Effects of maternal low-protein diet and spontaneous physical activity on the transcription of neurotrophic factors in the placenta and the brains of mothers and offspring rats.

Maternal protein restriction and physical activity can affect the interaction mother-placenta-fetus. This study quantified the gene expression of brain-derived neurotrophic factor (BDNF), neurothrophin 4, tyrosine kinase receptor B (TrkB/NTRK2), insulin-like growth factor (IGF-1), and insulin-like growth factor receptor (IGF-1r) in the different areas of mother's brain (hypothalamus, hippocampus, and cortex), placenta, and fetus' brain of rats. Female Wistar rats (n = 20) were housed in cages containing a running wheel for 4 weeks before gestation. According to the distance spontaneously traveled daily, rats were classified as inactive or active. During gestation, on continued access to the running wheel, active and inactive groups were randomized to receive normoprotein diet (18% protein) or a low-protein (LP) diet (8% protein). At day 20 of gestation, gene expression of neurotrophic factors was analyzed by quantitative polymerase chain reaction in different brain areas and the placenta. Dams submitted to a LP diet during gestation showed upregulation of IGF-1r and BDNF messenger RNA in the hypothalamus, IGF-1r and NTRK2 in the hippocampus, and BDNF, NTRK2, IGF-1 and IGF-1r in the cortex. In the placenta, there was a downregulation of IGF-1. In the brain of pups from mothers on LP diet, IGF-1r and NTRK2 were downregulated. Voluntary physical activity attenuated the effects of LP diet on IGF-1r in the hypothalamus, IGF-1r and NTRK2 in the hippocampus, IGF-1 in the placenta, and NTRK2 in the fetus' brain. In conclusion, both maternal protein restriction and spontaneous physical activity influence the gene expression of BDNF, NTRK2, IGF-1, and IGF-1r, with spontaneous physical activity being able to normalize in part the defects caused by protein restriction during pregnancy.

Maternal physical activity-induced adaptive transcriptional response in brain and placenta of mothers and rat offspring.

Maternal physical activity induces brain functional changes and neuroplasticity, leading to an improvement of cognitive functions, such as learning and memory in the offspring. This study investigated the effects of voluntary maternal physical activity on the gene expression of the neurotrophic factors (NTFs): BDNF, NTF4, NTRK2, IGF-1 and IGF-1r in the different areas of mother's brain, placenta and foetus brain of rats. Female Wistar rats (n = 15) were individually housed in voluntary physical activity cages, containing a running wheel, for 4 weeks (period of adaptation) before gestation. Rats were classified as inactive (I, n = 6); active (A, n = 4) and very active (VA, n = 5) according to daily distance spontaneously travelled. During gestation, the dams continued to have access to the running wheel. At the 20th day of gestation, gene expression of NTFs was analysed in different areas of mother's brain (cerebellum, hypothalamus, hippocampus and cortex), placenta and the offspring's brain. NTFs gene expression was evaluated using quantitative PCR. Very active mothers showed upregulation of IGF-1 mRNA in the cerebellum (36.8%) and NTF4 mRNA expression in the placenta (24.3%). In the cortex, there was a tendency of up-regulation of NTRK2 mRNA (p = 0.06) in the A and VA groups when compared to I group. There were no noticeable changes in the gene expression of NTFs in the offspring's brain. Our findings suggest the existence of a developmental plasticity induced by maternal physical activity in specific areas of the brain and placenta representing the first investment for offspring during development.

The mediation effect of anthropometry and physical fitness on the relationship between birthweight and basal metabolic rate in children.

BACKGROUND: Birthweight (BW) has been associated with anthropometry, body composition and physical fitness during growth and development of children. However, less is known about the mediation effect of those variables on the relationship between BW and basal metabolic rate (BMR) in children. OBJECTIVE: To analyse the mediation effect of anthropometry, body composition and physical fitness on the association between BW and BMR in children. METHODS: In total, 499 children (254 boys, 245 girls) aged 7-10 years were included. Anthropometry (weight, height, head, waist and hip circumferences), body composition (skinfolds thickness, body fat percentage), physical fitness (handgrip strength, flexibility, muscular endurance, muscular explosive power, agility, running speed) and BMR were evaluated. The analyses were conducted by: single-mediator analysis (SMA) and multi-mediator analysis (MMA). RESULTS: The SMA indicates height, head, waist and hip circumferences and handgrip strength as significant mediators of BW on BMR for boys and height, hip circumference and handgrip strength as significant mediators of BW on BMR for girls. In MMA for girls, there were significant indirect effects for height, hip circumference and handgrip strength, with 79.08% of percent mediation. For boys, the head and waist circumferences mediation had a significant indirect effect, with 83.37% of percent mediation. CONCLUSION: The anthropometric variables associated with BW were body height, head, hip and waist circumferences for boys and body height and hip circumference for girls. The current study provides new evidence that height and handgrip strength during childhood mediated the relationship between BW and BMR.