NOX2 inhibition prevents obesity-mediated atrial fibrosis and increases atrial CV. To study changes in conduction, epicardial multielectrode array mapping of both atria and the left ventricle was performed in isolated Langendorff-perfused beating hearts from all 4 mouse groups. The CVs were reduced in both atria and the left ventricle in DIO, Nox2-KO, and DIO Nox2-KO mice compared with controls. However, DIO Nox2-KO mice showed improved LA and RA and left ventricular CV compared with DIO mice (Figure 5, A–D). The isochronal maps also illustrated a pattern consistent with improved CV in both atria of DIO Nox2-KO mice compared with DIO mice (Figure 5, A–D). We then determined whether NOX2 inhibition reduces obesity-induced atrial fibrosis by using Picrosirius red and Masson’s trichrome staining on histological sections from control, DIO, and DIO Nox2-KO mice.

Figure 5. NOX2 inhibition prevents atrial fibrosis and increases atrial CV in DIO mice. (A) Representative isochronal maps of the LA in the 3 groups of mice using electrical mapping. (B) Quantification of mean LA CV in control (n = 6), DIO (n = 6), Nox2-KO (n = 5), and DIO Nox2-KO mice (n = 6). (C) Representative isochronal maps of the RA in the 3 groups of mice using electrical mapping. (D) Quantification of mean RA CV in control (n = 6), DIO (n = 6), Nox2-KO (n = 5), and DIO Nox2-KO mice (n = 6).

The Journal of Clinical Investigation

https://doi.org/10.1172/JCI175447