Fig. 7. MIF nuclease activity is critical for DNA damage and ischemic neuronal cell death in vivo.

(A) Representative images of triphenyl tetrazolium chloride staining of MIF WT, KO, and KO mice that were injected with AAV2-MIF WT, E22Q, or E22A 24 hours after 45 min of middle cerebral artery occlusion (MCAO). (B to D) Quantification of infarction volume in cortex, striatum, and hemisphere 1 day or 7 days after 45-min MCAO. WT MCAO (n = 29); KO MCAO (n = 20); KO-WT MCAO (n = 23). KO-E22Q (n = 22) and KO-E22A MCAO (n = 19). *P < 0.05, ***P < 0.001, versus KO group at the same time point; ^##P < 0.01, ^###P < 0.001, the same group at 7 days versus at 1 day after 45-min MCAO, one-way ANOVA. (E to G) Neurological deficit was evaluated by [(E) and (F)] open field on a scale of 0 to 5 and (G) corner test evaluated by percentage of right turns at 1 day, 3 days, or 7 days after MCAO surgery. WT MCAO (n = 16); KO MCAO (n = 12); and KO-WT MCAO (n = 16). KO-E22Q MCAO (n = 16) and KO-E22A MCAO (n = 16). Means ± SEM. *P < 0.05, ***P < 0.001, one-way ANOVA in (E) and (G). **P < 0.01, two-way ANOVA in (F), WT and KO-WT versus KO, KO-E22Q, and KO-E22A at different time points. (H) DNA fragmentation determined by pulsed-field gel electrophoresis in the penumbra 1 day, 3 days, or 7 days after 45-min MCAO surgery in MIF WT, KO, and KO mutant mice, which were injected with AAV2-MIF WT, E22Q, or E22A. WT MCAO (n = 15); KO MCAO (n = 15); and KO-WT MCAO (n = 15). KO-E22Q (n = 15) and KO-E22A MCAO (n = 15). (I) Quantification of noncleaved genomic DNA. Means ± SEM. ****P < 0.0001, versus its sham treatment group, one-way ANOVA.