Effect of overnight IH on whole blood DUSP1 mRNA from control and OSA subjects. (A) Graphical representation of whole blood DUSP1 mRNA before sleep (9:00 pm), after sleep (6:00 am) and during day (11:00 am) in healthy controls (white bars; n=8) and OSA subjects (black bars; n=8). Increased DUSP1 mRNA was seen in OSA subjects at 6:00 am after a night of IH episodes (*is P≤ 0.05, 6:00 am vs. 9:00 pm OSA group; $ is P≤ 0.05, 6:00 am control vs. OSA group). DUSP1 mRNA showed no differences over the three time points in the control group. (B) Increases in early morning DUSP1 mRNA in OSA subjects is attenuated by nCPAP treatment. The black bars represent OSA subjects without nCPAP (n=4) and the grey bars represent OSA subjects with nCPAP treatment (n=4). No change in DUSP1 mRNA was observed in OSA subjects with nCPAP treatment in all three time points whereas patients naïve to treatment were characterized by evident DUSP1 mRNA increases at 6:00 am (*is P≤0.05, 6:00 am vs. 9:00 pm OSA group without nCPAP treatment; $ is P≤0.05, 6:00 am OSA group with vs. without nCPAP treatment). Data are presented as mean ± SD. Statistical significance was determined by unpaired student t-test for direct comparisons between groups, and ANOVA with repeated measurements for time-related assessment.