Ischaemia-reperfusion injury in the rat kidney: the effect of preconditioning.
OBJECTIVE
To design and establish a model to examine whether brief periods of renal artery occlusion (ischaemic preconditioning, IP) confers protection from the effects of a subsequent period of ischaemia and reperfusion of the rat kidney.


METHODS
Ninety rats were randomized into six groups, i.e. sham-operated controls; IP alone; a 20 or 40 min period of left renal ischaemia (RI) alone; and IP followed by a 20 or 40 min period of RI. Preconditioning involved the sequential clamping of the left renal artery for 4 min and its release for 11 min, a total of four times, a 'critical interval' of 30 min before the ischaemic insult. Left renal tissue integrity was determined by dimercapto-succinic acid (DMSA) radionuclide imaging on a gamma-camera both immediately (day 0) and 2 and 9 days later. Acute tubular necrosis was also assessed histologically.


RESULTS
RI for 20 min resulted in a significant decrease in left renal tissue integrity on day 2 only (P < 0.001), whereas RI for 40 min caused significant left renal dysfunction on day 0, day 2 and day 9 (P < or = 0.01). For a given duration of ischaemia, there was no significant difference between results from (IP + RI) rats compared with RI-only rats at any of the three times. There was no significant alteration in renal tissue integrity in the IP-only rats compared with sham-operated controls. Histological findings paralleled the data obtained from DMSA uptake.


CONCLUSIONS
The IP regimen and 30 min 'critical interval' confers no protection to the kidney from a 20 or 40 min ischaemic episode. The IP regimen itself appears to have no effect, confirming the validity of our experimental model.
Islam
C F
CF
Department of Surgery, Royal Postgraduate Medical School, London, UK.
Mathie
R T
RT
Dinneen
M D
MD
Kiely
E A
EA
Peters
A M
AM
Grace
P A
PA
D000818:Animals; D003250:Constriction; D004195:Disease Models, Animal; D005260:Female; D019194:Ischemic Preconditioning; D007668:Kidney / Q000098:blood supply*; D007683:Kidney Tubular Necrosis, Acute / Q000000981:diagnostic imaging / Q000209:etiology; D015609:Organotechnetium Compounds; D011859:Radiography; D011877:Radionuclide Imaging; D051381:Rats; D017208:Rats, Wistar; D012077:Renal Artery; D015427:Reperfusion Injury / Q000000981:diagnostic imaging / Q000517:prevention & control*; D004113:Succimer; D019783:Technetium Tc 99m Dimercaptosuccinic Acid
D015609:Organotechnetium Compounds; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D004113:Succimer