Objective: To assess the effect of valsartan eluting-stents on restenosis and collagen deposition in neointima hyperplasia in rabbits.
Methods: Valsartan eluting-stents and the carrier eluting-stents were made with patented multi-layers coating techniques. Bare stents (n = 8), carrier eluting-stents (n = 8) and valsartan eluting-stents (n = 10) were implanted into rabbit abdominal aortas, respectively. Quantitive angiography (QA) was performed before, immediately post and 3 months after stents implantations to determine the diameter of aortas. Rabbits were killed 3 months post stents implantation and the cross sections of the stented vessels were analyzed for neointimal formation: luminal area (LA), neointimal area (NIA), inner elastic lumina area (IELA), the maximal inner-membrane thickness (MIT) and percent stenosis. MASSON and picrosirius red staining were performed to observe the collagen deposition in neointima analyzed.
Results: The mean aortic diameters measured by QA at different time points were similar between the groups. LA was significantly larger (5 016 269 microm(2) +/- 207,934 microm(2) vs. 4,345,548 microm(2) +/- 125,822 microm(2) and 4,302,061 microm(2) +/- 167,952 microm(2), P < 0.01 vs. valsartan stents) while NIA (441,577 microm(2) +/- 74,099 microm(2) vs. 1,119,635 microm(2) +/- 163,503 microm(2) and 1,135,636 microm(2) +/- 136,555 microm(2)) and MIT (116 microm +/- 12 microm vs. 240 microm +/- 30 microm and 192 microm +/- 21 microm) as well as percent stenosis (8% +/- 2% vs. 20% +/- 2% and 21% +/- 2%) were significantly reduced in valsartan eluting-stents group compared to bare and carrier stents groups. MASSON and picrosirius red staining revealed rich type III collagen deposition in neointima and spare type I collagen patched around stents struts in bare and carrier stents groups and collagen deposition was rarely seen in neointima and stents struts in valsartan eluting-stents group.
Conclusion: Valsartan eluting-stents inhibited neointimal hyperplasia by decreasing collagen deposition.