NRVMs were treated with DOX (2 μM) for 24, 48, and 72 h. a Representative western blot of PRMT4 was shown; b Quantitative analysis of the protein level of PRMT4. *P < 0.05, #P < 0.01, $P < 0.001; c The mRNA level of PRMT4 was determined; d Representative western blot of PRMT4 in the myocardium 7 days after DOX (15 mg/kg) injection; e Quantitative analysis of the protein level of PRMT4 in DOX-treated hearts. *P < 0.001; NRVMs were infected with adenovirus (Ad-NC, Ad-PRMT4, Ad-shNC, or Ad-shPRMT4) and treated with DOX (2 μM) for 24 h, f–i Adenovirus-mediated PRMT4 overexpression or depletion in vitro was detected by western blot and quantitatively analyzed; Representative images were shown; j, l Cell viability was detected. *P < 0.001, #P < 0.01 (j). *P < 0.001, #P < 0.001 (l); k, m TUNEL positive cells were determined. *P < 0.001, #P < 0.05 (k). *P < 0.001, #P < 0.05 (m). ns, not significant.