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Alteration of aortic function from streptozotocin-diabetic rats with Kilham's virus is associated with inducible nitric oxide synthase

Nangle, M.R., Cotter, M.A., Cameron, N.E.
Veterinary journal 2006 v.172 no.3 pp. 455-459
veterinary medicine, aorta, rats, animal models, laboratory animals, viral diseases of animals and humans, diabetes, Kilham rat virus, streptozotocin, nitric oxide synthase, acetylcholine, endothelium
Kilham's rat virus (KRV) is a parvovirus commonly known to affect laboratory rats. Qualitative immunohistochemical analysis revealed that aorta isolated from KRV-infected streptozotocin (STZ)-induced diabetic adult rats expressed markedly greater levels of inducible nitric oxide synthase (iNOS) than aorta from KRV-infected controls. In contrast with the prevailing literature, nitric oxide-mediated endothelium-dependent relaxation to acetylcholine was not blunted by STZ-diabetes, but was comparable to relaxations of aorta from controls. However, with increasing ex vivo duration, a decreased response to acetylcholine was observed in the STZ-diabetic aorta. In addition, whereas contraction responses to phenylephrine were not significantly altered over time in control tissue, aorta from STZ-diabetic rats developed increased tensions. The data suggest that increased iNOS-derived nitric oxide masks expected acetylcholine-mediated relaxation deficits as a result of KRV-infection, and that the deficit is unmasked by iNOS turnover ex vivo.