Effects of maternal undernutrition on lung growth and insulin-like growth factor system expression in rat offspring

Background: Maternal undernutrition may alter the development of the lung structure in rat offspring. Methods: We investigated the effects of maternal undernutrition (50% rations of the control food intake) during the last week of gestation on the expression of the rat lung insulin-like growth factor (IGF) system in the postnatal period. Results: Body weights of undernourished pregnant rats were significantly lower than those of control rats from gestational days 16 to 21. Rats subjected to intrauterine growth restriction (IUGR) exhibited significantly lower body weights and lower lung weights on postnatal days 1, 7, 14, and 28 and lower lung/body weight ratios on postnatal days 7 and 14 when compared with control rats. Lung IGF-I, IGF-II, IGF receptors types 1 (IGFR-1) and 2 (IGFR-2), and the IGF binding protein (IGFBP) mRNA expressions increased as rats aged and reached a peak on postnatal day 14. Maternal undernutrition significantly increased IGF-I and IGF-II mRNA expressions on postnatal days 1 and 28. Lung IGFR-1, IGFR-2, and IGFBP mRNA expressions were similar between control and IUGR rats during the study period. Conclusions: This study presents a comprehensive overview of lung IGF system expression in control and IUGR rats and demonstrates the developmental regulation of each component.