TY - JOUR
T1 - A method for measuring brain partial pressure of oxygen in unanesthetized unrestrained subjects
T2 - The effect of acute and chronic hypoxia on brain tissue PO2
AU - Ortiz-Prado, E.
AU - Natah, Siraj
AU - Srinivasan, Sathyanarayanan
AU - Dunn, Jeff F.
N1 - Funding Information:
This work was supported by National Institutes of Health (NIH RO1 EB002085 ), Canadian Institutes of Health Research, the Canadian Foundation for Innovation, the National Sciences and Engineering Research Council and the Alberta Heritage Foundation. Thanks are given to members of Oxford Optronics, who worked patiently and diligently to construct the implantible fibers and to the help of Dr. Cam Teskey (and Jenn Vuong), who provided the data on PtO 2 in the 2 week and 3–5-week control subjects.
PY - 2010/11/30
Y1 - 2010/11/30
N2 - The level of tissue oxygenation provides information related to the balance between oxygen delivery, oxygen utilization, tissue reactivity and morphology during physiological conditions. Tissue partial pressure of oxygen (PtO2) is influenced by the use of anesthesia or restraint. These factors may impact the absolute level of PtO2. In this study we present a novel fiber optic method to measure brain PtO2. This method can be used in unanesthetized, unrestrained animals, provides absolute values for PO2, has a stable calibration, does not consume oxygen and is MRI compatible. Brain PtO2 was studied during acute hypoxia, as well as before and after 28 days of high altitude acclimatization. A sensor was chronically implanted in the frontal cortex of eight Wistar rats. It is comprised of a fiber optic probe with a tip containing material that fluoresces with an oxygen dependent lifetime. Brain PtO2 declines by 80% and 76% pre- and post-acclimatization, respectively, when the fraction of inspired oxygen declines from 0.21 to 0.08. In addition, a linear relationship between brain PtO2 and inspired O2 levels was demonstrated r2=0.98 and r2=0.99 (pre- and post-acclimatization). Hypoxia acclimatization resulted in an increase in the overall brain PtO2 by approximately 35%. This paper demonstrates the use of a novel chronically implanted fiber optic based sensor for measuring absolute PtO2. It shows a very strong linear relationship in awake animals between inspired O2 and tissue O2, and shows that there is a proportional increase in PtO2 over a range of inspired values after exposure to chronic hypoxia.
AB - The level of tissue oxygenation provides information related to the balance between oxygen delivery, oxygen utilization, tissue reactivity and morphology during physiological conditions. Tissue partial pressure of oxygen (PtO2) is influenced by the use of anesthesia or restraint. These factors may impact the absolute level of PtO2. In this study we present a novel fiber optic method to measure brain PtO2. This method can be used in unanesthetized, unrestrained animals, provides absolute values for PO2, has a stable calibration, does not consume oxygen and is MRI compatible. Brain PtO2 was studied during acute hypoxia, as well as before and after 28 days of high altitude acclimatization. A sensor was chronically implanted in the frontal cortex of eight Wistar rats. It is comprised of a fiber optic probe with a tip containing material that fluoresces with an oxygen dependent lifetime. Brain PtO2 declines by 80% and 76% pre- and post-acclimatization, respectively, when the fraction of inspired oxygen declines from 0.21 to 0.08. In addition, a linear relationship between brain PtO2 and inspired O2 levels was demonstrated r2=0.98 and r2=0.99 (pre- and post-acclimatization). Hypoxia acclimatization resulted in an increase in the overall brain PtO2 by approximately 35%. This paper demonstrates the use of a novel chronically implanted fiber optic based sensor for measuring absolute PtO2. It shows a very strong linear relationship in awake animals between inspired O2 and tissue O2, and shows that there is a proportional increase in PtO2 over a range of inspired values after exposure to chronic hypoxia.
KW - Anesthesia
KW - Brain
KW - High altitude
KW - Hypoxia
KW - Oxygen
KW - Partial pressure of oxygen
KW - Unrestrained
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U2 - 10.1016/j.jneumeth.2010.08.019
DO - 10.1016/j.jneumeth.2010.08.019
M3 - Article
C2 - 20817029
AN - SCOPUS:78049378348
SN - 0165-0270
VL - 193
SP - 217
EP - 225
JO - Journal of Neuroscience Methods
JF - Journal of Neuroscience Methods
IS - 2
ER -