A Novel Rabbit Carotid Body and Common Carotid Artery Model in Vivo for the Simulation of Various Intermittent and Continuous Hypoxia Modes / 中国呼吸与危重监护杂志

ABSTRACT

Objective To develope a novel rabbit carotid body and carotid common artery model in vivo for the simulation of various intermittent hypoxia (IH) intensities, IH durations, IH reoxygenation (ROX) durations and continuous hypoxia (CH) modes.Methods Forty-five adult New Zealand rabbits (2.5～3.0 kg) were anesthetized while spontaneous breathing kept intact.The tissue surrounding the fight earetid common artery and carotid sinus nerve (CSN) were cleared and "single" chemoreceptor bundle of the CSN was revealed.Then suction electrodes were placed and CSN afferent activity was monitored and recorded carefully.The fight common carotid artery was exposed, cannulated to distal part and its proximal part was ligated.Preparations were challenged by changing the PO2 of the gas mixture equilibrating the perfusate.Alternatively perfusion (2 mL/min) of equilibrated porfusate bubbled with normoxia or hypoxia gas mixtures formed IH/ROX cycles in carotid common artery,simulating the pattern of hypoxic episodes seen in obstructive sleep apnea syndrome (OSAS), or with continuously perfusing hypoxia perfusate to form CH modes.All the perfusing procedures were regulated by a customized computer-controlled set and monitored using O2 gas analyzer.After the systematic exposures, carotid body, carotid common artery part distal to cannula,and carotid bifurcation were harvested as samples.Results The frequencies and average amplitudes of CSN chemoreceptor bundles afferent activities with normoxia peffusion were (0.17±0.03) impulse/s and (46.2±4.4) μV, and with hypoxia perfusion were (0.6±0.09) impulse/s and (87.4±6.6) μV, respectively.PO2 was (139±1.5) nun Hg in normoxia perfusate and (35.2±1.3) mm Hg in hypoxia perfusate.Conclusion This new carotid body and carotid common artery model is a valuable tool to study neurological and biochemical changes in various IH and CH modes.