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Photoactivation of Vascular iNOS and Elevation of cGMP In Vivo: Possible Mechanism for Photovasorelaxation and Inhibition of Restenosis in an Atherosclerotic Rabbit Model ¶
Author(s) -
Kipshidze Nicholas,
Keelan Michael H.,
Petersen John R.,
Bachutashvili Ivan,
Vossoughi Jafar,
Karanian John,
Ghosh Chandramallika,
Iversen Patrick,
Roubin Gary S.,
Leon Martin B.,
Moses Jeffrey W.
Publication year - 2000
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2000)0720579poviae2.0.co2
Subject(s) - restenosis , cyclic guanosine monophosphate , balloon , in vivo , medicine , nitric oxide synthase , endocrinology , nitric oxide , chemistry , biology , stent , microbiology and biotechnology
Recently, intravascular low‐power red laser light (LPRLL) therapy has been proposed for the prevention of postangioplasty restenosis due to the observed inhibition of experimental neointimal formation. The objective of this study was to determine the impact of endoluminal LPRLL on vascular levels of inducible nitric oxide synthase (iNOS) and cyclic guanosine monophosphate (cGMP) to help define the mechanism of this effect. Eight atherosclerotic male adult New Zealand White rabbits weighing 4–6 kg were used in these studies. The iliac arteries were treated in separate zones with: (1) balloon inflation only; (2) laser illumination only; and (3) balloon inflation + laser illumination. An uninjured zone of the iliac artery served as a control. Laser irradiation (630 nm) was delivered to the vessel wall via a Cold ™ laser Illuminator (Cook, Inc., Bloomington, IN), with a 3 mm–diameter balloon. Experiments demonstrated that vascular cGMP levels obtained immediately following treatment in the balloon only group was the lowest (0.29 ± 0.05 pmol/mg protein) and significantly lower compared with the uninjured controls (1.01 ± 0.07 pmol/mg protein) ( P < 0.001). In the laser only treated group cGMP levels were significantly increased (2.87 ± 0.12 pmol/mg protein) compared with the uninjured control ( P < 0.001) and the balloon only group ( P < 0.001). Vascular cGMP levels in the balloon + laser group (2.09 ± 0.07 pmol/mg protein) was also increased compared to the balloon only ( P < 0.001) and control ( P < 0.001) groups. Qualitative analysis of Western blot demonstrated that laser illumination induces iNOS. In contrast balloon dilatation did not induce iNOS. Balloon + laser treatment, however, tended to restore the expression of iNOS. Our study demonstrated that intravascular low dose laser irradiation induces iNOS and elevates vascular cGMP in an in vivo atherosclerotic rabbit model.