Fig. 2

Effect of chronic oral P021 treatment on behavior in Cdkl5 KO mice. A Experimental protocol. Starting from postnatal day 21 (P21), Cdkl5 − /Y mice were orally treated with the P021 diet, containing 60 nmol peptide/g formulated diet, for 70 days. As a control Cdkl5 − /Y and Cdkl5 + /Y mice were administered with the same diet but without P021. Animals from different experimental groups received a single intraperitoneal (i.p.) injection (150 μg/g body weight) of BrdU at P70 and were behaviorally tested starting from P74 to P89. Animals were sacrificed the day after completion of the behavioral task (P90). B Body weight in grams of vehicle-treated (+ /Y n = 9, − /Y n = 7) and P021-treated (− /Y + P021 n = 6) Cdkl5 male mice over the whole treatment period. C, D Autistic-like features in treated Cdkl5 − /Y mice. Number of marbles buried (C) and nest quality (D) of vehicle-treated Cdkl5 + /Y and − /Y mice and of P021-treated Cdkl5 − /Y mice as in B. E Total amount of time spent hind-limb clasping during a 2-min interval in vehicle-treated Cdkl5 + /Y and − /Y mice and in P021-treated Cdkl5 − /Y mice as in B. F Frequency of passive rotations on the accelerating rotating rod in vehicle-treated Cdkl5 + /Y (n = 8) and − /Y (n = 7) mice and in P021-treated Cdkl5 − /Y mice (n = 6). G Amount of time taken to remove both paws from the bar in vehicle-treated Cdkl5 + /Y and − /Y mice and in P021-treated Cdkl5 − /Y mice as in B. H, I Total amount of time spent in the center (H), and along the walls (I) of the open field arena during the 20-min trial in vehicle-treated Cdkl5 + /Y and − /Y mice and in P021-treated Cdkl5 − /Y mice as in B. J Spatial learning (5-day learning period) assessed using the Morris water maze in vehicle-treated Cdkl5 + /Y and − /Y mice and in P021-treated Cdkl5 − /Y mice as in B. K Spatial memory on day 6 (probe test). Memory was assessed by evaluating the latency to enter the former platform zone. L, M Latency of entrance into the dark compartment of the passive avoidance apparatus during the training day (L) and the probe day (M) of the test in vehicle-treated Cdkl5 + /Y (n = 9) and − /Y (n = 7) mice and in P021-treated Cdkl5 − /Y mice (n = 6). Values are represented as means ± SEM. * p < 0.05, ** p < 0.01, *** p < 0.001. Fisher’s LSD test after one-way ANOVA for data set in (C-I, K-M) and after two-way RM ANOVA for data set in (B, J)