Effects of improving intermittent hypoxia on poststroke Recovery: Role of cardiovascular status and sleep patterns in animal models

Stroke patients exhibit a higher prevalence of sleep apnea (SA); however, the SA symptom, intermittent hypoxia (IH)-induced progression of cardiovascular function and sleep status in these patients remains unclear. We explore the IH-triggered cardiovascular autonomic dysfunction, blood pressure (BP) instability, abnormal baroreflex sensitivity and sleep disorders following middle cerebral artery occlusion (MCAO) and cessation of IH post-MCAO to stroke outcomes. Ten-week-old male Wistar–Kyoto rats were randomly assigned to either room air (RA) exposure or IH exposure for 2 weeks, followed by MCAO induction. The IH group was further categorized into IH-IH (continual IH) and IH-RA (transition to RA) subgroups. Physiological signals were recorded, sensorimotor and cognitive behavior were evaluated post-MCAO. The rats’ brain were stained to estimate infarct volume. The IH-RA group exhibited reduced brain infarct volume, faster sensorimotor behavior recovery, better cognitive performance, and alleviated each surge of BP with episode of hypoxia. Moreover, the IH-RA group demonstrated progressively improved autonomic activity, stable sleep pattern, increased delta brainwave power, and reduced interruptions during sleep. Among these factors, stable BP and sleep patterns had stronger correlation with outcomes. In this study, we found that increased BP surges during hypoxic episodes may serve as an indicator of SA in stroke patients. In addition, this study highlights the importance of promptly treating IH after stroke, underscoring stabilizing the surge in BP and sleep patterns for treatment of stroke patients who exhibit sleep apnea by preventing poor sequelae.