INFLUENCES OF DIETARY OMEGA-3 POLYUNSATURATED FATTY-ACIDS ON THE RECOVERY OF CARDIAC AND RENAL FUNCTIONS AFTER PRESERVATION IN HYPERLIPIDEMIC RATS

Background. The effects of a soybean oil diet and a high-cholesterol o il (HC) diet, and an HC diet with eicosapentaenoic acid (EPA) or docos ahexaenoic acid (DHA) supplementation, on basal and postpreservative c ardiac function of the hearts and on postpreservative renal function o f the kidneys from older rats were examined, Methods. Groups 1 through 4 of 100-week-old rats were fed either soybean oil, HC, HC with EPA, or HC with DKA, respectively, for 12 weeks, Blood was collected for an alysis of plasma fatty acids, and the heart and left kidney were remov ed hom the rat, In experiment 1, the heart was perfused on a Langendor ff apparatus, After evaluation of the cardiac function of each rat, th e heart was stored in histidine-tryptophanketoglutarate solution for 8 hr at 4 degrees C. The heart was reperfused and the recovery of cardi ac function was evaluated, The coronary perfusate during reperfusion w as collected to measure 6-keto prostaglandin F1 alpha and thromboxane B-2. Coronary flow (CF) perfused with Krebs-Henseleit bicarbonate (KHB ) solution containing B-hydroxytryptamine (5-HT) and nitroglycerin wer e evaluated in the Langendorff mode with atrial pacing (330 beats/min) , In experiment 2, the excised left kidney was immediately flushed and preserved with University of Wisconsin solution for 8 hr at 4 degrees C, The kidney was then reperfused with KHB solution and renal functio n was evaluated, Results. The plasma and cardiac EPA levels in group 3 were significantly higher than the levels found in the other groups, The plasma and cardiac ratios of EPA to arachidonic acid were signific antly higher in groups 3 and 4 than in groups 1 and 2, There were no s ignificant differences in basal cardiac function among any of the diet -fed rats, The percentage values of the recovery of aortic flow, cardi ac output (GO), and left ventricular max dp/dt in group 3 and CO in gr oup 4 were significantly higher than in group 2, In addition, the reco very of CF in group 3 tended to be higher than in group 2 (P=0.07), Th e percentage values of the recovery of aortic flow, CF, CO, and left v entricular max dp/dt in group I were significantly lower than in the o ther dietary groups, CF reperfused with KHB solution containing 5-HT w as significantly higher in group 3 than in groups 1 and 2, CF reperfus ed with KHB solution containing 5-HT was significantly higher in group 4 than in group 1, CF reperfused with IMB solution containing nitrogl ycerin in group 3 tended to be higher than in groups 1 and 2 (P=0.07), The thromboxame B-2 concentrations in the coronary perfusate during r eperfusion in groups 3 and 4 were significantly lower than in groups 1 and 2. Fractional sodium reabsorption in group 3 was significantly hi gher than in group 2, Inulin clearance in groups 3 and 4 was significa ntly higher than in group 1, The postpreservative urinary flow in grou p 3 was significantly higher than in groups 1 and 2, The urinary flow was significantly higher in group 4 than in group 1. Conclusions. Thes e results suggest that EPA administration may attenuate preservation a nd reperfusion injury and improve the recovery of cardiac and renal fu nctions in hyperlipidemic and older rats. DHA administration may also show beneficial effects on kidney preservation in hyperlipidemic rats.