Figure 4

Figure 4

(A) MTT assay for cell proliferation in H9C2 cardiomyoblasts treated with 5 µg/mL CPP531 for 72 h. (B) Representative micrographs of the treated cardiomyoblasts. Scale bar = 200 μm. (C) BrdU labelling of rat neonatal cardiomyocyte nuclei after treatment with 5 µg/mL CPP531 5 µM BIO for 72 h. (D) RT-PCR analysis of p27^Kip1 and p57^Kip2 mRNA expression in rat neonatal cardiomyocytes after treatment with 5 µg/mL CPP531 or 5 μM BIO for 72 h. (E) Quantification of p27^Kip expression. (F) Effect of 5 µg/mL CPP531 on cardiomyocyte proliferation in Tg(cmlc2:GFP) transgenic zebrafish. 20 hpf larvae were treated with CPP531 until 48 hpf and EdU staining was carried out at 72 hpf. Heart tissue and neighboring yolk sac are designated with dashed lines. White arrows designate double-labelled, proliferating cardiomyocytes. Two representative fish from the CPP531 treated and untreated groups are shown. For (A): *p < 0.05 for significantly increased proliferation compared to vehicle treated cardiomyoblasts. For (C): *p < 0.05 for significantly increased BrdU labelling compared to vehicle treated cardiomyocytes. For (C): *p < 0.05 for significantly decreased expression compared to vehicle treated cardiomyocytes.