Effects Of Dehydration In Late Gestation On Development And Imprinting In The Brain RAS

PART 1 Effects of maternal water deprivation during late gestation on development of fetus and fetal brain RASObjective: To determine the fetal development and brain RAS affected by water deprivation at late term.Methods: After three days of maternal water deprivaton, fetal body, brain, placental were weighted, and fetal blood gases and electrolytes were determined with a Nova analyzer, plasma osmolality was determined with an advanced digmatic osmometer. The fetal brain blood flow was detected by a Laser Doppler. Protein and mRNA of Angâ…¡receptors (ATR) in the fetal brain were determined with western-blot or real-time PCR, and ATG mRNA in the fetal brain was also determined.Results: Prenatal exposure to WD at late term significantly decreased weight of the fetal body, brain, and increased fetal plasma Na+, hematocrit and osmolality. Fetal brain ATG mRNA was increased following WD. Maternal WD during late gestation altered the expression of both protein and mRNA of ATR in the fetal brain. Fetal brain blood flow was reduced.Conclusion: Three days of maternal WD during late gestation significantly changed the fetal RAS components, and affected the development of fetus.PART 2 Effects of maternal WD during late gestation on the brain RAS in the offspringObjective: To investigate the impact on the brain RAS and the body homeostasis in the adult offspring following maternal dehydration during late gestationMethods: The offspring in both the control and WD groups were used. The adult offspring body and brain were weighted. Blood gases and electrolytes were determined with a Nova analyzer, plasma osmolality was determined with an advanced digmatic osmometer. Protein and mRNA of ATR were measured with western blot and real-time PCR in both the forebrain and hindbrain of offspring, and ATG mRNA in brain was also determined. Water intake of adult offspring was detected after intracerebroventricular injection of AngII. The c-Fos positive nuclei, induced by intracerebroventricular injection of AngII, in several concerned brain region were counted, in the adult offspring.Results: Maternal WD during late gestation did not change body and brain weight, blood gases and electrolytes in adult offspring.However maternal WD during late gestation significantly changed ATG mRNA levels, and the ATR mRNA and proteins in both forebrain and hindbrain in the adult offspring. After intracerebroventricular injection of AngII, the adult male offspring in WD group drank more water than that of the control, but the adult female offspring in the WD group drank the same amount of water as that of the control; in the WD group c-Fos positive cell in the several concerned brain regions were significantly increased in WD adult male offspring compared to that in the control.Conclusion: Maternal WD during late gestation showed chronic influence on the brain RAS in the offspring. The"imprinting"effects were suggested by the change of dipsogenic behavior.