Ribozyme-mediated inhibition of rat leukocyte-type 12-lipoxygenase prevents intimal hyperplasia in balloon-injured rat carotid arteries.
BACKGROUND
12-Lipoxygenase (12-LO) products of arachidonate metabolism have growth and chemotactic effects in vascular smooth muscle cells. We have also recently demonstrated increased 12-LO mRNA and protein expression in the neointima of balloon-injured rat carotid arteries. In this study, we evaluated whether 12-LO activation plays a role in neointimal thickening in this rat model by using a specific ribozyme (Rz) directed to rat 12-LO.


RESULTS
We designed a chimeric DNA-RNA hammerhead Rz to cleave rat leukocyte-type 12-LO mRNA. This Rz dose-dependently cleaved a 166-nucleotide target 12-LO mRNA substrate in vitro and reduced 12-LO mRNA and protein expression in rat vascular smooth muscle cells. A control mutant Rz (MRz) with a point mutation in the catalytic site was inactive. To test the in vivo efficacy of the 12-LO Rz, the left common carotid arteries of rats were injured with a balloon catheter. The distal half of the injured arteries was treated with Rz or MRz mixed with lipofectin. The proximal half received only lipofectin. Twelve days after injury, intima-to-media ratios were significantly lower in the Rz-treated sections than in untreated sections from the same rat (0.742+/-0.16 versus 1.749+/-0.12, P:<0.001). In contrast, the MRz had no significant effect.


CONCLUSIONS
These results indicate the important role of the leukocyte-type 12-LO pathway in restenosis in response to injury.
Gu
J L
JL
Division of Endocrinology and Metabolism, University of Virginia Health Science Center, Charlottesville, VA, 22908, USA.
Pei
H
H
Thomas
L
L
Nadler
J L
JL
Rossi
J J
JJ
Lanting
L
L
Natarajan
R
R
D000704:Analysis of Variance; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects; D000818:Animals; D001092:Arachidonate 12-Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D002340:Carotid Artery Diseases / Q000209:etiology / Q000517:prevention & control*; D002465:Cell Movement / Q000187:drug effects; D003287:Contrast Media / Q000378:metabolism; D004195:Disease Models, Animal; D005353:Fibronectins / Q000378:metabolism; D019793:Fluorescein / Q000378:metabolism; D006965:Hyperplasia / Q000209:etiology / Q000517:prevention & control; D007962:Leukocytes / Q000201:enzymology*; D016859:Lipoxygenase Inhibitors; D008297:Male; D016337:RNA, Catalytic / Q000235:genetics / Q000378:metabolism / Q000627:therapeutic use*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection; D017539:Tunica Intima / Q000473:pathology*
D003287:Contrast Media; D005353:Fibronectins; D016859:Lipoxygenase Inhibitors; D016337:RNA, Catalytic; D012333:RNA, Messenger; D001092:Arachidonate 12-Lipoxygenase; D019793:Fluorescein