Live imaging of primary ocular vasculature formation in zebrafish

PLoS One. 2017 Apr 26;12(4):e0176456. doi: 10.1371/journal.pone.0176456. eCollection 2017.

Abstract

Ocular vasculature consists of the central retinal and ciliary vascular systems, which are essential to maintaining visual function. Many researchers have attempted to determine their origins and development; however, the detailed, stepwise process of ocular vasculature formation has not been established. In zebrafish, two angioblast clusters, the rostral and midbrain organizing centers, form almost all of the cranial vasculature, including the ocular vasculature, and these are from where the cerebral arterial and venous angioblast clusters, respectively, differentiate. In this study, we first determined the anatomical architecture of the primary ocular vasculature and then followed its path from the two cerebral angioblast clusters using a time-lapse analysis of living Tg(flk1:EGFP)k7 zebrafish embryos, in which the endothelial cells specifically expressed enhanced green fluorescent protein. We succeeded in capturing images of the primary ocular vasculature formation and were able to determine the origin of each ocular vessel. In zebrafish, the hyaloid and ciliary arterial systems first organized independently, and then anastomosed via the inner optic circle on the surface of the lens by the lateral transfer of the optic vein. Finally, the choroidal vascular plexus formed around the eyeball to complete the primary ocular vasculature formation. To our knowledge, this study is the first to report successful capture of circular integration of the optic artery and vein, lateral transfer of the optic vein to integrate the hyaloidal and superficial ocular vasculatures, and formation of the choroidal vascular plexus. Furthermore, this new morphological information enables us to assess the entire process of the primary ocular vasculature formation, which will be useful for its precise understanding.

MeSH terms

  • Animals
  • Animals, Genetically Modified / metabolism
  • Embryo, Nonmammalian / metabolism
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Imaging, Three-Dimensional
  • In Situ Hybridization
  • Microscopy, Fluorescence, Multiphoton
  • Retinal Artery / anatomy & histology*
  • Retinal Artery / pathology
  • Retinal Artery / physiology
  • Retinal Vein / anatomy & histology*
  • Retinal Vein / pathology
  • Retinal Vein / physiology
  • Time-Lapse Imaging*
  • Zebrafish / growth & development
  • Zebrafish / physiology*

Substances

  • enhanced green fluorescent protein
  • Green Fluorescent Proteins

Grants and funding

Iwate Medical University provided support in the form of salaries for all authors. This work was supported by Grant-in-Aid for Scientific Research (KAKENHI) of the Japan Society for the Promotion of Science (JSPS), grant numbers 20390054 (EK and JH), and partly supported by a Grant-in-Aid for Strategic Medical Science Research (S1491001, 2014-2018) from the Ministry of Education, Culture, Sports, Science and Technology of Japan (EK and JH) and the NIBB Cooperative Research Program number 15-701 (EK). None of the funders had any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.