Ito Kohei, Morioka Mai, Kimura Shun, Tasaki Mai, Inohaya Keiji, Kudo Akira
Department of Biological Information, Tokyo Institute of Technology, Yokohama, Japan.
Dev Dyn. 2014 Sep;243(9):1106-15. doi: 10.1002/dvdy.24154. Epub 2014 Jun 25.
Zebrafish have the ability for heart regeneration. However, another teleost animal model, the medaka, had not yet been investigated for this capacity.
Compared with zebrafish, the medaka heart responded differently to an injury: An excessive fibrotic response occurred in the medaka heart, and existing cardiomyocytes or cardiac progenitor cells remained dormant, resulting in no numerical difference between the uncut and injured heart with respect to the number of EdU-incorporated cardiomyocytes. The results obtained from the analysis of the medaka raldh2-GFP transgenic line showed a lack of raldh2 expression in the endocardium. Regarding periostin expression, the localization of medaka periostin-b, a marker of fibrillogenesis, in the medaka heart remained at the wound site at 30 dpa; whereas zebrafish periostin-b was no longer localized at the wound but was detected in the epicardium at that time.
Compared with zebrafish heart regeneration, the medaka heart phenotypes suggest the possibility that the medaka could hardly regenerate its heart tissue or that these phenotypes for heart regeneration showed a delay.
斑马鱼具有心脏再生能力。然而，另一种硬骨鱼动物模型——青鳉，尚未针对这种能力进行研究。
与斑马鱼相比，青鳉心脏对损伤的反应不同：青鳉心脏出现过度纤维化反应，现存的心肌细胞或心脏祖细胞保持休眠状态，导致在EdU掺入的心肌细胞数量方面，未切割心脏与损伤心脏之间没有数值差异。对青鳉raldh2 - GFP转基因品系的分析结果显示，心内膜中raldh2表达缺失。关于骨膜蛋白的表达，青鳉骨膜蛋白 - b（一种原纤维形成标志物）在青鳉心脏中的定位在损伤后30天仍位于伤口部位；而斑马鱼骨膜蛋白 - b此时不再定位于伤口，而是在心脏外膜中被检测到。
与斑马鱼心脏再生相比，青鳉心脏表型表明青鳉几乎无法再生其心脏组织，或者这些心脏再生表型出现延迟。
