AUTHOR=Domnik Nicolle J., Seaborn Geoff , Vincent Sandra G., Akl Selim G., Redfearn Damian P., Fisher John T.

TITLE=OVA-induced airway hyperresponsiveness alters murine heart rate variability and body temperature

JOURNAL=Frontiers in Physiology

VOLUME=3

YEAR=2012

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2012.00456

DOI=10.3389/fphys.2012.00456

ISSN=1664-042X

ABSTRACT=<p>Altered autonomic (ANS) tone in chronic respiratory disease is implicated as a factor in cardiovascular co-morbidities, yet no studies address its impact on cardiovascular function in the presence of murine allergic airway (AW) hyperresponsiveness (AHR). Since antigen (Ag)-induced AHR is used to model allergic asthma (in which ANS alterations have been reported), we performed a pilot study to assess measurement feasibility of, as well as the impact of allergic sensitization to ovalbumin (OVA) on, heart rate variability (HRV) in a murine model. Heart rate (HR), body temperature (T<sub>B</sub>), and time- and frequency-domain HRV analyses, a reflection of ANS control, were obtained in chronically instrumented mice (telemetry) before, during and for 22 h after OVA or saline aerosolization in sensitized (OVA) or Alum adjuvant control exposed animals. OVA mice diverged significantly from Alum mice with respect to change in HR during aerosol challenge (<italic>P</italic> &lt; 0.001, Two-Way ANOVA; HR max change Ctrl = +80 ± 10 bpm vs. OVA = +1 ± 23 bpm, mean ± SEM), and displayed elevated HR during the subsequent dark cycle (<italic>P</italic> = 0.006). Sensitization decreased the T<sub>B</sub> during aerosol challenge (<italic>P</italic> &lt; 0.001). Sensitized mice had decreased HRV <italic>prior</italic> to challenge (SDNN: <italic>P</italic> = 0.038; Low frequency (LF) power: <italic>P</italic> = 0.021; Low/high Frequency (HF) power: <italic>P</italic> = 0.042), and increased HRV during Ag challenge (RMSSD: <italic>P</italic> = 0.047; pNN6: <italic>P</italic> = 0.039). Sensitized mice displayed decreased HRV subsequent to OVA challenge, primarily in the dark cycle (RMSSD: <italic>P</italic> = 0.018; pNN6: <italic>P</italic> ≤ 0.001; LF: <italic>P</italic> ≤ 0.001; HF: <italic>P</italic> = 0.040; LF/HF: <italic>P</italic> ≤ 0.001). We conclude that implanted telemetry technology is an effective method to assess the ANS impact of allergic sensitization. Preliminary results show mild sensitization is associated with reduced HRV and a suppression of the acute T<sub>B</sub>-response to OVA challenge. This approach to assess altered ANS control in the acute OVA model may also be beneficial in chronic AHR models.</p>