title: Macrophages contribute to the initiation of ischaemic acute renal failure in rats.
abstract: BACKGROUND
  Although neutrophils and T cells are important in mediating renal injury following ischaemia/reperfusion, the role of macrophages is still unknown. Using liposomal clodronate (LC), we investigated the effect of systemic monocyte-macrophage depletion on renal damage in ischaemic acute renal failure in rats.
  
  
  METHODS
  Male Sprague-Dawley rats were injected by LC or liposomal vehicle and underwent bilateral renal pedicle clamping (40 min) or sham ischaemia. Biochemical and histological renal damage was assessed and gene expression kinetics of tumour necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6 and monocyte chemoattractant protein-1 (MCP-1) using quantitative real-time reverse transcription-polymerase chain reaction were conducted at 4, 24 and 72 h after reperfusion.
  
  
  RESULTS
  The percentage of peripheral blood monocytes and ectodysplasin-1-positive cells in liver decreased significantly in LC-treated animals at 24 h. Systemic monocyte-macrophage depletion resulted in (a) less severe tubular necrosis, (b) reduced inflammation and (c) reduced apoptosis of renal tubular epithelial cells. Gene expression kinetics showed that IL-6 gene expression peaked early at 4 h after reperfusion, followed by TNF-alpha, IL-1beta and MCP-1 expressions, which peaked at 24 h. Systemic monocyte-macrophage depletion significantly reduced these cytokine and chemokine gene expressions.
  
  
  CONCLUSIONS
  These results suggest that macrophages are an important mediator in the initiation period of ischaemia/reperfusion injury and strategies that limit initial macrophage infiltration or activation can be useful in the treatment of acute renal failure.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Korea University Hospital, Anam-Dong, Sungbuk-Ku, Seoul 136-705, Korea.
authors.forename: Sang-Kyung
authors.initials: SK
authors.lastname: Jo
authors.forename: Su-Ah
authors.initials: SA
authors.lastname: Sung
authors.forename: Won-Yong
authors.initials: WY
authors.lastname: Cho
authors.forename: Kang-Jee
authors.initials: KJ
authors.lastname: Go
authors.forename: Hyoung-Kyu
authors.initials: HK
authors.lastname: Kim
mesh_terms: D058186:Acute Kidney Injury / Q000473:pathology* / Q000503:physiopathology; D000818:Animals; D017209:Apoptosis; D001707:Biopsy, Needle; D049109:Cell Proliferation; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007375:Interleukin-1 / Q000032:analysis / Q000378:metabolism; D015850:Interleukin-6 / Q000032:analysis / Q000378:metabolism; D007677:Kidney Function Tests; D008264:Macrophages / Q000166:cytology* / Q000502:physiology; D008297:Male; D011336:Probability; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D015427:Reperfusion Injury / Q000473:pathology* / Q000503:physiopathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000378:metabolism
chemical_list: D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha