As depicted in Figure 4(a) and Table 1, there was no difference in the heart rate of mice in each group, and there was an obvious reduction in cardiac systolic function as reflected by EF% and FS% after 5/6 Nx in mice, while it was improved in the CCN1−/− or CCN1−/− + CKD group. This evidence concerns the gene CCN1 and chronic kidney disease.