Noninvasive uterine and umbilical blood flow changes and variates the expressions of angiogenic proteins and fetal growth: Behavioral study in pregnant Ossimi sheep

Abstract

<title>Abstract</title> The objective of this prospective study was to investigate whether Doppler- and B-mode sonography could be used to assess a possible influence of maternal temperament on fetal and pregnancy-related endpoints in sheep during pregnancy. On the basis of behavioral testing related to an anxiety-eliciting stimulus (arena test), 20 sheep were divided into two groups, namely more reactive/anxious (MR: 12 sheep) and less reactive/anxious (LR: 8 sheep). After mating, several endpoints were assessed by transrectal and/or transabdominal ultrasonography every 2 weeks (wk) from breeding to wk 20 of pregnancy and blood samples were taken to evaluate the expression of angiogenic proteins at parturition. Gestational length, fetal weight and fetal numbers were also investigated. The resistance index (RI), as well as the pulsatility index (PI) of the uterine (UtA) and the fetal umbilical arteries (UMA), were measured with non-invasive Doppler sonography. Further parameters were measured with B-mode ultrasonography: diameter of amniotic vesicles (AVD; only wk 2–8), umbilicus (UMD), fetal chest (FCHD), and metacarpal length (MCL). The UtA-PI was significantly higher in MR compared to LR ewes at pregnancy between 6–12 wks (P &gt; 0.01), while a tendency was recognized at wk 14 (P = 0.054). The same was true for UtA-RI during the first 8 wk of pregnancy (P &lt; 0.03) when MR and LR animals were compared. Similarly, UMA-RI was higher in fetuses of MR than LR ewes at wk 14 (P &lt; 0.0003) and 20 (P &lt; 0.02) of pregnancy. The differences in UMA-PI reached significance at wk 6, 8, 10, and 20 (P &lt; 0.05–0.003). Furthermore, AVD (P &lt; 0.03, wk 2–8), FCHD (P &lt; 0.002, wk 8–18) as well as the UMD (P &lt; 0.054, wk 8–18) were higher in LR than MR pregnant ewes. A significant variation in the gestational length, fetal weight and fetal numbers were recorded. The expressions of <italic>VEGF, NOS3</italic> and <italic>VEGFR1</italic> protein genes was increased in the less reactive sheep (P &lt; 0.001). In conclusion, using Doppler- and B-mode sonography, the effects of maternal temperament on fetal growth, as well as maternal and umbilical blood flow in sheep could be successfully demonstrated. The maternal anxiety affects the expression of mRNAs for <italic>VEGF, NOS3</italic> and <italic>HIF 1α</italic> at time of parturition.