Transcriptome analysis of postnatal mouse cardiac tissue growth and development.

Postnatal cardiac function in mammals is closely associated with cardiomyocyte proliferation and hypertrophy. However, the molecular mechanisms regulating cardiomyocyte proliferation and hypertrophy have not yet been fully elucidated. Therefore, phenotypic measurements and transcriptomic sequencing were performed on myocardial tissues from 7-day-old (P7) and 3-month-old (3m) female C57BL/6 mice to investigate changes in cardiomyocytes during growth and development and to identify key genes regulating myocardial growth and development. In comparison to 7-day-old mice, 3-month-old mice exhibited a significant increase in heart weight (P<0.001) and the cross-sectional area of cardiomyocytes (P<0.001). Transcriptome sequencing identified 3,858 differentially expressed genes (DEGs), including 2,021 up-regulated and 1,837 down-regulated genes. Gene Ontology (GO) functional annotation analysis demonstrated that the differentially expressed genes were significantly enriched in biological processes including cell cycle, cell division, cardiac morphogenesis and cellular proliferation. Significantly enriched KEGG pathways were identified, including those for DNA replication, ECM-receptor interaction, the cell cycle, metabolic pathways, and other signaling pathways. Furthermore, key candidate genes associated with myocardial tissue growth and development in mice, including Hey2, Foxm1, Igf1, Xirp2, Sfrp2, Egf, Fgfr2, Tbx20, Fgf1 and Igf2 were identified through screening. qRT-PCR validation results demonstrated that the expression trends of the 10 candidate genes related to myocardial growth and development were consistent with the RNA-seq results, confirming the reliability of the sequencing data. The findings of this study provide new insights into the molecular mechanisms underlying the growth and development of mouse myocardial tissue.