Th17/Tregs imbalance regulates cardiac fibrosis and heart failure in rats by regulating lysyl oxidase (LOX) expression, Th17 cells aggravate fibrosis-related indicators (matrix metalloproteinase-2/matrix metalloproteinase-9 (MMP-2/9) and collagen I/III) and LOX expression by activating the IL-17/ERK1/2-activating protein-1 (AP-1) pathway, while Tregs inhibit fibrosis-related indicators and LOX expression by activating the IL-10/Janus kinase (JAK) 1-signal transducer and activator of transcription (STAT)3 pathway (77). This evidence concerns the gene MMP2 and heart failure.