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Discussion:
From
the first experiment, bFGF was shown to be influential in
blood vessel formation. After embryos were exposed
prematurely to the growth factor, a large number (in
comparison with either the DMEM or VEGF blood vessel counts)
of blood vessels formed.
Insufficient data from the
second experiment prevents any definite conclusions about
the role of bFGF on blood vessel formation within the CAM
membrane. However, the bFGF CAM membrane did exhibit more
blood vessels than either of the DMEM segements. The bFGF
membrane segment had a total of thirteen blood vessels,
whereas the DMEM segments had seven and twelve blood
vessels, respectively. In comparison to the bFGF blood
vessel count (13), the average of the DMEM filter square
blood vessels (7.5) was moderately lower.
The
first experiment showed a strong correlation between the
growth factor and increased blood vessel formation on the
CAM membrane of chick embryos. bFGF, produced in the CAM
membrane, is required for the process of vasculogenesis,
during which time hemangioblasts are specified and blood
vessels are created (Gilbert 2003). A greater concentration
of bFGF may cause more blood vessels to appear during
vasculogenesis. Within an area of high bFGF concentration,
more mesoderm cells may be specified to form hemangioblasts,
and more blood islands and vessels will be produced
(Gilbert, 2003). In addition, the importance of these growth
factors is demonstrated by mutant embryos that lack the
proper receptors for bFGF (and also VEGF), which have a
significantly lower chance of survival as vascular
development will not occur properly.
References:
Brooks, P.C., Montgomery, A.M., and
Cheresh, D.A. (1999) Methods Mol. Biol.
129:257-269.
Gilbert, Scott F.(2000) Developmental
Biology, 6th, Sunderland: Sinauer Associates, Inc.,
MA.
Gilbert, Scott. 2003. Developmental
Biology, 7th ed. Sinauer Associates, Inc., MA, pp. 501-505;
517.
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