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Immunohistochemical
study of VEGF, angiopoietin 2 and their receptors in the
neovascularization following microinjection of C6 glioma cells
into rat brain
Peoch M, Farion R, Hiou A, Le Bas JF, Pasquier B, Remy C
Unite mixte Universite Joseph Fourier/INSERM U438, LCR CEA,
Grenoble, France. Michel.Peoch@chu-grenoble.fr
Background. Recent papers suggest that two angiogenic factors
(angiopoietin 2 and vascular endothelial growth factor) cooperate
in tumoral angiogenesis to support the growing tumor. The purpose
of the present work was to demonstrate the existence of such
cooperation in a longitudinal study of a brain tumor model during
tumor growth by means of immunohistochemistry.
Materials and Methods. The study was performed on 31 rats bearing C6 glioma. At
different stages of tumor growth, the histological aspects were
described and sections were immunostained for VEGF, Ang-2 and
their receptors VEGFR-1, VEGFR-2 and Tie-2. Immunostaining was
semi-quantitatively analyzed and the localization of immunostained
cells was reported.
Results. Ang-2 and Tie-2 were detected in the
endothelial cells of vessels surrounded by tumor cells, occuring
early in our study, with immunostaining taking place from day 4 to
day 24. Immunostaining with VEGF (on tumoral cells) and VEGFR-2
(on endothelial cells) was present after 8 days of tumor growth. A
clear increase of vessel density can be observed at the periphery
of the tumors after 16 days of tumor growth. At that time, areas
of necrosis were present in the tumor with concomitant VEGF and
Ang-2 expression.
Conclusion. The present study demonstrated
cooperation between the early effect of Ang-2 and the secondary
effect of VEGF to elaborate new vessels in a longitudinal study of
experimental brain tumors. This study is favorable to the new
model of tumor angiogenesis, with successive vessel cooption,
regression and growth mediated by angiopoietins and VEGF.
PMID: 12174896 [PubMed - indexed for MEDLINE]
Source: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12174896
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