Corncob bedding alters fasting blood glucose and vascular function in mice

Abstract

Rodent husbandry requires careful consideration of environmental factors that may impact colony performance and subsequent physiological studies. Of note, recent reports have suggested corncob bedding is potentially a confounding variable affecting a broad range of organ systems. As corncob bedding may contain digestible hemicelluloses, trace sugars, and fiber, we hypothesized that corncob bedding impacts murine vascular function and overnight fasting blood glucose. Here, we compared mice housed on corncob bedding, which were then fasted overnight on either corncob or ALPHA-dri bedding, a paper cellulose alternative. Male and female mice were used from two non-induced, endothelial-specific conditional knock-out strains (Cadherin 5-CreERT2, floxed hemoglobin alpha 1 [Hba1] or Cadherin 5-CreERT2, floxed cytochrome B5 reductase 3 [CyB5R3]) on a C57BL/6J genetic background. After fasting overnight, initial blood glucose was measured, and mice were anesthetized with isoflurane for measurement of blood perfusion via laser speckle contrast analysis using a PeriMed PeriCam PSI NR system. After a 15-minute equilibration, the mice were injected intraperitoneally with phenylephrine (5 mg/kg) or saline and monitored for changes in blood perfusion. After a 15-minute response period, blood glucose was remeasured post-procedure. Consistently, mice fasted on corncob bedding had higher blood glucose than the ALPHA-dri group. In the CyB5R3 strain, corncob bedding caused a reduction in phenylephrine-mediated vasoconstriction. In the Hba1 strain, phenylephrine-induced vasoconstriction was more variable in the corncob group. Altogether, this work suggests that corncob bedding could be a confounding variable for vascular measurements and fasting blood glucose in mice. To promote scientific rigor and improve reproducibility, bedding type should be included in published methods. NIH R01HL155618 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.