title: [Pretreatment of isolated vein with rapamycin nanoparticles inhibits vein graft stenosis in rabbits].
abstract: OBJECTIVE
  To explore the effects of pretreatment of carbopol-encapsulated rapamycin-loaded nanoparticles (RPM-NP) on vein graft stenosis in a rabbit vein graft model.
  
  
  METHODS
  A segment of common carotid artery was replaced with a segment of external jugular vein in 40 rabbits. They were separated into four treatment groups, i.e. Group A: vein grafts were pretreated with intraluminal RPM-NP perfusion; Group B: peripheral venous veins were injected with RPM-NP; Group C: vein grafts received an equivalent perfusion of empty vehicle; Group D: vein grafts received no treatment. At Day 28 post-operation, the grafts and normal veins were harvested for histological examinations to analyze the indicators of intimal thickness, internal diameter, intimal/media thickness ratio and collagen volume index.
  
  
  RESULTS
  At Day 28 post-operation, the intimal/media thickness ratios were 0.26 ± 0.02, 0.73 ± 0.05, 0.71 ± 0.04, 0.69 ± 0.03 and 0.24 ± 0.01 in Groups A, B, C and D and the normal vein; the collagen volume index 0.24 ± 0.03, 0.56 ± 0.06, 0.53 ± 0.07, 0.49 ± 0.08 and 0.21 ± 0.01 respectively. Compared with the normal veins, the pathological indicators of vein graft intimal thickness, internal diameter, intimal/media thickness ratio and collagen volume index had significant differences in Groups B, C and D (all P < 0.05). But there were no significant differences among 3 groups (all P > 0.05). Compared with the normal vein, the parameters of vein graft intimal thickness, internal diameter, intimal/media thickness ratio and collagen volume index had no significant difference in Group A (all P > 0.05). But as compared with other groups, these indicators had statistical significant difference in Group A (all P < 0.05).
  
  
  CONCLUSIONS
  The local pretreatment of isolated vein with rapamycin nanoparticles may inhibit neointimal hyperplasia and prevent effectively vein graft stenosis.
authors.affiliation: Department of Cardiovascular Surgery, Qilu Hospital of Shandong University, Jinan, China.
authors.forename: Xing-jun
authors.initials: XJ
authors.lastname: Gong
authors.forename: Guang-qing
authors.initials: GQ
authors.lastname: Cao
authors.forename: Xi-quan
authors.initials: XQ
authors.lastname: Zhang
authors.forename: Shu-ming
authors.initials: SM
authors.lastname: Wu
authors.forename: Gong
authors.initials: G
authors.lastname: Zhang
authors.forename: Yue-hua
authors.initials: YH
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Zhou
mesh_terms: D000818:Animals; D017536:Carotid Artery, Common / Q000187:drug effects; D003251:Constriction, Pathologic / Q000517:prevention & control; D004730:Endothelium, Vascular / Q000187:drug effects; D005260:Female; D006083:Graft Occlusion, Vascular / Q000517:prevention & control*; D008297:Male; D053758:Nanoparticles; D011817:Rabbits; D020123:Sirolimus / Q000494:pharmacology*; D014680:Veins / Q000187:drug effects* / Q000637:transplantation*
chemical_list: D020123:Sirolimus