| Background and Objective Percutaneous transluming angioplasty(PTA) and stent implanting are effective management of artery stenosis,however, restenosis in 30-50% of PTA patients become the exigent problem in clinic.The pathogenesis of the restenosis concludes thrombus formation and neointimal hyperplasia in early time and the artery remodeling later, hi this process,restrictive remodeling caused by the fibroblasts in adventitia ,which proliferate, differentiate into myofibroblasts and synthesize collagen is the key factor. The aim of this present study is to examine the effect of pentoxifylline(PTX) on stenosis after balloon overstrech injury of rabbit iliac arteries,and explore the likely mechanism.Methods and Material Seventy-five adult male rabbits were divided into three groups at random:(l)Sham group(n=15); (2)balloon group(n=30).'received balloon injury only;(3)PTX group(n=30):were intraperitoneal irrigated of PTX from 1 day before injury at a dose of 42mg/kg till the animals being harvested, hi each group ,the animalswere divided into three teams randomly,and were harvested 1 week,4 weeks or 12 weeks later.All the animals were mensuarated the plasma fibrinogen concentration before operation and being killed. The iliac arteries were analyzed by cross-sectional morphometry and calculated the lumen area(LA) and total vessel area(EEL :area circumscribed by the external elastic lamina) as the measure of stenosis and constritive remodeling.Proliferating cell nuclear antigen(PCNA) and a -smooth muscle actin( a -SMA) were determined by high-SABC immunostain for evaluating cell proliferation and phenotype change.we also examined the mean greym of collagen within the vessel wall by Van Gieson stain to look into collagen distributing and producing.Result (l)Vessel morphometry:Both the balloon group and PTX group ,the internal exlastic lamina of the iliac arteries were ruptured after the operation. The neointima was thicken. The LA declined.But comparing with the balloon group the LA of PTX group was increased by 27% (1.12?.22mm2 vs. 0.88?.19 mm2 at week 4; P<0.05) and 58% ( 0.95 ?0.27mm2 vs. 0.60 ?0.14mm2 at week 12; P < 0.01)respectively ,the EEL were also separately magnifyed meanly about 25% (2.15 ?.31mm2 vs. 1.720.30mm2 at week 4; P>0.05) and 51% (1.91?.28mm2 vs. 1.270.34mm2 at week 12; P<0.01). r4w and ri2W mean the coefficients of correlation between LA and EEL . r4w was 0.48 and ri2wwas 0.85, compared r4w with ri2W;P<0.05o(2) Cell proliferation:There were many PCNA-positive cells within adventitia and neointimia at week l.The proliferation index(PI) in adventitia of PTX group were 0.67 ?0.05, however,that of balloon group was 0.95 + 0.03 , P<0.0l.The PI of neointimia in two group were 0.98 ?.02 and 0.76?.11, P<0.01.At week 4,the positive-cells within adventitia dismissed,but the mean PI in neointiamia of balloon group and PTX group were 0.04 + 0.02 and 0.10 + 0.04, /><0.05.The vessel wall without positive cell was at week 12 after operation.(3) Cell differenciation:the rate of a -SMA-positive cell in adventitia of PTX group was 67% lower than that of balloon group at week 1 (0.18 ?.07 vs. 0.350.10;/><0.01).The a - SMA-positive cells in neointima were increasing. The rate of PTX group was about 18% lower than balloon group(0.55 0.14 vs. 0.73 ?.15; P<0.01).(4) Collagen hyperplasia:The collagen fiber of balloon group was ruptured and disordered. The situation was improved by PTX. The collagen greym of adventitia in two groups was prominently different(25.46?.68 vs. 21.40 + 3.46 at week 4;/><0.05 and 34.06?.81 vs. 24.97 + 2.69 at week 12; /7<0.01).The mean collagen greym in neointima was lower than the balloon group at each time (7.31 + 3.50 vs. 9.86?.82atweek4; P<0.05 and 34.06?.81 vs. 24.87+2.69 at week 12; /><0.01).(5) Plasma fibrinogen concentration:The level of sham group hadno significant change,but it rose both in PTX group and balloon group after balloon injury prominently.At week l,the level was raised about 0.670.19umol/L in balloon gr...
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