Different effects of maternal parity, cold exposure and nutrient restriction in late pregnancy on the abundance of mitochondrial proteins in the kidney, liver and lung of postnatal sheep.

Adaptation to the extrauterine environment at birth relies upon the onset of postnatal function and increased metabolism in the lungs, liver and kidney, mediated partly by activation of mitochondrial proteins such as the voltage-dependent anion channel (VDAC), cytochrome c and, in the lung only, uncoupling protein (UCP)2. The magnitude of adaptation is dependent on the maternal metabolic and endocrine environment. We, therefore, examined the influence of maternal cold exposure (MCE) induced by winter shearing of pregnant sheep in conjunction with nutrient restriction (NR; 50% reduction in maternal food intake from 110 days gestation up to term). The effect of parity was also examined, as the offspring of nulliparous mothers are growth restricted compared with multiparous offspring. All sheep were twin bearing. One twin was sampled after birth and its sibling at 30 days. In the lung, both MCE and maternal nulliparity enhanced UCP2 abundance. However, whilst VDAC abundance was decreased in both the offspring of nulliparous mothers and by NR, it was transiently raised by MCE. Kidney VDAC abundance was reduced by MCE and nulliparity, adaptations only influenced by NR in multiparous mothers. Cytochrome c abundance was raised by MCE and by NR in multiparous controls and raised in offspring of nulliparous mothers. Liver VDAC and cytochrome c abundance were transiently reduced by MCE and persistently lower in offspring of nulliparous mothers. In conclusion, changes in the maternal metabolic environment have marked tissue-specific effects on mitochondrial protein abundance in the lungs, liver and kidney that may be important in enabling the newborn to effectively adapt to the extrauterine environment.