Response Of Normal And Atherosclerotic Aortic Strips To Polymorphonuclear Leukocytes (PMNs) Products From Normal And Cholesterol-Fed Rabbits
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The aim of the present study was to examine the effect of PMNs products, from control (CTL) and from 8-weeks (8 WK) cholesterol-fed rabbits, on isolated normal and atherosclerotic aortic strips with and without endothelium. Hypercholesterolemia was induced by feeding rabbits I% cholesterol for 8 weeks. Isolation of rabbit PMNs was done from CTL and 8WK cholesterol-fed rabbits. Plasma cholesterol level was significantly elevated in 8WK rabbits, and this was accompanied by significant development of atherosclerotic lesions in aortic arch and abdominal aorta_ In organ bath chambers, cu. and 8WIC PMNs products caused contraction of precontracted normal and atherosclerotic aortic strips with intact endothelium This contraction was significantly increased with 8WK PMNs products. However, the contractile response of atherosclerotic strips was significantly less than that of control strips. Moreover, CTL PMNs products had no effect on precontracted aortic strips without endothelium, resting tension of aortic strips with and without endothelium. However, endothelium removal did not prevent but attenuated the contraction caused by 8 WK PMNs products on precontracted aortic strips or their resting tension. In addition, it was t;)ti rid that ACh-induced relaxation of precontracted aortic strips was i'nilicantly impaired in atherosclerotic strips compared to control -1,es When 8WK PMNs products were added, ACh-induced relaxation . significantly attenuated in both types of strips. In conclusion, PM Ns products-induced contraction was endothelium-dependent. I loNse‘er, hypercholesterolemia provided an endothelium-independent component to that contraction.