Antisense oligonucleotides to c-fos and c-jun inhibit intimal thickening in a rat vein graft model

Background. C-fos and c-jun are 2 immediate early genes that have been impl icated in the stimulation of vascular smooth muscle cell proliferation and migration. In previous experiments in our laboratory with a rat vein graft model a 2- to 3-fold increase of messenger RNA of c-fos and c-jun were note d 1 hour after vein graft perfusion. Because c-fos and c-jun are up-regulat ed after the perfusion of vein grafts, the purpose of this study was to del ineate the temporal expression of c-fos and c-jun protein and to study the effect of antisense oligonucleotides (ASO) to c-fos and c-jun on intimal th ickening observed in this model. Methods. Sprague-Dawley rats underwent bilateral interposition femoral arte ry grafts with use of the superficial epigastric vein, which was harvested from 15 minutes up to 2 weeks and analyzed by Western blot for Fos and Jun protein. Additional rats underwent bypasses and at the time of the procedur e 1 graft was treated with a pluronic gel containing an ASO to c-fos, c-jun , or sense and the contralateral side was treated with pluronic gel only. T he vein grafts were harvested 2 weeks after the procedure and perfusion fix ed. After longitudinal sectioning, the intimal and total wall thicknesses w ere measured in the perianastomotic and midgraft regions by a morphometric digitizing microscope and the statistics were analyzed by a paired Student' s t test. Results. Protein analysis by Western blot showed that c-fos levels rose qui ckly within 2 hours and leveled at 6 hours 40-fold above basal levels after vein graft perfusion. Similarly, c-jun levels rose 10-fold above basal lev els after 15 minutes and peaked at 2 hours 120-fold above basal levels. The treatment of the vein grafts with these ASOs resulted in a reduction of ab out 30% in the thickness of the intimal layer and the total wall thickness in both the perianastomotic and the midgraft regions, which was statistical ly significant different from control veins. Conclusion. These results indicate a possible therapeutic role for ASO to i mmediate early genes in the treatment of vein graft intimal hyperplasia.