Active and total TGF-β levels in sham and two weeks post-myocardial infarction (MI) mice left ventricular myocardium measured by ELISA and bioassay. A: Active TGF-β levels and B: Total TGF-β levels in sham and two weeks post-MI heart homogenate. For both sham and MI, bioassay revealed not only significantly higher TGF-β levels than ELISA (p < 0.05), but also showed significant increase of both TGF-β levels in MI compared with sham (p < 0.05), whereas ELISA failed to show significant increase in MI compared with sham. Sample size: n = 6. ELISA=enzyme-linked immunosorbent assay, MI=myocardial infarction, TGF-β=transforming growth factor-β.