title: Factors influencing rat survival in a warm renal ischemia model: time to adapt the protocols.
abstract: BACKGROUND
  Survival in warm renal ischemia models is not only dependent on the treatment or surgical technique being evaluated, but also on factors inherent to the model itself. Use of rats of various strains in previous studies makes interstudy comparison difficult when trying to design an appropriate model control that would yield intermediate survival. In this study, impact of rat strain on survival after prolonged warm renal ischemia in the setting of delivery-controlled inhalational anesthesia was evaluated.
  
  
  METHODS
  Under general delivery-controlled inhalation anesthesia with isoflurane, Dahl salt-sensitive, Wistar-Furth, Sprague-Dawley, and spontaneously hypertensive rats (n = 66 rats) were subjected to 150 minutes of unilateral renal warm ischemia time, subsequent reperfusion, and contralateral nephrectomy. Animals were followed up for 1 month, after which survivors were euthanized and morphologic changes in kidneys were scored.
  
  
  RESULTS
  Thirty-day survival was: Dahl salt sensitive, 78%; Wistar-Furth, 67%; Sprague-Dawley, 55%; and spontaneously hypertensive rats, 0% (P < .0001). Histologic acute injury scores were higher for non-survivors versus 30-day survivors (P < .0001).
  
  
  CONCLUSIONS
  Our data strongly suggest that rat strain is a major factor influencing survival and that strain and warm ischemia time selections must be considered together when designing a model control yielding intermediate survival. Further study is warranted in order to compare the effect of delivery-controlled inhalational versus historical anesthesia methods on animal survival.
authors.affiliation: Center for Biophotonics, University of California, Davis, Davis, California 95817, USA.
authors.forename: R N
authors.initials: RN
authors.lastname: Raman
authors.forename: C D
authors.initials: CD
authors.lastname: Pivetti
authors.forename: R
authors.initials: R
authors.lastname: Ramsamooj
authors.forename: D L
authors.initials: DL
authors.lastname: Matthews
authors.forename: S G
authors.initials: SG
authors.lastname: Demos
authors.forename: C
authors.initials: C
authors.lastname: Troppmann
mesh_terms: D000818:Animals; D007511:Ischemia / Q000503:physiopathology*; D007668:Kidney / Q000098:blood supply*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016019:Survival Analysis