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3D Analysis of Intracortical Microvasculature During Chronic Hypoxia in Mouse Brains

  • Kouichi Yoshihara
  • Hiroyuki Takuwa
  • Iwao Kanno
  • Shinpei Okawa
  • Yukio Yamada
  • Kazuto Masamoto
Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 765)

Abstract

The purpose of this study is to determine when and where the brain microvasculature changes its network in response to chronic hypoxia. To identify the hypoxia-induced structural adaptation, we longitudinally imaged cortical microvasculature at the same location within a mouse somatosensory cortex with two-photon microscopy repeatedly for up to 1 month during continuous exposure to hypoxia (either 8 or 10% oxygen conditions). The two-photon microscopy approach made it possible to track a 3D pathway from a cortical surface arteriole to a venule up to a depth of 0.8 mm from the cortical surface. The network pathway was then divided into individual vessel segments at the branches, and their diameters and lengths were measured. We observed 3–11 vessel segments between the penetrating arteriole and the emerging vein over the depths of 20–460 μm within the 3D reconstructed image (0.46 × 0.46 × 0.80 mm3). The average length of the individual capillaries (<7 μm in diameter) was 67 ± 46 μm, which was not influenced by hypoxia. In contrast, 1.4 ± 0.3 and 1.2 ± 0.2 fold increases of the capillary diameter were observed 1 week after exposure to 8 % and 10% hypoxia, respectively. At 3 weeks from the exposure, the capillary diameter reached 8.5 ± 1.9 and 6.7 ± 1.8 μm in 8% and 10 % hypoxic conditions, respectively, which accounted for the 1.8 ± 0.5 and 1.4 ± 0.3 fold increases relative to those of the prehypoxic condition. The vasodilation of penetrating arterioles (1.4 ± 0.2 and 1.2 ± 0.2 fold increases) and emerging veins (1.3 ± 0.2 and 1.3 ± 0.2 fold increases) showed relatively small diameter changes compared with the parenchymal capillaries. These findings indicate that parenchymal capillaries are the major site responding to the oxygen environment during chronic hypoxia.

Keywords

Two-photon microscopy Oxygen transport Hypoxic adaptation Somatosensory cortex 

Notes

Acknowledgments

The authors thank Mr. Ryutaro Asaga and Mr. Ryota Sakamoto for their help in the preparation of the experiments. This work was partially supported by Special Coordination Funds for Promoting Science and Technology (K.M.).

References

  1. 1.
    Masamoto K, Tanishita K (2009) Oxygen transport in brain tissue. J Biomech Eng 131:074002CrossRefGoogle Scholar
  2. 2.
    Boero JA, Ascher J, Arregui A et al (1999) Increased brain capillaries in chronic hypoxia. J Appl Physiol 86:1211–1219CrossRefGoogle Scholar
  3. 3.
    Xu K, LaManna JC (2006) Chronic hypoxia and the cerebral circulation. J Appl Physiol 100:725–730CrossRefGoogle Scholar
  4. 4.
    Wsseling P, Ruiter DJ, Burger PC (1997) Angiogenesis in brain tumors; pathobiological and clinical aspects. J Neurooncol 32:253–265CrossRefGoogle Scholar
  5. 5.
    Meyer EP, Ulmann-Schuler A, Staufenbiel M et al (2008) Altered morphology and 3D architecture of brain vasculature in a mouse mode for Alzheimer’s disease. Proc Natl Acad Sci U S A 105:3587–3592CrossRefPubMedPubMedCentralGoogle Scholar
  6. 6.
    Denk W, Strickler JH, Webb WW (1990) Two-photon laser scanning fluorescence microscopy. Science 248:73–76CrossRefGoogle Scholar
  7. 7.
    So PT, Dong CY, Masters BR et al (2000) Two-photon excitation fluorescence microscopy. Annu Rev Biomed Eng 2:399–429CrossRefPubMedGoogle Scholar
  8. 8.
    Helmchen F, Denk W (2005) Deep tissue two-photon microscopy. Nat Methods 2:932–940CrossRefPubMedPubMedCentralGoogle Scholar
  9. 9.
    Yamada Y (1995) Light-tissue interaction and optical imaging in biomedicine. Ann Rev Heat Transfer 6:1–59CrossRefGoogle Scholar
  10. 10.
    Takuwa H, Autio J, Nakayama H et al (2011) Reproducibility and variance of a stimulation-induced hemodynamic response in barrel cortex of awake behaving mice. Brain Res 1369:103–111CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Kouichi Yoshihara
    • 1
  • Hiroyuki Takuwa
    • 2
  • Iwao Kanno
    • 2
  • Shinpei Okawa
    • 1
  • Yukio Yamada
    • 1
  • Kazuto Masamoto
    • 2
    • 3
  1. 1.Department of Mechanical Engineering and Intelligent SystemsUniversity of Electro-CommunicationsChofuJapan
  2. 2.Molecular Imaging Center, National Institute of Radiological SciencesChibaJapan
  3. 3.Center for Frontier Science and EngineeringUniversity of Electro-CommunicationsChofuJapan

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