Abstract
Purpose: :
To quantify site-specific effects of triamcinolone acetonide (TA) on the angiogenic microvascular tree of the chorioallantoic membrane (CAM) of quail embryos using the vascular mapping and quantification software VESGEN (for Generational Analysis of Vessel Branching). The CAM is an experimental model of angiogenic remodeling that displays some useful morphological characteristics similar to retinal neovascularization, such as quasi-two dimensional arterial and venous trees.
Methods: :
TA (0-16 ng/ml) was applied to the CAM on embryonic day 7 (E7) and incubated further for an additional 24 hours until fixation. Binary (black/white) microscopic images of arterial end points were analyzed by VESGEN for major vascular parameters that include vessel diameter (Dv), fractal dimension (Df), tortuosity (Tv) and densities of vessel area, length, number and branch point (Av, Lv, Nv and Brv). VESGEN automatically segments the vascular tree into branching generations (G1...Gx) according to changes in vessel diameter and branching.
Results: :
By Av, Lv, Brv, Nv and Df, vessel density decreased up to 34% as the function of increasing concentration of TA, and the growth of new, small vessels was selectively inhibited throughout ten branching generations (G1-G10). For example, Lv decreased from 13.14 ± 0.61 cm/cm2 for controls to 8.012 ± 0.82 cm/cm2 at 16 ng TA/ml in smaller branching generations (G7-G10) and Nv, from 473.83 ± 29.85 cm-2 to 302.32 ± 33.09 cm-2. In contrast, vessel diameter (Dv) decreased within all branching generations of the vascular tree (G1-G10).
Conclusions: :
By VESGEN analysis, application of TA to the highly angiogenic CAM selectively altered vascular growth by inhibiting the growth of new small vessels and decreasing vessel diameter throughout the vascular tree.
Keywords: retinal neovascularization • inflammation • pathology: experimental