RT-qPCR revealed that compared with the NC group, significantly higher levels of Col1a, Col3a, MM2, MMP9, α-SMA, and TIMP1 mRNA transcripts were detected in heart tissues of DCM group, which were significantly reduced, except for Col3a, in the rats with IDO-OE hUCMSCs (Fig. 6F). The gene discussed is MMP9; the disease is familial dilated cardiomyopathy.