Inhibitory effects of bortezomib on restenosis of rat experimental vein graft

Abstract

Objective The anti-inflammatory and vaso-protective effects of bortezomib were analyzed in rat model to test whether it inhibits neointima formation in transplant-induced vasculopathy.Methods Seventy-six rats were subjected to autologous vein grafting surgery.Thereafter,all post-surgical rats were randomly divided into two groups and dosed intravenously with 0.15 mg/kg bortezomib or vehicle on the day 0,3,7,and 10.After 24 and 72 h,rats were humanely killed and vein grafts were processed for real-time reverse transcription-polymerase chain reaction (RT-PCR) to test the gene expression of cytokineinduced neutrophil chemoattractant-2β (CINC-2β),monocyte chemoattractant protein ( MCP)-1,interleukin (IL)-1,IL-6 and tumor necrosis factor (TNF)-α.Meanwhile,24-h vein grafts were processed for enzyme linked immunosorbent assay ( ELISA ) or neutrophil chemotaxis assay.Subsequently,rats were euthanized at 4th week after grafting and samples were processed for morphometric analysis.Results The expression of mRNA for chemokines ( CINC-2β,MCP-1 ) and cytokines ( IL-1,IL-6 and TNF-α) were markedly increased in the injured vessels at the first day after surgery and declined during the following three days,and protein levels of them were markedly increased at the same time [ CINC-2β (415.23 ±56.50) pg/mg; MCP-1 (9894.58 ±2795.62) pg/mg; IL-1 (3087.51 ±609.19) pg/mg; IL-6 (2225.27±206.06) pg/mg; TNF-α (402.31 ± 134.13) pg/mg] (P ＜0.05) accompanied with a marked increase in neutrophil migration toward homogenates of injured vessels as chemotactic index (CI) was (241.52 ±33.43 ) ％ ( P ＜ 0.05 ).Morphometric analysis revealed that the intima of grafts was thickened markedly as (70.93 ± 11.25) μm at 4th week after surgery (P ＜0.05).It was important that bortezomib significantly attenuated gene expression and protein levels in most of the inflammatory mediators except IL-1 [ CINC-2β(231.48 ±36.32) pg/mg; MCP-1 (5846.10 ± 1044.33) pg/mg; IL-6 (1023.22 ± 109.84) pg/mg;TNF-α (218.40 ± 38.06) pg/mg] (P ＜ 0.05 ),and simultaneously inhibited neutrophil chemotactic activity of the vessel homogenates as CI was ( 167.81 ± 30.00) ％ (P ＜0.05 ).And notably,bortezomib resulted in significant inhibition of intimal hyperplasia as (35.23 ±5.21 ) μm at 4th week compared with untreated controls (P ＜ 0.05).Conclusion Bortezomib could inhibit neointima formation by attenuating the inflammatory response in transplant-induced vasculopathy. Key words: Proteasome inhibitor; Bypass graft; Intimal hyperplasia; Restenosis