Tissue oxygen tension and blood-flow changes in rat incisor pulp with graded systemic hyperoxia
- 作者：Yu ; Christine Y. ; Boyd ; Nick M. ; Cringle ; Stephen J. ; Alder ; Valerie A. ; Yu ; Dao-Yi
- 关键词：Rat incisor pulp ; Pulpal blood-flow ; Laser Doppler flowmeter ; Oxygen-sensitive microelectrode ; Pulpal tissue oxygen tension ; Systemic hyperoxia
- 刊名：Archives of Oral Biology
- 出版年：2002
- 期刊代码：25_00039969
- 类别：med
- 出版时间：March, 2002
- 卷：47
- 期：3
- 页码：239-246
- 文件大小：195 K
摘要
The role of oxygen in the regulation of the pulpal microcirculation is unknown. This investigation is aimed to measure tissue oxygen tension and blood-flow changes in the pulp of rat lower incisors during graded systemic hyperoxia, and to determine the response of the pulpal vasculature to various oxygen tensions. Twenty-four Sprague–Dawley rats were anaesthetized and artificially ventilated with the appropriate gas mixture. Recessed oxygen-sensitive microelectrodes were used to measure pulpal tissue oxygen tension via a small access cavity filled with saline on the labial surface of the incisor. A laser Doppler flowmeter was used to record pulpal blood-flow. Inspired oxygen was increased stepwise from 20 to 100%in 20%steps. Systemic blood-gas concentrations were measured at each step. Systemic arterial oxygen tension at 100%oxygen ventilation reached 481.2±30.7%of the baseline at 20%oxygen breathing (n=21). Pulpal tissue oxygen tension did not change significantly whereas pulpal blood-flow fell dose-dependently to 74.6±5.0%at 100%oxygen ventilation (n=21). Systemic hyperoxia, therefore, induces a significant reduction in pulpal blood-flow whereas pulpal tissue oxygen tension remains relatively stable, indicating an oxygen-dependent local regulatory mechanism.