Objective: To investigate the differential expression profiles of microRNAs in the knockout Pax-8 mice by miRNA microarray analysis and study the function of microRNA during cardiac development.
Methods: The knockout Pax-8 mice model was established and the total RNA derived from Pax-8 KO-/- and Pax-8 KO+/- mice heart. MicroRNA microarray containing 567 mammalian microRNA probes was used to investigate the microRNAs differential expression between Pax-8 KO-/- and Pax-8 KO+/- mice. The candidates of microRNAs were confirmed by real time RT-PCR assay.
Results: The heart of pax-8 KO-/- mice became spheroidal. Left ventricle enlargement, left ventricular wall and interventricular septum thickening and papillary muscles in left ventricle enlargement were found. Furthermore, many apoptotic cells were discovered in left ventricular wall and interventricular septum in pax-8 KO-/- mice. The MicroRNA microarray result displayed 10 microRNAs differential expressions, in which 2 microRNAs became down-regulated and 8 microRNAs up-regulated by more than two folds in pax-8 KO-/- mice. This was in accordance with the result of real-time RT-PCR.
Conclusion: Some microRNAs may play important roles in cardiac development and ventricular septal defect pathogenesis.