(218) Physiological Changes in a Mouse Model of Obstructive Sleep Apnea

Introduction: Obstructive sleep apnea (OSA) is a condition characterized by recurrent episodes of upper
airway obstruction during sleep, leading to intermittent hypoxia (IH) and sleep fragmentation.
While the pathophysiological mechanisms underlying OSA remain unclear, it is important to
investigate the changes in physiological parameters that occur following short exposures to IH
in order to gain a better understanding of the condition. In this study, we aimed to examine the
effects of IH on blood pressure (BP), heart rate (HR), core body temperature (CBT), and
activity in a mouse model.

Methods: To simulate OSA, we employed a mouse model of IH. Male C57BL/6J mice were acquired
from Jackson Laboratory and housed in our animal facility with a 12-hour light/12-hour dark
cycle. To assess physiological changes, DSI HD-X10 telemetry probes were surgically
implanted into the carotid artery of mice aged 8 to 10 weeks. Following a two-week surgical
recovery, the mice were divided into two groups: an experimental group exposed to four
weeks of IH during their active phase, and a control group exposed to normal oxygen levels
(normoxia). IH was induced by manipulating the fractional inhaled oxygen concentration
between 21% and 8%, resulting in approximately 50 hypoxic events per hour. Subsequently,
we utilized the DSI telemetry system to measure the impact of IH on various physiological
parameters.

Results: Exposure to four weeks of IH significantly increased CBT, suggesting a disruption in
thermoregulation, but did not exhibit significant effects on BP, HR, and activity levels. These
findings may indicate that disrupted thermoregulation is influenced by IH, a characteristic
feature of OSA

Conclusions: Gaining insights into the initial physiological changes associated with OSA is crucial for early
detection and the development of intervention strategies. The mouse model used in this study
provides valuable information about the physiological consequences of IH, particularly with
regard to alterations in BP, HR, CBT, and activity levels. These findings contribute to a better
understanding of the physiological implications of OSA