title: Postconditioning attenuates renal ischemia-reperfusion injury by preventing DAF down-regulation.
abstract: OBJECTIVE
  There is increasing evidence that ischemic postconditioning may noticeably attenuate renal ischemic-reperfusion injury, although the specific mechanisms are not fully clear. We examined the role of the complement system, especially membrane bound complement regulatory proteins, in postconditioning after renal ischemic-reperfusion injury in a right nephrectomy rat model.
  
  
  METHODS
  After right nephrectomy the left renal pedicles were occluded for 60 minutes, followed by 24-hour reperfusion. Postconditioning was induced by 6 cycles of 10-second ischemia and 10-second reperfusion before reperfusion. After 24-hour reperfusion without a control blood samples were obtained via the vena cava. Renal samples were also obtained. DAF, CD46, CD59, C3aR and C5aR mRNA and protein expression was examined by reverse transcriptase-polymerase chain reaction, Western blot and immunohistochemistry. C3/C9 deposition in tissue was detected by immunofluorescence. Renal function, histology and cellular apoptosis were also observed.
  
  
  RESULTS
  In renal tissue postconditioning prevents DAF down-regulation, which is induced by ischemic-reperfusion injury. It results in the decreased renal necrosis caused by ischemic-reperfusion injury mediated complement activation. However, in all experimental groups renal CD46/CD59 expression was not altered. Increased DAF expression due to postconditioning may decrease C5aR expression in renal tissues compared with ischemic-reperfusion injury, which can decrease apoptosis. C3aR expression did not differ among the experimental groups.
  
  
  CONCLUSIONS
  These findings provide new evidence that postconditioning protects kidneys from ischemic-reperfusion injury, at least in part, by preventing DAF down-regulation.
authors.affiliation: Department of Pathology, West China Second University Hospital, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Tielong
authors.initials: T
authors.lastname: Tang
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Bu
mesh_terms: D000818:Animals; D018958:CD55 Antigens / Q000502:physiology*; D015536:Down-Regulation; D007668:Kidney / Q000098:blood supply*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000517:prevention & control*
chemical_list: D018958:CD55 Antigens