AAS ›› 2015, Vol. 46 ›› Issue (6): 824-831.doi: 10.16098/j.issn.0529-1356.2015.06.017

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Cardiomyocyte spontaneous regeneration following isoproterenol-induced left ventricular injury in rats

CAI Xin-hua 1* CAI Qing-hui2 ZHANG Yong-chun3 TIAN Xiang-qin 1   

  1. 1. Key Laboratory for Tissue Regeneration of Henan Province, Xinxiang Medical University, He’nan Xinxiang 453003, China;2. Intensive Care Unit, Zhengzhou Seventh People’s Hospital, Zhenzhou 450000, China; 3. Department of Cardiology, the First Affiliated Hospital, Xinxiang Medical University, He’nan Xinxiang 453100, China

  • Received:2015-04-21 Revised:2015-06-20 Online:2015-12-06 Published:2015-12-06
  • Contact: CAI Xin-hua E-mail:861003@xxmu.edu.cn

Abstract:

Objective The notion of the adult heart as a terminally differentiated organ without the potential for self-renewal has been undermined by the identification of a subpopulation of proliferating cardiomyocytes in both the healthy and pathological states. Our purpose is to determine whether the expression of stem cell markers was associated with the spontaneous regeneration of cardiomyocytes in rats following isoproterenol hydrochloride (ISO)-induced cardiac necrosis.
Methods Rats (n=40) were injected subcutaneously with 4 mg/(kg.d) ISO for 7 days. The morphological structures were observed, the expression of stem cell and caridomyocyte markers were detected, and the characteristics of proliferation cell were surveyed in the necrotic area utilizing morphology, immunofluorescene and EdU labeling technology. Results The histopathological examination showed that the ischemic necrosis was limited to the area of the myocardium near the endocardium. A small number of round or ellipsoid and rod-shaped cells with strongly stained acidophilic cytoplasm were dispersed throughout the necrotic LV tissue. The ultrastructure analyses showed that the rod-shaped cells had the features similar to those of naive cardiomyocytes. The immunofluorescent staining showed that c-kit+/gata+ cells, nanog+ cells, CD34+/gata+ cells and CD34+/factor Ⅷ+ cells were present in the necrotic tissue. The EdU labeling showed that the cTnI+ cells in the necrotic area were actively proliferating cardiomyocytes. Conclusion Cardiac stem cells expressing c-kit, nanog, or CD34 participate in the spontaneous regeneration of necrotic area caused by ISO. The naive cardiomyocytes are formed in necrotic area. The CD34+ stem cells participate in the repair of the micro-vessel in the necrotic area of the myocardium.

Key words: Cardiac regeneration, Stem cell marker, Cardiomyocyte marker, Isoproterenol hydrochloride, EdU labeling, Immunofluorescence, Rat