[Abnormal expression of microRNAs in the hippocampus of Ts65Dn mice].

Objective: To identify the differentially expressed microRNAs in the hippocampus of Down Syndrome model mouse Ts65Dn.

Methods: Low molecular weight RNA from hippocampus were tailed and reverse transcribed by extended RT-primer. MicroRNAs primers were arrayed on plates according to the Tm of each primer. PCR were carried out at different annealing temperatures using a gradient real-time PCR instrument. The relative expression level of each microRNAs was calculated using the most stable reference gene as normalizer which was selected by geNorm and Normfinder software.

Results: miR-27a was identified as the most stable reference gene by geNorm and Normfinder software. Among the 52 microRNAs detected by real-time PCR array, miR-33 and miR-19a were significantly down-regulated, whereas miR-130 were significantly up-regulated in the hippocampus of Ts65Dn mice as compared with the euploid control mice. The expression of miR-802, which was the trisomy chromosome 16 derived microRNAs, was very low in hippocampus with no difference between the two groups.

Conclusion: MicroRNAs are dysregulated in the hippocampus of Ts65Dn mice, which may contribute to the reduced neurogenesis of Down syndrome.