Fig. 3

Mdivi-1 rescues AβO-induced cognitive impairment, defective mitochondrial fission protein expression, and inflammation in mice and prevents synapse loss in hippocampal neurons. a Representative images of cultured hippocampal neurons exposed to 500 nM AβOs or vehicle for 24 h and immunolabeled for synaptophysin (green) or PSD-95 (red). Synapses evidenced by colocalized puncta, appear in yellow. Where indicated, neurons were pre-incubated for 1 h with mdivi-1 (25 μM). Scale bar: 20 μm. b, d Integrated immunoreactivities, for synaptophysin (b), PSD-95 (c), and number of colocalized synaptophysin/PSD95 puncta (d). Data are expressed as means ± SEM from 4 experiments from independent cultures (30 images analyzed per experimental condition per independent culture). *p < 0.05, **p < 0.01 compared with vehicle or AβOs; two-way ANOVA followed by Holm-Šidak post hoc test. e Experimental design of the treatment of mdivi-1. Male C57BL/6 mice received an i.c.v. injection of AβOs (100 pmol) or vehicle. Twenty-four hours after i.c.v. injection of AβOs (100 pmol) or vehicle, animals underwent the NOR. The percentage of time exploring familiar or novel objects in the test session is shown in f. Mdivi-1 (40 mg/kg, i.p.) treatment began on day 3 and lasted for 7 days. On day 10, animals underwent NOR again. g after the mdivi-1 (40 mg/kg, i.p.) treatment. h 11 days after i.c.v. injection of AβOs (100 pmol), the same animals were trained in the contextual fear conditioning task. The percentage of freezing behavior in this task is shown. In f (n = 17–18 animals per group) and g (n = 9–10 animals per group), data are expressed as means ± SEM of the percentage of time spent on each object presented at the test session and *p < 0.05, compared with a hypothetical value of 50% of exploration time; one-sample Student’s t test. In h, data are expressed as means ± SEM (n = 9–10 animals per group). **p < 0.01, *p < 0.05, compared with vehicle or AβOs; two-way ANOVA followed by Holm-Šidak post hoc test. i Drp1 levels in the hippocampi of mice 12 days after i.c.v. injection of AβOs (100 pmol). Following AβO injection, animals were treated for 7 days with saline or mdivi-1 (40 mg/kg; i.p.; n = 8-9 animals/group). *p < 0.05 compared with vehicle or AβOs, two-way ANOVA followed by Holm-Šidak post hoc test