The line graphs (Panels A, B, C, and D) show diastolic stress over sarcomere lengths in different conditions: male-ctrl, male HFpEF-like, female-ctrl, and female HFpEF-like, respectively. The x-axis represents sarcomere length in micrometers, ranging from 1.8 to 2.2 micrometers. The y-axis represents diastolic stress in millinewtons per square millimeter, ranging from 0 to 8.0 millinewtons per square millimeter. Each graph compares diastolic stress before and after treatment with the crossbridge inhibitor BDM, with the gray area indicating the extent of crossbridge contribution. Panel A shows data for male-ctrl, Panel B for male HFpEF-like, Panel C for female-ctrl, and Panel D for female HFpEF-like. The box plot (Panel E) summarizes the contributions of crossbridge and non-crossbridge stress at a sarcomere length of 2.15 micrometers. The x-axis labels indicate sex and heart condition: male and female with and without HFpEF-like condition. The y-axis represents stress in millinewtons per square millimeter, ranging from 0 to 8.0 millinewtons per square millimeter. The box plot shows the median, interquartile range, and significant differences between groups, with p-values indicating statistical significance. The legend distinguishes between crossbridge stress (hatched bars) and non-crossbridge stress (solid bars) along with a table showing a linear mixed model for XB and Non-XB.
Diastolic XBs contribute to diastolic stress in intact cardiomyocytes. (A–D) Show diastolic stress over SLs in male-ctrl, male HFpEF-like, female-ctrl, and female HFpEF-like, respectively. The difference in diastolic stress measured before and after treatment with the XB inhibitor BDM (gray area) represents the extent of XB contribution. (E) The contributions of XB and non-XB stress at SL of 2.15 µm are summarized in E, and the significance of main effects (sex and heart condition) is shown. The data are presented as means ± SE. The sample sizes are 11, 13, 10, and 12 mice for male-ctrl, male HFpEF-like, female-ctrl, and female HFpEF-like, with 2–4 cells analyzed per mouse. Analysis was performed using a linear mixed model with least significant difference post-hoc comparisons. ns indicates not significant. For simplicity, post-hoc comparisons between male-ctrl vs. female HFpEF-like and male HFpEF-like vs. female-ctrl are not shown.