Adverse effects of nitroglycerin treatment on endothelial function, vascular nitrotyrosine levels and cGMP-dependent protein kinase activity in hyperlipidemic Watanabe rabbits
Ascan Warnholtz, MD*,
Hanke Mollnau, MD*,
Thomas Heitzer, MD*,
Anatol Kontush, PhD ,
Tobias Möller-Bertram, BS*,
Dirk Lavall, BS*,
Adel Giaid, PhD ,
Ulrike Beisiegel, PhD,
Stefan L. Marklund, MD||,
Ulrich Walter, MD ,
Thomas Meinertz, MD* and
Thomas Munzel, MD*,*
* Division of Cardiology, University Hospital Eppendorf, Hamburg, Germany
Department of Medicine, University Hospital Eppendorf, Hamburg, Germany
Institut für Klinische Biochemie und Pathobiochemie, University of Würzburg, Würzburg, Germany
Department of Pathology, The Montreal General Hospital, McGill University, Quebec, Canada
|| Department of Medical Biosciences and Clinical Chemistry, Umea University Hospital, Umea, Sweden
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Figure 1 Effects of three days nitroglycerin (NTG) treatment on acetylcholine (ACh) (A) and NTG concentration-response curve (B). Data are expressed as mean ± SEM of 8 to 10 experiments. *p < 0.05 versus control, p < 0.05 versus WHHL. Black circles = control; black triangles = control + NTG; open circles = WHHL; open triangles = WHHL + NTG. WHHL = Watanabe heritable hyperlipidemic rabbits.
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Figure 2 Effect of three days nitroglycerin (NTG) treatment on vascular superoxide in aortas from New Zealand white rabbits (NZWR) and Watanabe heritable hyperlipidemic rabbits (WHHL) as detected with hydroethidine. Vessels were labeled with the dye hydroethidine, which produces a red fluorescence when oxidized to ethidium bromide by superoxide. Data are representative for n = 4 experiments. A = adventitia; E = endothelium; M = media.
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Figure 3 Effects of three days nitroglycerin (NTG) treatment on vascular superoxide production in aortas from control rabbits (C) and Watanabe heritable hyperlipidemic rabbits (WHHL) as estimated by lucigenin (250 and 5 µM) and CLA-enhanced chemiluminescence. The data are presented as mean ± SEM (n = 4 to 10 per group). *p < 0.05 versus control, p < 0.05 versus WHHL.
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Figure 4 Effects of three days nitroglycerin (NTG) treatment on immunoreactivity for nitrotyrosine in vessels from control rabbits without (A) and with nitroglycerin treatment (B) and hyperlipidemic animals without (C) and with NTG treatment (D). Please note that NTG treatment of hyperlipidemic animals caused a marked increase in nitrotyrosine staining in the endothelium and the subendothelial space (brown staining).
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Figure 5 Immunoreactivity for nitrotyrosine in vessels from control (C) and hyperlipidemic (WHHL) rabbits with and without nitroglycerin (NTG) treatment. Immunohistochemical grades were determined as described in methods. Data are presented as mean ± SEM from 4 to 6 experiments. *p < 0.05 versus control, p <0.05 versus WHHL.
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Figure 6 Effects of nitroglycerin (NTG) treatment on the expression of the cGMP dependent protein kinase (cGK-I) and the vasodilatory stimulated phosphoprotein (P-VASP) in NZWR and WHHL. A, upper panel shows original blots of aortas from NZWR and WHHL with and without NTG treatment. B, the lower panel shows the densitometric quantification. Data are presented as mean ± SEM from 4 experiments *p < 0.05 versus control. Abbreviations as in Figure 2.
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- and ß-carotene levels. Data are presented as mean ± SEM from 8 to 12 experiments. *p < 0.05 versus control.