The upper panel shows the effect of the 100?M concentration of each drug. and reperfusion is derived, at least in part, from cyclo-oxygenase-2. Cyclo-oxygenase-2 plays an important protective role in a setting of ischaemia-reperfusion of the heart. the nitric oxide generated by this compound (Rossoni perfused rabbit heart model. We have compared the effects of exposure of the heart, prior to the period of ischaemia, to a number of drugs with varying degrees of selectivity for COX-2. For comparison, we have also assessed the effects of exposure of the heart to the nitric oxide-releasing aspirin derivative, NCX-4016. Methods The experimental procedures were approved by the Animal Care Committees of the University or college of Milan and the University or college of Calgary and the studies were performed in accordance with the principles set forth in the Italian and Canadian guidelines for the care and use of laboratory animals. Ischaemia-reperfusion in isolated rabbit heart Male, New Zealand White SAR125844 rabbits (BMG-Allevamento, Cividate al Piano, BG, Italy or Reimans Fur Ranches, Calgary, AB, Canada) weighing 2.0?C?2.2?kg were utilized for these experiments. The hearts were excized and perfused retrogradely at 37C SAR125844 through the aorta as previously explained by Berti value) of less than 5% was considered significant. In all furniture and figures, results are expressed as means.e.mean. Area under the curve (AUC) was estimated according to the trapezoid method (Microcal Software Inc., Northampton, MA, U.S.A.). Materials NCX-4016 was obtained from NicOx S.A. (Sophia Antipolis, France), celecoxib from Monsanto (St. Louis, MO, U.S.A.), DuP-697 from DuPont-Merck (Dover, DE, U.S.A.), aspirin from Sigma Chemical Co. (St. Louis, MO, U.S.A.) and meloxicam from Boehringer-Ingelheim (Danbury, CT, U.S.A.). The ELISA packages for determination of 6-keto-PGF1 and thromboxane B2 were obtained from Amersham Italia (Milan, Italy) and Medicorp (Montreal, Canada), respectively. The packages for Rabbit Polyclonal to FCGR2A creatine kinase determination were obtained from Boehringer-Mannheim (Milan, Italy). NCX-4016 and aspirin were in the beginning dissolved in dimethylsulphoxide, then diluted in Krebs Henseleit answer (final concentration of dimethylsulphoxide was 1%). All other drugs were dissolved directly in the Krebs Henseleit answer. Results Effects of ischaemia-reperfusion The reduction of the perfusion flow-rate of electrically paced isovolumic left heart preparations for 40?min resulted in a progressive increase in left ventricular SAR125844 end diastolic pressure (Physique 1). During reperfusion, left ventricular developed pressure was significantly reduced (Physique 2) and coronary perfusion pressure (CPP) increased consistently above baseline (Physique 3). Moreover, there was a marked increase in creatine kinase (CK) activity in the cardiac perfusates during the reperfusion period, reaching a maximum at 45?C?50?min of the reperfusion (Physique 4). In the pre-ischaemic period, 6-keto PGF1 was detectable in the perfusates (mean release of 2.70.2?ng?min?1). During the first 10?min of the reperfusion period, the release of 6-keto PGF1 increased approximately 3 fold (mean release of 8.70.8?ng?min?1). Open in a separate window Physique 1 Effect of cyclo-oxygenase inhibitors on left ventricular end-diastolic pressure (LVEDP) in paced isovolumic left heart preparations subjected to low-flow ischaemia (1?ml?min?1 for 40?min) and reperfusion (20?ml?min?1 for 20?min). The compounds were infused for 20?min before reduction of flow. The upper panel shows the effect of the 100?M concentration of each drug. The lower panel shows the area-under-the-curve (AUC) for all those three concentrations of each test drug. * em P /em 0.05, ** em P /em 0.01, *** em P /em 0.001 versus the vehicle-treated group. Each point/bar represents the means.e.mean of 6?C?10 experiments. Open in a separate window Physique SAR125844 2 Effect of cyclo-oxygenase inhibitors on left ventricular developed pressure (LVDP) in paced isovolumic left heart preparations subjected to low-flow ischaemia (1?ml?min?1 for 40?min) and reperfusion (20?ml?min?1 for 20?min). The compounds were infused for 20?min before reduction of flow The upper panel shows the effect of the 100?M concentration of each drug. The lower panel shows the area-under-the-curve (AUC) during the reperfusion period for all those three concentrations of each test drug. * em P /em 0.05, ** em P /em 0.01, *** em P /em 0.001 versus the vehicle-treated group. Each point/bar represents the mean (s.e.mean in the lower panel) of 6?C?10 experiments. Open in a separate window Physique 3 Effect of cyclo-oxygenase inhibitors on coronary perfusion pressure (CPP) in paced isovolumic heart preparations subjected.