title: Aging-related differences in cerebral capillary blood flow in anesthetized rats.
abstract: Age-related decreases in baseline cerebral blood flow have been measured with various imaging modalities, however, the contribution of capillary flow to this phenomenon remain to elucidate. This study used 2-photon laser scanning fluorescence microscopy to measure capillary diameter, red blood cell speed, and flux in individual capillaries in the sensory-motor cortex of 12 adult (3-month-old) and 12 old (24-month-old) male Long-Evans rats under isoflurane anesthesia. The average (± standard deviation) diameter and speed over 921 capillaries were 6.4 ± 1.4 μm and 1.3 ± 1.1 mm/s, respectively. Red blood cell speed and flux were significantly higher, by 48% and 15%, respectively, in old compared with young animals (p < 5%). The diameter also showed a similar tendency (7% higher, p = 5.7%). Furthermore, capillary hematocrit and density were significantly lower in the older group (p < 5%), by 32% and 20%, respectively.
authors.affiliation: Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Montreal Heart Institute, Montréal, Quebec, Canada. Electronic address: michele.desjardins@polymtl.ca.
authors.forename: Michèle
authors.initials: M
authors.lastname: Desjardins
authors.affiliation: Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Montreal Heart Institute, Montréal, Quebec, Canada.
authors.forename: Romain
authors.initials: R
authors.lastname: Berti
authors.affiliation: Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
authors.forename: Joël
authors.initials: J
authors.lastname: Lefebvre
authors.affiliation: Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Montreal Heart Institute, Montréal, Quebec, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Dubeau
authors.affiliation: Department de Génie Électrique, Institut de Génie Biomédical, École Polytechnique de Montréal, Montréal, Quebec, Canada; Montreal Heart Institute, Montréal, Quebec, Canada; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lesage
mesh_terms: D000375:Aging / Q000473:pathology / Q000502:physiology*; D000758:Anesthesia; D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology*; D002196:Capillaries / Q000473:pathology / Q000502:physiology* / Q000648:ultrastructure; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D004912:Erythrocytes / Q000378:metabolism; D006400:Hematocrit; D008297:Male; D036641:Microscopy, Fluorescence, Multiphoton; D010100:Oxygen / Q000097:blood; D051381:Rats; D020318:Rats, Long-Evans
chemical_list: D010100:Oxygen
keywords: Aging; Capillary; Cerebral blood flow; Hematocrit; Rat; Two-photon microscopy