The expression profile of microRNAs in wistar rats with lipopolysaccharide-induced periventricular leukomalacia.

Over the recent decades, with numbers of premature infants being cured, clinical diseases on brain damage like periventricular leukomalacia (PVL) have become much more common. Meanwhile, since the discovery of first miRNA lin-4, an increasing number of important studies about this small RNA have been performed not only in the normal organ development but also in the pathogenic mechanism of diseases. However, throughout the past several years, there have been rare miRNA researches discussing the connection between the PVL and miRNA. In view of this situation, we constructed an animal model of PVL induced by lipopolysaccharide (LPS) and performed a miRNA microarray which was repeated three times to profile the expression of microRNAs (miRNAs) between two groups (PVL group versus control group). Then, miRNAs with notable fold changes (fold change >1.5) were found; some of them were further validated by real-time PCR. As a result, 104 differentially expressed miRNAs were identified using the microarray, including 64 upregulated and 40 downregulated miRNAs. Then, five miRNAs of them were selected, characterized by consistent trend in expression in all three microarrays. Among these five miRNAs (miRNA-451, miRNA-200b, miRNA-29a, miRNA-21, and miRNA-138), we subsequently selected miRNA-451 and miRNA-200b for real-time PCR because they possess the highest fold changes. Finally, the results of PCR are basically in accord with the microarray. We guess these new identified miRNAs may play an important role in the pathogenesis of PVL and may provide certain pathophysiological basis for the future research of related diseases in preterm infants.