Objective    To observe the differential expression of microRNAs in decidua of spontaneous abortion mice (CBA/J×DBA/2) and normal pregnant mice (CBA/J×BALB/c).     Methods    A spontaneous abortion mouse model and a normal pregnant mouse model were established. Expression of miRNAs in decidua of the two models was detected by miRCURY LNA

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microRNA array 10.0. Differential expression of microRNAs was detected by function analysis and prediction of target genes.     Results    The embryo resorption rate was significantly higher in the CBA/J×DBA/2 group than in the CBA/J×BALB/c group (30.9% vs 7.0%，P0.01). The data

on microRNA chip showed that the expression of 13 miRNAs，including up-regulated and down-regulated expression of 8 and 5 miRNAs (ratios≥2.0 or≤0.5) was significantly different in decidual tissue of spontaneous abortion and normal pregnant mice. The prediction software showed that the target genes of miR-26a and miR-21 were LIF and RECK.     Conclusion    Differential expression of miR-26a and miR-21 in decidua may play an important role in spontaneous abortion of mice.