Frequency distribution function of red blood cell velocities in single capillaries of the rat cerebral cortex using intravital laser-scanning confocal microscopy with highspeed camera

Miyuki Unekawa, Minoru Tomita, Takashi Osada, Yutaka Tomita, Haruki Toriumi, Jemal Tatarishvili, Norihiro Suzuki

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Background: Brain metabolism depends largely on oxygen and therefore constant delivery of oxygen to the brain is more important than to any other organ. Previously we reported a newly developed method to automatically calculate red blood cell (RBC) flow and its temporal modulations at the layer 1 of the rat cerebral cortex. Objective: To examine a general tendency of frame-rate dependency of RBC velocities and heterogeneity of RBC movements in single capillaries identified by fluorescein isothiocyanate (FITC)-dextran staining. Methods: In urethane-anesthetized rats with a closed cranial window, intravenously administered FITC-labeled RBCs were traced at 125, 250 or 500 frames/s (fps) with a laser-scanning confocal fluorescence microscope and their velocities were automatically calculated with home-made software KEIO-IS2. Results: RBC velocities in single capillaries were not constant but variable, and were dependent on frame rate, with average values of 0.85 ± 0.43 mm/s at 125 fps, 1.34 ± 0.73 mm/s at 250 fps, and 2.05 1.59 mm/s at 500 fps. When all capillary RBCs were plotted against their velocities (frequency distribution function of RBC velocities), RBC velocities were clustered at around 1.0 mm/s, smearing at higher velocities up to 9.4 mm/s. High RBC velocity was only detected from frame analysis with high frame rates since such high-flow RBCs were uncounted at low frame rates. RBC velocities higher than 6.5 mm/s were statistically significantly outlined from the main population (p<.01). Such a group of capillaries was considered to belong to thoroughfare channels, although their diameter was almost the same as that of ordinary ones. Conclusion: Extra-high flow capillaries are confirmed in the cerebral cortex and these may be thoroughfare channels or non-nutritional capillaries carrying 42 % of the blood in reserve.

Original languageEnglish
Pages (from-to)203-218
Number of pages16
JournalAsian Biomedicine
Volume2
Issue number3
Publication statusPublished - 2008 Jun

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Confocal microscopy
Confocal Microscopy
Cerebral Cortex
Probability density function
Distribution functions
Rats
Blood
Erythrocytes
Cameras
Cells
Scanning
Lasers
Brain
Oxygen
Capillary flow
Urethane
Fluorescein
Cell Movement
Metabolism
Software

Keywords

  • High-speed camera
  • Intraparenchymal single capillary
  • KEIO-IS2
  • Laser-scanning confocal fluorescencemicroscopy
  • RBC velocity
  • Thoroughfare channel

ASJC Scopus subject areas

  • Medicine(all)
  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Frequency distribution function of red blood cell velocities in single capillaries of the rat cerebral cortex using intravital laser-scanning confocal microscopy with highspeed camera. / Unekawa, Miyuki; Tomita, Minoru; Osada, Takashi; Tomita, Yutaka; Toriumi, Haruki; Tatarishvili, Jemal; Suzuki, Norihiro.

In: Asian Biomedicine, Vol. 2, No. 3, 06.2008, p. 203-218.

Research output: Contribution to journalArticle

Unekawa, Miyuki ; Tomita, Minoru ; Osada, Takashi ; Tomita, Yutaka ; Toriumi, Haruki ; Tatarishvili, Jemal ; Suzuki, Norihiro. / Frequency distribution function of red blood cell velocities in single capillaries of the rat cerebral cortex using intravital laser-scanning confocal microscopy with highspeed camera. In: Asian Biomedicine. 2008 ; Vol. 2, No. 3. pp. 203-218.
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T1 - Frequency distribution function of red blood cell velocities in single capillaries of the rat cerebral cortex using intravital laser-scanning confocal microscopy with highspeed camera

AU - Unekawa, Miyuki

AU - Tomita, Minoru

AU - Osada, Takashi

AU - Tomita, Yutaka

AU - Toriumi, Haruki

AU - Tatarishvili, Jemal

AU - Suzuki, Norihiro

PY - 2008/6

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AB - Background: Brain metabolism depends largely on oxygen and therefore constant delivery of oxygen to the brain is more important than to any other organ. Previously we reported a newly developed method to automatically calculate red blood cell (RBC) flow and its temporal modulations at the layer 1 of the rat cerebral cortex. Objective: To examine a general tendency of frame-rate dependency of RBC velocities and heterogeneity of RBC movements in single capillaries identified by fluorescein isothiocyanate (FITC)-dextran staining. Methods: In urethane-anesthetized rats with a closed cranial window, intravenously administered FITC-labeled RBCs were traced at 125, 250 or 500 frames/s (fps) with a laser-scanning confocal fluorescence microscope and their velocities were automatically calculated with home-made software KEIO-IS2. Results: RBC velocities in single capillaries were not constant but variable, and were dependent on frame rate, with average values of 0.85 ± 0.43 mm/s at 125 fps, 1.34 ± 0.73 mm/s at 250 fps, and 2.05 1.59 mm/s at 500 fps. When all capillary RBCs were plotted against their velocities (frequency distribution function of RBC velocities), RBC velocities were clustered at around 1.0 mm/s, smearing at higher velocities up to 9.4 mm/s. High RBC velocity was only detected from frame analysis with high frame rates since such high-flow RBCs were uncounted at low frame rates. RBC velocities higher than 6.5 mm/s were statistically significantly outlined from the main population (p<.01). Such a group of capillaries was considered to belong to thoroughfare channels, although their diameter was almost the same as that of ordinary ones. Conclusion: Extra-high flow capillaries are confirmed in the cerebral cortex and these may be thoroughfare channels or non-nutritional capillaries carrying 42 % of the blood in reserve.

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KW - Intraparenchymal single capillary

KW - KEIO-IS2

KW - Laser-scanning confocal fluorescencemicroscopy

KW - RBC velocity

KW - Thoroughfare channel

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