Intrauterine growth restriction promotes hypothalamic circadian dysregulation in adult mouse offspring.

Abstract

Adverse prenatal conditions can induce intrauterine growth restriction (IUGR) and increase the risk of adulthood metabolic disease. Mechanisms underlying developmentally programmed metabolic disease remain unclear but may involve disrupted postnatal circadian rhythms and kisspeptin signalling. We investigated the impact of maternal hypoxia-induced IUGR on hypothalamic and hepatic expression of clock genes (Bmal1, Per2 and Reverbα), metabolic genes (Pparα, Pparγ and Pgc1α) and kisspeptin genes (Kiss1 and Kiss1r) in adult offspring. Pregnant BALB/c mice were housed in hypoxic conditions (10.5% oxygen) from gestational day 11 to 17.5 and then returned to normoxic conditions until term (gestational day ∼ 21). Control animals were housed in normoxic conditions throughout pregnancy. Offspring were weighed at birth. At 8 weeks of age, body, liver and brain tissues were collected and weighed. Relative clock gene, metabolic gene and kisspeptin signalling gene expression were measured using qPCR. The IUGR offspring were lighter at birth and remained lighter at 8 weeks but with higher brain relative to body weight. The IUGR offspring had decreased hypothalamic Bmal1 and Reverbα expression, but unchanged hepatic clock gene expression and no change in hypothalamic or hepatic Per2 expression, compared with Control offspring. This tissue-specific change in clock gene expression suggests circadian dysregulation. There were no IUGR-related changes to metabolic gene expression in the hypothalamus or liver, but IUGR offspring had increased hypothalamic Kiss1r expression. These results demonstrate IUGR offspring from hypoxia pregnancies show central circadian misalignment and potentially disrupted hypothalamic Kiss1/Kiss1r signalling, which may contribute to developmentally programmed metabolic disease.