Fig. 4: p22^phox cKO mice showed abnormal Ca²⁺ handling.

a–f, Ca²⁺ transient and SR Ca²⁺ content in p22^phox cKO myocytes at baseline and after 1-week TAC. Adult cardiomyocytes were isolated from control and p22^phox cKO mice using the Langendorff perfusion method. The cardiomyocytes were loaded with Fluo-4 AM. Ca²⁺ fluorescence intensity was recorded as the ratio of the fluorescence (F) over the basal diastolic fluorescence (F₀). a, Twitch Ca²⁺ transient and SR Ca²⁺ content measured as the height of the caffeine (10 mM)-induced Ca²⁺ transient in representative ventricular myocytes from control and p22^phox cKO mice at baseline and 1 week after TAC. Ca²⁺ fluorescence intensity was recorded as the ratio F/F₀ of the fluorescence (F) over the basal diastolic fluorescence (F₀). b–f, Summarized data for twitch representing the mean ± s.e. from three mice per condition and specified number of cells per mouse Ca²⁺ transient amplitude (WT: sham—6, 6, 9, TAC—7, 9, 9; p22^phox cKO: sham—8, 8, 8, TAC—8, 7, 7) (b), SR Ca²⁺ content (WT: sham—7, 7, 8, TAC—7, 7, 10; p22^phox cKO: sham—7, 7, 8, TAC—7, 7, 8) (c), fractional SR Ca²⁺ release (WT: sham—7, 7, 8, TAC—7, 7, 10; p22^phox cKO: sham—7, 7, 8, TAC—7, 7, 8) (d), decay constant (tau) (WT: sham—6, 6, 7, TAC—7, 9, 11; p22^phox cKO: sham—8, 7, 7, TAC—6, 6, 10) (e) and caffeine peak decay constant (tau) (WT: sham—8, 8, 8, TAC—8, 6, 10; p22^phox cKO: sham—8, 3, 9, TAC—8, 6, 10) (f) in control and p22^phox cKO ventricular myocytes at baseline and after 1-week TAC. The individual data points from cells of each mouse are represented by dots (filled black and blue dots and black empty dots). The statistical analysis was conducted using the nested t-test (two tailed) (c and f), nested one-way ANOVA and Tukey’s multiple-comparison test (b and e), and nested one-way ANOVA and Šidák’s multiple-comparison test (d). Hierarchical clustering dendrogram analysis was performed, and the dendrogram is provided in the source data.

Source data