Dynamic Two-Photon Imaging of Cerebral Microcirculation Using Fluorescently Labeled Red Blood Cells and Plasma

  • Kazuto Masamoto
  • Hiroshi Kawaguchi
  • Hiroshi Ito
  • Iwao Kanno
Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 765)

Abstract

To explore the spatiotemporal dynamics of red blood cells (RBCs) and plasma flow in three-dimensional (3D) microvascular networks of the cerebral cortex, we performed two-photon microscopic imaging of the cortical microvasculature in genetically engineered rats in which the RBCs endogenously express green fluorescent protein (GFP). Water-soluble quantum dots (Qdots) were injected intravenously into the animals to label the plasma, and concurrent imaging was performed for GFP-RBCs and Qdot plasma. The RBC and plasma distributions were compared between resting state and forepaw stimulation-induced neural activation. The RBC and plasma images showed detectable signals up to a depth of 0.4 and 0.6 mm from the cortical surface, respectively. A thicker plasma layer (2–5 μm) was seen in venous vessels relative to the arterial vessels. In response to neural activation, the RBCs were redistributed among the parenchymal capillary networks. In addition, individual capillaries showed a variable ratio of RBC and plasma distributions before and after activation, indicative of dynamic changes of hematocrit in single capillaries. These results demonstrate that this transgenic animal model may be useful in further investigating the mechanism that controls dynamic RBC flow in single capillaries and among multiple capillary networks of the cerebral microcirculation.

Keywords

Brain microcirculation Functional imaging Oxygen demand and supply Somatosensory cortex 

Notes

Acknowledgments

The authors thank Dr. Junko Taniguchi for help with the experiments. This work was partly supported by Special Coordination Funds for Promoting Science and Technology (K.M.).

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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Kazuto Masamoto
    • 1
    • 2
  • Hiroshi Kawaguchi
    • 2
  • Hiroshi Ito
    • 2
  • Iwao Kanno
    • 2
  1. 1.Center for Frontier Science and EngineeringUniversity of Electro-CommunicationsChofuJapan
  2. 2.Molecular Imaging CenterNational Institute of Radiological SciencesChibaJapan

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