title: Divergence of renal vascular endothelial growth factor mRNA expression and protein level in post-ischaemic rat kidneys.
abstract: Vascular endothelial growth factor (VEGF) is a potent regulator of angiogenesis and vascular protection. Synthesis of VEGF is induced by hypoxia and different cytokines including interleukin-6 (IL-6) and interleukin-1beta (IL-1beta). However, post-ischaemic alterations of this growth factor in the kidney are incompletely known. To determine VEGF synthesis in renal ischaemia/reperfusion (I/R) injury unilateral warm ischaemia was induced by cross-clamping the left renal pedicle for 55 min followed by 2 and 24 h of reperfusion (T2 and T24 kidneys; n= 6 in each group). Sham-operated, non-clamped animals served as controls (n= 6). Renal VEGF, IL-6 and IL-1beta mRNA expression were determined by reverse transcription-polymerase chain reaction (RT-PCR). VEGF protein level and distribution were determined by Western blot and immunohistochemical analysis. Immunohistochemistry revealed prominent VEGF staining in the outer medulla of control, T2 and T24 kidneys. VEGF immunoreactivity accumulated at the basolateral area of tubular epithelial cells in T2 kidneys, while it was diffuse in control and T24 kidneys. VEGF protein levels were increased 2- to 3-fold in T2 and T24 kidneys (both P < 0.01 versus controls), while VEGF mRNA expression remained unchanged. IL-6 mRNA expression was increased (P < 0.01 versus controls) in T2 kidneys, while IL-1beta mRNA expression remained unchanged. Increased VEGF protein levels but not mRNA expression suggests that during renal I/R injury VEGF synthesis in kidneys--unlike in other organs--is primarily regulated at a post-transcriptional level. As IL-6 mRNA expression increased simultaneously with VEGF protein levels, the post-ischaemic regulation of IL-6 and VEGF synthesis might be interrelated in rat kidney.
authors.affiliation: Research Group for Paediatrics and Nephrology, Hungarian Academy of Sciences, Budapest, Hungary. vannay@gyer1.sote.hu
authors.forename: Adám
authors.initials: A
authors.lastname: Vannay
authors.forename: Andrea
authors.initials: A
authors.lastname: Fekete
authors.forename: Csaba
authors.initials: C
authors.lastname: Adori
authors.forename: Tibor
authors.initials: T
authors.lastname: Tóth
authors.forename: György
authors.initials: G
authors.lastname: Losonczy
authors.forename: Lajos
authors.initials: L
authors.lastname: László
authors.forename: Barna
authors.initials: B
authors.lastname: Vásárhelyi
authors.forename: Tivadar
authors.initials: T
authors.lastname: Tulassay
authors.forename: András
authors.initials: A
authors.lastname: Szabó
mesh_terms: D058186:Acute Kidney Injury / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D007150:Immunohistochemistry; D007375:Interleukin-1 / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D007668:Kidney / Q000098:blood supply / Q000473:pathology / Q000502:physiology; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D012079:Renal Circulation / Q000502:physiology*; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism*
chemical_list: D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A