Myocardial proliferation/regeneration in rats with experimental acute myocardial infarction
10.3760/cma.j.issn.0253-3758.2013.11.012
- VernacularTitle:急性心肌梗死后心肌细胞增殖和再生的初步实验研究
- Author:
Zhan-Ling LIAO
1
;
Bing-Yin WANG
;
Feng LIU
Author Information
1. 215021,上海交通大学医学院苏州九龙医院心脏中心
- Keywords:
Myocardial infarction;
Rgeneration;
Cell proliferation
- From:
Chinese Journal of Cardiology
2013;41(11):950-954
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the myocardial proliferation/regeneration capacities at different time points and at different parts of the heart post acute myocardial infarction (AMI) in rats.Methods A total of 64 adult Sprague-Dawley (SD) rats were randomly divided into AMI group (left anterior descending coronary ligation,n =44) and sham-operated group (n =20).Rats were sacrificed on day 3,5,7,14 and 60 respectively post operation (n =5-9 at each time point) and ventricular tissues were harvested.5-Bromo-2-deoxyUridine (Brdu,50 mg/kg) was injected intraperitoneally at 12 and 24 hours before sacrifice.Morphological and pathological changes of the myocardium were observed after HE staining.Brdu-positive and c-kit and Brdu double-positive cardiomyocytes were analyzed post immunohistochemistry and immunofluorescence staining.Striated structure of new cells was detected by PTAH staining.Alpha-sarcomeric actin antibody was used to identify new cardiomyocytes.Result Brdupositive cardiomyocytes at border zone and non-ischemic zone were significantly increased at 5 days post AMI and peaked at 7th day post operation (Border zone,AMI:1.26％ ±0.15％ vs.Sham:0.22％ ±0.06％,P ＜0.01; right ventricle,AMI:0.75％ ± 0.12％ vs.Sham:0.18％ ±0.07％,P＜0.01).There was no significant difference between the two groups on the 60th post-operation day.Brdu-positive cells were 1.7-fold higher in infarct border zone than in the right ventricular area of AMI rats on the 7th post operation day (1.26％ ±0.15％,vs.0.75％ ±0.12％,P ＜0.01) and was 1.4-fold higher on the 14th post operation day (0.77％ ± 0.09％,vs.0.54％ ± 0.11％,P ＜ 0.01).PTAH staining evidenced myocardial striated structure inside the new cells.Immunofluorescent assay showed that parts of Brdu positive cells were myocardial actin positive,and the c-kit and Brdu double-positive myocardial cells were also observed.Most nuclei of tehse new cardiomyocytes were small and round-shaped.Conclusions Myocardial proliferation/regeneration increased significantly after AMI in rats,especially around the infarct border zone.The myocardial proliferation/ regeneration was time-dependent.Parts of the new cardiomyocytes had some characteristics of cardiac stem cells.This study suggests that myocardial proliferation/regeneration may be activated after acute myocardial injury.
