Evidence for a ceiling of cardioprotection with a @entity842 donor-induced delayed preconditioning in XXXX .

@entity5045 @entity16475 @entity63 @entity1563 @entity95 @entity1188 @entity842
Although extensive attention has been devoted to the window of preconditioning, only few studies investigated the efficacy of preconditioning against @entity63 with increasing durations. To date, a "ceiling of protection" has been demonstrated to occur with early preconditioning but nothing is known about delayed preconditioning. Accordingly, the efficacy of a @entity842 (NO)-donor-induced delayed preconditioning was tested against @entity63 insults of increasing duration. Accordingly, 65 @entity95 received a 75-min intravenous infusion of either saline (control group), or an NO-donor ( @entity16475 ) at 3 microg/kg/min (SNAP-3 group) or 30 microg/kg/min (SNAP-30 group). Twenty-four hours later, @entity95 randomly underwent either a 15-, 20-, or a 30-min @entity1563 ( @entity1563 ). @entity1188 size was assessed after 72-h reperfusion ( @entity5045 staining, percentage of the area at risk). After 15-min @entity1563 , both SNAP-3 and SNAP-30 reduced @entity1188 size compared with control (10 +/- 3, 5 +/- 1 versus 29 +/- 8%, respectively; p < 0.05). After 20-min @entity1563 , significant cardioprotection was only observed with SNAP-30 (29 +/- 4, 21 +/- 6 versus 36 +/- 2% for SNAP-3, SNAP-30 versus control, respectively). After 30-min @entity1563 , both SNAP-3 and SNAP-30 failed to reduce @entity1188 size (48 +/- 2, 50 +/- 5 versus 50 +/- 4% for SNAP-3, SNAP-30 versus control, respectively). In conclusion, this study demonstrates a dose-related ceiling of protection with delayed preconditioning induced by an NO donor. It supports that delayed preconditioning might exert its maximal beneficial effect with early reperfusion and this finding supports the necessary use of different durations of @entity63 when investigating cardioprotective strategies.
