Impact On The Regulation Of Blood Pressure And RAS In Offspring By Prenatal Heat Stress Exposure

Objectives:To investigate impact on the regulation of blood pressure and RAS in offspring by prenatal heat stress exposureMethods:The SD rats pregnant for 15 to 18 days were randomly divided into 3 groups, heat stress、stress and control. The fetal body (GD=21d)and the adult offspring were experimented.1) MAP responses induced by intravenous injection of AngⅡ, Losartan, were assessed in adult offspring using femoral artery/vein cannulation.2) In thoracic aorta of adult offspring, dose-response effects triggered by AngⅡwere determined; influences of AngⅡ-induced contraction affected by L-NAME was assessed; meanwhile, alteration of AngⅡ-induced contraction was also observed under the application of Losartan or PD123319.3) Protein of Ang II receptors (ATR) in the fetal kidney were determined with western-blot.4) Protein of Ang II receptors (ATR) in the adult male offspring kidney were determined with western-blot.Results:1) Basic blood pressure responses were remarkably improved in the male adult offspring in heat stress group compared to the control & strss. Blood pressure responses to injection of Ang II and losartan were significantly enhanced in the male adult offspring in heat stress group compared to the control& strss.2)In the thoracic aorta of heat stress adult offspring, AngⅡ-induced contraction responses were all changed compared to control& stress. Compared to control, contraction responses still exists of AngⅡ-induced contraction was also observed under the application of Losartan, but was attenuated in adult offspring of heat stress; contraction responses significantly reduced of AngⅡ-induced contraction was also observed under the application of PD123319.3) Following prenatal exposure to heat stress, the weight of the fetal body and kidney in the offspring was decreased as that of the control& strss, but the fetal kidney/the fetal body was the same as that of the control& strss. Maternal heat stress during pregnancy significantly changed ATR proteins in the fetal kidney. The protein of ATIR were not changed, The protein of AT2R were significantly increased. 4)The protein of ATIR and AT2R receptors in the kidney of adult offspring were measured using western-blot, the results was the same as that of the fetal.Conclusion:Prenatal exposure to heat stress may affect cardiacvascular functions through modulation of vascular functions and AngⅡreceptor expression in the offspring, The "imprinting" effects were caused, and increase risks of development of hypertension.