Vascular endothelial growth factor- and platelet-derived growth factor-angiogenesis depressed but fetal bovine serum-angiogenesis enhanced choroidal tissue cultures of streptozotocin-diabetic wistar and GK rats

Background: Diabetic state-induced alterations of angiogenic activity of va scular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) were compared with that of fetal bovine serum (FBS) in the cultured choroidal explants of streptozotocin (STZ)-diabetic Wistar and diabetic GK rats, Methods: Choroidal explants (0.04-1.0 mm(2)) were isolated from rat eyeball s and cultured in fibrin gels with FBS-Dulbecco's modified Eagle's medium ( 0.5 mL) containing antibiotics and 300 mu g/mL epsilon-amino caproic acid i n the presence of recombinant mouse vascular endothelial growth factor and recombinant human platelet-derived growth factor BE at 37 degrees C under 5 % CO2 and 95% air, Microvessels newly budded from these choroidal explants were photographed, The number and length of all microvessels per choroidal explant were counted and measured as indices of angiogenesis in vitro. Results: Fetal bovine serum (5-10%) enhanced both angiogenic indices in the explants of STZ-diabetic Wistar and GK rats. The actions of the serum on b oth angiogenic indices in both diabetic rats were greater than those in age -matched normal rats. Vascular endothelial growth factor (3-30 ng/mL) with 1% fetal bovine serum increased the angiogenic indices in diabetic choroids , but was less pronounced than in normal choroids, The action of the growth factor (2.5 ng/mL) on angiogenesis was also less in diabetic choroids, Conclusions: Results suggest that the diabetic state may down-regulate the receptors for vascular endothelial and platelet-derived growth factors and/ or desensitize their postreceptor signaling in the vascular endothelial cel ls of choroids, being inexplicable for the enhanced actions of fetal bovine serum on angiogenesis in diabetic choroids.