Effect of calcitonin gene-related peptide on recruitment of cardiac stem cells and cardiac functions after acute myocardial infarction in rats

AIM To observe the effect of calcitonin gene-related peptide (CGRP) on cardiac stem cell recruitment and cardiac function after acute myocardial infarction (AMI) in rats. METHODS AMI rat model was established by left anterior descending artery ligation. Rats were randomly divided into sham-operated group (n=30), control group (n=30) and CGRP group (n=30). Phosphate-buffered saline (PBS) in control group or CGRP in CGRP group was injected into rat cardiac tissues after MI. Animals were sacrificed at 3 days, 7 days, 14 days and 28 days. Recruitment of cardiac stem cells (CSCs) was observed by immunofluorescence staining, cardiac morphological changes were observed by HE, Masson and TTC staining, and cardiac functions were assessed using echocardiography. RESULTS The number of CSCs increased on day 3, reached the peak on day 7 and decreased significantly on day 14 in both control group and CGRP group. CSCs significantly increased in control group at each time point compared with those in sham-operated group (P<0.05). CSCs in CGRP group were more obviously increased compared with those in control group (P<0.05). At 28 days after operation, cardiac function indexes were significantly improved, whereas collagen fibers and infarct area were significantly reduced in CGRP group compared with those in the control group (both P<0.05). CONCLUSION CGRP could promote CSC recruitment in the infarcted zone, which reaches the peak on day 7. GGRS improves cardiac functions after AMI.