Vascular Endothelial Growth Factor Protein Expression in a Renal Ablation Rabbit Model under Prolonged Warm and Cold Ischemia

Abstract

Background/Aims: To establish a potential correlation between renal and systemic production of vascular endothelial growth factor (VEGF) protein after prolonged ischemia in a renal ablation model under normothermic and hypothermic conditions. Methods: 38 uninephrectomized New Zealand rabbits were divided into 5 groups. The rabbits of each group underwent partial nephrectomy under 90 and 60 min of warm and 90 and 120 min of cold ischemia, except for the sham group (S), which served as control. Serum creatinine (SCr) and blood-urea-nitrogen (BUN) levels were assessed. On the 15th postoperative day (POD), the animals were euthanized and the remaining kidneys were evaluated. VEGF immunohistochemistry and serum Western blot analysis were performed. Results: In comparison to the control group, groups 60W, 90C and 120C showed 1.6-, 1.14- and 1.75-fold decreases, respectively, while the production of VEGF was significantly declined by 7.4-fold in group 90W (p < 0.05). Immunohistochemistry revealed prominent VEGF staining in the above-mentioned three groups, while in group 90W staining was negative. Serum biochemistry and microscopic evaluation verified the same differentiation. Conclusion: Renal and serum VEGF seem to have an analogous expression under conditions of prolonged ischemia. VEGF is overexpressed in hypothermic conditions compared to warm ischemia exceeding 60 min. Hypothermia can be more advantageous in a procedure applying prolonged ischemia.