 1 ng of r-PGRN 6 h after MCAO did not reduce the infarct volume assessed at 24 h after the induction of 2 h of MCAO; (C) however, it significantly reduced brain edema. N.S. not significant; * P <0.05 vs. vehicle-treated group; Student's t-test; n = 8 or n = 9 for each group. i.c.v., intracerebroventricular; MCAO, middle cerebral artery occlusion; PGRN, progranulin; r-PGRN, recombinant-progranulin.