Fig. 4.

7,8-DHF treatment improves baseline breathing stability in 6-wk-old Mecp2 mutant mice. A: representative plethysmography traces from a single mouse within each group showing the highly irregular breathing pattern in the MT0 group compared with the regular breathing patterns in the WT0 and WT80 groups and the partial rescue of this irregularity in the MT80 group. The small dots indicate an accepted breath. B: scatterplots of T_TOT from 100 continuous respiratory cycles of 3 representative mice from each group, showing the high variability in the MT0 group and reduced variability in the MT80 group compared with the WT0 and WT80 groups. C: bar graphs of T_TOT ± 95% confidence interval (CI) and coefficient of variation (CV) in each group. Open white bars: WT0 (n = 12). Open shaded bars: WT80 (n = 8); hatched white bars: MT0 (n = 9); hatched gray bars: MT80 (n = 6). T_TOT was significantly increased in the MT0 group compared with all other groups (WT0: P < 0.001, WT80: P = 0.014, and MT80: P = 0.038) and T_TOT in the MT80 groups was not significantly different from the WT0 (P = 0.080) or WT80 (P = 0.349) groups. Similarly, the CV and CI was significantly greater in the MT0 vs. all other groups (all P < 0.05). The CV of MT80 remained significantly higher than the WT0 and WT80 groups (both P < 0.001). These data suggest that the untreated Mecp2 mutants had highly variable breathing patterns that were partially (but not completely) restored by treatment with 7,8-DHF. *P < 0.05 vs. WT0, WT80 and MT80 groups. #P < 0.05 vs. WT0 and WT80 groups. T_TOT data presented as means ± 95% CI, whereas CV data presented as means + SE.