The effect of maternal hypothyroidism on microRNA expression profiles in the brain of rat offsprings / 中华内分泌代谢杂志

ABSTRACT

Objective To analyse the differential expression of miRNAs in the brain of offsprings of hypothyroid and normal rats,and to explore the molecular mechanism underlying the effect of hypothyroidism on brain development in the offspring.Methods Forty-eight female Wistar rats were assigned to (1) control group (n =24),and (2) hypothyroid group after complete thyroidectomy (n =24).Serum TSH and Total thyroxine (T4) were measured one month after the surgery.Brain samples of fetal or postnatal rats were obtained during four different developmental stagesembryonic days (E) 13,E17,postnatal days (P) 0 and P7.The hippocampus and cortex were separated on P7.MiRNAs were isolated from tissues and two samples were used at each time point studied to reduce the influence of individual differences.The brain samples were detected by Gene Chip miRNA arrays (Affymetrix).Results In the brain tissues of fetal or neonatal rats of maternal hypothyroid rats,two miRNAs (mir-206,-324-5p) on E13,three miRNAs (mir-34c,-204,-194) in cortex on P7,and five miRNAs (mir-146b,-532-5p,-384-5p,-215,-212) in hippocampus on P7 were up-regulated by over 2 folds.Five miRNAs (mir-200b,-200c,-217,-672,-139-5p) on E17,one miRNA (mir-376-3p) on P0,and four miRNA (mir-672,-204,-335,-376-3p) in hippocampus on P7 were decreased by 50％ or more.Conclusion The miRNA expression profiles in the rat brain of offspring with maternal hypothyroidism are characterized by miRNA arrays.The identification of a subset of brain expressed miRNAs in the brain may explain the brain development abnormalities resulting from maternal hypothyroidism.