| With the increasing incidence and mortality of artherosclerosis(AS),percutaneous coronary stent implantation is a major breakthrough of treatment history and has becoming a routine therapy of AS.About 20% rates of in-stent restenosis(ISR)within 3 months after stent intervention can lead to the occurrence of other adverse cardiovascular events.The widespread use of drug-eluting stents(DES)decreases the rates of ISR,but 10% to 20% ISR rate still a major factor of limiting the clinical outcome after DES implantation.The drugs carried by DES are mainly paclitaxel and rapamycin,both of which prevent ISR by inhibiting hyperproliferation of smooth muscle cell(SMC).However,whether these two drugs affect the SMC's function by inducing an inflammatory response at the site of stent and leading to ISR formation is unclear.In this study,human arterial smooth muscle cell(HA-VSMC)was used as a cell model to evaluate whether DES-coated drugs influencing SMC's function by cell biology,ELISA and real-time fluorescence quantitative PCR.The experiments include: a)Using different concentrations of oxidized low density lipoprotein(ox-LDL)induce HA-VSMC different times to confirm the optimal conditions for modeling in vitro cell models of AS.b)Testing the inflammatory cytokine release and cell proliferation after different concentration of DES-coated drugs act on AS in vitro cell model.c)Using antibody interference to reduce the expression of inflammatory cytokines and examine the effect of DES-coated drugs on proliferation of AS in vitro cell models to analyzing the mechanism of ISR formation based on SMC.We mainly get the following findings: a)Detecting the contents of total cholesterol and cholesterol ester and the viability of HA-VSMC after induced by different concentration of ox-LDL at different times showed that the rate of cholesterol ester / total cholesterol exceed 50% at 20?g/ml ox-LDL inducing cell at 48 h,and in that time cells are in a more viable proliferative phase.Thus,this condition can be used as the optimal induction time and concentration for establishing AS in vitro cell models.b)DES-coated drugs can trigger an inflammatory response and cause SMC hyperproliferation.By detecting the effect of DES-coated drugs paclitaxel and rapamycin on AS in vitro cell model we found that the expression of proinflammatory cytokines IL-1?,IL-6 and TNF-? were significantly increased(increased with the increasing of drug concentration),and the expression of anti-inflammatory cytokines IL-10,IL-35 and TGF-? decreased significantly(decreased with the increasing of drug concentration).Cell proliferation appeared decreasing and dropped to the lowest point at 1?g/ml of drugs,but still higher than normal SMC.c)By detecting the proliferation of AS in vitro model after interference the expression of inflammatory cytokines we found that IL-6,TNF-?,IL-1?,IL-10 and TGF-? are the directly factors to causing ISR after implantation DES.Paclitaxel caused abnormal proliferation of SMC by increasing the expression of proinflammatory cytokines of IL-6 and TNF-? and decreasing the expression of anti-inflammatory cytokines of IL-10 and TGF-?.Rapamycin made abnormal proliferation of SMC by increasing the levels of proinflammatory cytokines of IL-6 and IL-1? and decreasing the levels of anti-inflammatory cytokines of IL-10 and TGF-?.DES-coated drugs paclitaxel and rapamycin can cause and aggravate the inflammatory response of morbid cells,and thus lead to abnormal proliferation of SMC,suggesting that stent-coated drugs may cause ISR by triggering and aggravating the inflammatory response at the site of stent implantation..This is closely related to the mechanism of ISR,and may indicate the potential mechanism of ISR.The results of this study revealed that early anti-inflammatory treatment is beneficial to the clinical effect and prognosis of DES implantation,and provides a potential ISR therapeutic target,which has important theoretical and practical significance for the prevention and treatment of ISR. |
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