Delay in the onset of puberty of intrauterine growth retarded female rats cannot be rescued by hypernutrition after birth
T. Matsuzaki, G. Gereltsetseg, T. Iwasa, R. Kinouchi, H. Nakazawa & M. Irahara
Perinatal undernutrition is known to disturb reproductive development, in particular by delaying the onset of puberty in certain species. Using a rat model, we studied whether hypernutrition after birth can rescue the delayed onset of puberty in intrauterine undernourished female rats. Pregnant rats were divided into two groups the maternal normal nutrition (mNN, n=8) and maternal undernutrition (mUN, n=9) groups. In the mUN group, dams received 50% of the daily food intake of the mNN group from day 15 of pregnancy until delivery. Pups from both the mNN and mUN dams were then separated into two groups, based on their postnatal feeding
Conditions: control-normal nutrition (control-NN), control-hypernutrition (control-HN), IUGR-normal nutrition (IUGR-NN), and IUGR-hypernutrition (IUGR-HN). Litter sizes of the hypernutrition groups were controlled to five pups per dam, and normal nutrition groups to 1213 pups per dam. From postnatal day 30, pups were inspected daily for vaginal opening (VO). The age of VO in the IUGR-NN group was 35.7±2.4 days (mean ± S.D.), which was significantly delayed compared to that of the control-NN group (33.8±0.8 days). The age of VO in the IUGR-HN group was 35.5±2.3 days, which was significantly delayed compared to that of the control-HN group (33.5±0.8 days). Interestingly, the age of VO did not differ between the IUGR-NN and IUGR-HN groups. In conclusion, maternal undernutrition delays puberty in female offspring, and this delay in puberty cannot be rescued with hypernutrition after birth.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.