The growth promoting effects of bFGF, PD-ECGF and VEGF on cultured postimplantation rat embryos deprived of serum fractions

Serum components in which embryos are cultured in vitro are very important for normal embryonic development. In this study, rat serum was fractionated using Macrosep filters to study the effect of a single growth factor. The fractionated serum, both that containing only material greater than 30 kDa molecular weight (> 30 kDa) and that from which material between 30 kDa and 50 kDa had been removed (< 30 kDa + > 50 kDa), caused significant embryoni c growth retardation. Addition of different concentrations of basic fibrobl ast growth factor (bFGF, 18 kDa), vascular endothelial growth factor (VEGF, 45 kDa) and platelet-derived endothelial growth factor (PD-ECGF, 45 kDa), to fractionated serum (bFGF to > 30 kDa serum and VEGF or PD-ECGF to < 30 k Da + > 50 kDa serum) partially restored embryonic growth and development ac cording to a morphological scoring system and protein assay. This restorati on was clear by all criteria, as well as in yolk sac vascularisation and he art development. The growth promoting effects of all 3 factors were signifi cant but did not reach the level seen in embryos grown in whole rat serum. The effect of these growth factors was also investigated on anembryonic yol k sac development using a concentration for which maximum whole embryonic g rowth was seen (128 ng/ml bFGF, 1.6 ng/ml VEGF and 4 ng/ml PD-ECGF), and si gnificant anembryonic yolk sac development was found. These findings sugges t that the angiogenic factors may have a growth promoting effect on total e mbryonic development and vascularisation.