Figure 2. Lentiviral-mediated expression of neuritin attenuates learning and memory impairments in Tg2576 mice.

(A) A schematic of the experimental scheme is shown. Viral particles of EGFP or neuritin lentiviral vector were injected into the dentate gyrus of 13-month-old wt or Tg2576 mice using a stereotaxic apparatus. (B) The Morris water maze training test was performed over 5 days. 4 weeks after the lentiviral-mediated expression of EGFP or neuritin, we tested the wt-EGFP (n = 7), wt-neuritin (n = 10), Tg2576-EGFP (n = 10) or Tg2576-neuritin (n = 8) injected mice for spatial learning and memory capability using the Morris water maze test. The 13-month-old Tg2576 mice with EGFP expression showed longer latency times than the remaining 3 groups of mice including the age-matched Tg2576 mice with neuritin expression at the fifth training days (**p<0.01, repeated measures ANOVA). (C) (D) To confirm whether the memory impairments observed in the Tg2576 mice were attenuated by neuritin expression, a probe test was performed 24 h after the 5^th training day and the average latency without platform in zone 4, where the platform was placed during the training period, was recorded. The wt-EGFP, wt-neuritin and Tg2576-neuritin mice but not the Tg-EGFP mice spent significantly more time in zone 4 than in the other zones (zones 1, 2 and 3) (**p<0.01, two-way ANOVA followed by post hoc Bonferroni test).