Research Paper Volume 4, Issue 12 pp 966—977

Figure 4. Evidence for proliferation in cardiomyocytes. (A) Whole hearts and magnifications are shown for hearts LAD-ligated on P0.5 and harvested on P4.5. Sections were stained with H&E, immunoflourescently labeled for TroponinT and DAPI, and for the proliferation marker Ki67. Images are representative of 4 mice analyzed. Note the border zone of the infarction area (arrows) and the complete loss of TroponinT positive cardiomyocytes in the infarction zone (asterisk). (B) High magnification (63 fold) of a heart stained for TroponinT, phospho-Histone3 (Ser10, pH3), and DAPI after 4 days of LAD ligation (P0.5-P4.5). Note the double pH3 and TroponinT positive cardiomyocytes (arrows) at the border zone of the area of infarction (marked by X). (C) Whole hearts and magnifications are shown for hearts LAD-ligated on P0.5 and harvested on P7.5. Sections were stained using H&E and immunoflourescently labeled for TroponinT, DAPI, and BrdU as a marker for DNA replication. No residual TroponinT negative area is visible, indicating complete cardiac regeneration. Images are representative of 4 mice analyzed. (D) High magnification of a heart stained for TroponinT, BrdU, and DAPI after 7 days of LAD ligation (P0.5-P7.5). Arrows point at BrdU incoperation in TroponinT positive cardiomyocytes.