Does Shipping Late‐Gestation Rats Alter Respiratory Control in Their Offspring?

Abstract

Ordering timed‐pregnant rats is convenient for many developmental studies, but the shipping process may be stressful for the animals. Given the sensitivity of the developing respiratory control system to perinatal stress (e.g., Joseph et al., Respir Physiol Neurobiol 185:75–86, 2013), we investigated whether prenatal “shipping stress” alters the respiratory control of neonatal rats. In the first set of experiments, timed‐pregnant rats were shipped to arrive at our animal facility at embryonic age 17 (E17) and their pups were compared to those of rats bred in‐house (IH) at 8–9 days of age (P8–9). Normoxic ventilation (measured by head‐body plethysmography) was 30% greater in E17 pups than in IH pups (138±6 vs. 106±4 ml min−1 100g−1; mean±SEM, P<0.001), and their hypoxic ventilatory responses (HVR) to 12% O2 were lower (45±6 vs. 67±4 % increase from baseline; P=0.02). We then repeated the experiment with timed‐pregnant rats shipped to arrive at E13 or E19. At P4–5, ventilation was approximately 10% greater in E19 pups than in E13 or IH pups (treatment, P=0.02), but the magnitude and time course of the HVR was similar among groups (treatment × time, P=0.53). At P11–12, no differences in normoxic or hypoxic ventilation were detected among the treatment groups (treatment, P=0.24; treatment × time, P=0.08). Similarly, in vitro carotid body responses to hypoxia did not differ among E13, E19, and IH groups at either age (both P>0.05). The different outcomes of these studies could reflect the different gestational ages at which the rats were shipped or different origins/shipping distances of the pregnant rats (Portage, MI vs. Kingston, NY).Support or Funding InformationSupported by NIH grant P20 GM‐103423 (Maine INBRE).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.