title: Cerebral oxygen metabolism of rats using injectable (15)O-oxygen with a steady-state method.
abstract: To develop a less-stressful and simple method for measurement of the cerebral metabolic rate of oxygen (CMRO(2)) in small animals, the steady-state method was applied to injectable (15)O(2)-PET ((15)O(2)-positron emission tomography) using hemoglobin-containing vesicles ((15)O(2)-HbV). Ten normal rats and 10 with middle cerebral arterial occlusion (MCAO) were studied using a small animal PET scanner. A series of (15)O-PET scans with C(15)O-labeled HbV, H(2)(15)O, and (15)O(2)-HbV were performed with 10 to 15 minutes intervals to measure cerebral blood volume (CBV), cerebral blood flow (CBF), and CMRO(2). Positron emission tomography scans were started with a tracer injection using a multiprogramming syringe pump, which provides a slowly increasing injection volume to achieve steady-state radioactivity for H(2)(15)O and (15)O(2)-HbV scans. The radioactivity concentration of (15)O rapidly achieved equilibrium in the blood and whole brain at about 2 minutes after H(2)(15)O and (15)O(2)-HbV administration, which was stable during the scans. The whole brain mean values of CBF, CBV, and CMRO(2) were 54.3±2.0 mL per 100 g per minute, 4.9±0.4 mL/100 g, and 2.8±0.2 μmoL per g per minute (6.2±0.4 mL per 100 g per minute) in the normal rats, respectively. In the MCAO model rats, all hemodynamic parameters of the infarction area on the occlusion side significantly decreased. The steady-state method with (15)O-labeled HbV is simple and useful to analyze hemodynamic changes in studies with model animals.
authors.affiliation: Biomedical Imaging Research Center, University of Fukui, Eiheiji-cho, Fukui, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mori
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kiyono
authors.forename: Vijay Narayan
authors.initials: VN
authors.lastname: Tiwari
authors.forename: Rikiya
authors.initials: R
authors.lastname: Maruyama
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kawai
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Okazawa
mesh_terms: D000818:Animals; D001810:Blood Volume / Q000502:physiology*; D002540:Cerebral Cortex / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D010104:Oxygen Radioisotopes; D010100:Oxygen