In this work we investigated the role of nitric oxide (NO) in the angiogenesis mediated by vascular endothelial growth factor (VEGF) during rat liver regeneration after two-thirds partial hepatectomy. Sham operated (Sh) and partially hepatectomized (PH) male Wistar rats were randomized in three experimental groups: control (treated with vehicle); pre-treated with sodium nitroprusside (SNP: 0.25 mg/kg body weight, i.v. at a rate of 1 ml/h) and pre-treated with the preferential iNOS inhibitor, aminoguanidine (AG, 100 mg/kg body weight, i.p.). Animals were killed at 5, 24 and 72 h after surgery. At 5 h post-surgery, NO production was estimated by EPR (Sh-Control: 37.65+/-10.70; PH-Control: 88.13+/-1.60(); Sh-SNP: 90.35+/-3.11(); PH-SNP: 119.5+/-12.10()(#); Sh-AG: 33.27+/-5.23, PH-AG: 36.80+/-3.40(#)) (p0.05 vs Sh-Control; (#)p0.05 vs PH-Control). At 24 h after PH, VEGF levels showed no difference between PH-Control and PH-SNP animals. However, after 72 h, VEGF protein levels in PH-SNP animals were found to be increased (above 300%) with respect to PH-Control. On the other hand, aminoguanidine (AG) pre-treatment blocked the rise of inhibition of NO generation and decreased VEGF expression. Our results demonstrated that NO plays a role in modulating VEGF protein expression after hepatectomy in rats.
