A cardiac fibrosis model was established by treating CFs (P5) in the microdevices with 10 ng/mL TGF-β1 for 24 hours prior to compression stimulation, the first group receiving only mechanical stimulation, labeled M; the second group continuously treated with TGF-β inhibiting drug, Tranilast, and mechanical stimulation, labeled DM; the third group continuously treated with TGF-β1 and mechanical stimulation for 7 days, labeled TM; and the last group without any mechanical compression or TGF-β1 treatment, labeled C. (a) Representative confocal images of immunofluorescence stained α-SMA (green) and collagen-I (Col I, red) after 7 days cyclic compression stimulation with different strains from 0 to 20% (n=4). (b) RT-PCR of relative mRNA expression of α-SMA, Col-I, Fnand MMP-2 ofCFsafter 7 days cyclic compression stimulation of different strain from 0 to 20% (n=4). Data depicts fold-change ± standard deviation. *p<0.05,** p<0.01, *** p<0.001.