RESUMEN
Objective To observe the expression changes in microRNA (miR)-379 in the developmental process of the mouse heart and during the differentiation of P19 cells into cardiac myocytes,and to explore the possible relationship between miR-379 and the differentiation of cardiacmyocytes.Methods Heart tissues were collected from fetal mice in pregnant ones at their gestational age (8.5,11.5,14.5 and 18.5 days) respectively.Heart tissue sections of the fatal mice were obtained to observe the heart development process.Then total RNA was isolated from heart tissues by using the TRIzol method.Complementary DNA was synthesized from 1 μg total RNA by using a Reverse Transcriptase Kit.Finally,real-time PCR (RT-PCR) was employed to detect the expression of miR-379.At the same time,P19 cells were cultured with 10 mL/L Dimethyl sulfoxide in suspension for 4 days to form cell aggregation,and these aggregations were transferred into 6-wells plate for culturing by adherence.Beating cells were detected with microscopy on the 10th day after induction.Afterwards,total RNA was extracted from cultured P19 cells at different time points.Reverse transcription was executed to get DNA.At last,RT-PCR was used to explore the expression of miR-379 on 0,4,6,10 days after aggregation.Results The expression level of miR-379 was down-regulated gradually in the developing heart (at gestational age of 8.5,11.5,14.5,16.5 days,respectively),and there were significant differences on the different days (F =21.13,P ＜ 0.05).On the other hand,myocardial markers of troponin T represented an increasing trend during the process of P19 cells induction,which demonstrated that P19 cells were successfully induced into cardiomyocyte-like cells.Meanwhile,miR-379 showed a low expression on day 0 of P19 cells aggregation.On day 4,miR-379 demonstrated a higher level.Afterwards,miR-379 proved to be down-regulated gradually.Conclusions miR-379 plays a role in the process of the heart development,but the specific mechanisms need further research.