Collagen volume fraction (%), a marker of fibrosis, in control rat hearts and those hearts obtained from ALDO-, ALDO + Spi-, ALDO + PDTC-, and ALDO + NAC-treated rats. Compared to controls, collagen volume fraction was markedly increased in the right and left ventricles of ALDO-treated rats, which was prevented by co-treatment with either Spi, PDTC, or NAC. *, P < 0.01 compared to controls; †, P < 0.01 compared to ALDO-treated rats.