title: [Effects of Rapamycin and Rapamycin-loaded Poly(lactic-co-glycolic)Acid Nanoparticles on Apoptosis and Expression of bcl-2 and p27(kip1) Proteins of Human Umbilical Arterial Vascular Smooth Muscle Cell].
abstract: OBJECTIVE
  To investgate the effects of rapamycin(RPM)and RPM-loaded poly(lactic-co-glycolic)acid(PLGA)nanoparticles(NPs)on the apoptosis of human umbilical arterial vascular smooth muscle cells(HUASMCs)in vitro and expression of bcl-2 and p27(kip1) protein.
  
  
  METHODS
  HUASMCs were cultured in vitro and divided to RPM and RPM-PLGA-NPs groups treated at 3 different concentration by 12 and 24 hours,with M231-smooth muscle growth supplements medium and null-PLGA-NPs treated groups as controlled. The apoptosis of HUASMCs was determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining and flow cytometry. The expressions of bcl-2 and p27(kip1) were detected by streptacidin/peroxidase immunohistochemical method. The effect on cellular proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidecolorimetry.
  
  
  RESULTS
  The proliferation of HUASMCs was inhibited by RPM and RPM-PLGA-NPs in a dose-dependent manner. DNA electrophoresis showed DNA ladder in RPM and RPM-PLGA-NPs groups and classical scalar strips in control groups. The apoptotic indexes of RPM 100 ng/ml group and RPM-PLGA-NPs 500 ng/ml group detected by flow cytometry were(45.45<2.36)% and(35.04<5.64)%,respectively,which were significantly higher than that of M231-smooth muscle growth supplements control group [(2.60<0.95)%,all P<0.01]. The apoptotic indexes of groups incubated with RPM and RPM-PLGA-NPs for 24 hours were significantly higher than those of groups which incubated for 12 hours(P<0.05,P<0.01). The positive expression indexes(PEI)of p27(kip1) and bcl-2 protein were higher in RPM and RPM-PLGA-NPs groups than that of control groups. The Spearman's rank correlation coefficient test showed that there was no significant correlation between the PEI of p27(kip1) and the apoptotic indexes in the RPM group and RPM-PLGA-NPs group(P>0.05).
  
  
  CONCLUSIONS
  Rapamycin-loaded PLGA nanoparticles and rapamycin have similar effects in inhibiting proliferation and inducing apoptosis;meanwhile,they upregulate the expression of p27(kip1) protein without downregulating the expression of bcl-2 protein in HUASMCs in vitro. RPM-PLGA-NPs has more potent pro-apoptotic effect than equivalent dose of RPM but is not linearly correlated with the p27(kip1) expression level.
authors.affiliation: Heart Center,the First Hospital of Tsinghua University,Beijing 100016,China.
authors.forename: Li-fu
authors.initials: LF
authors.lastname: Miao
authors.affiliation: Heart Center,the First Hospital of Tsinghua University,Beijing 100016,China.
authors.forename: Yong-liang
authors.initials: YL
authors.lastname: Cui
authors.affiliation: Heart Center,the First Hospital of Tsinghua University,Beijing 100016,China.
authors.forename: Yan-ping
authors.initials: YP
authors.lastname: Yin
authors.affiliation: Heart Center,the First Hospital of Tsinghua University,Beijing 100016,China.
authors.forename: Lian-feng
authors.initials: LF
authors.lastname: Chen
authors.affiliation: Department of Pathology,Institute of Basic Medical Sciences,CAMS and PUMC,Beijing 100730,China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Pathology,Institute of Basic Medical Sciences,CAMS and PUMC,Beijing 100730,China.
authors.forename: Pei-mao
authors.initials: PM
authors.lastname: Liu
authors.affiliation: Department of Cardiology,PUMC Hospital,CAMS and PUMC,Beijing 100730,China.
authors.forename: Wen-ling
authors.initials: WL
authors.lastname: Zhu
authors.affiliation: Tianjin Biomedical Materials Key Laboratory,Institute of Biomedical Engineering,CAMS and PUMC,Tianjin 300192,China.
authors.forename: Cun-Xian
authors.initials: CX
authors.lastname: Song
authors.affiliation: Tianjin Biomedical Materials Key Laboratory,Institute of Biomedical Engineering,CAMS and PUMC,Tianjin 300192,China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
mesh_terms: D017209:Apoptosis; D049109:Cell Proliferation; D002478:Cells, Cultured; D050760:Cyclin-Dependent Kinase Inhibitor p27; D006801:Humans; D020287:In Situ Nick-End Labeling; D019344:Lactic Acid; D009131:Muscle, Smooth, Vascular; D032389:Myocytes, Smooth Muscle; D053758:Nanoparticles; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D020123:Sirolimus; D014469:Umbilical Arteries
chemical_list: C436291:CDKN1B protein, human; D050760:Cyclin-Dependent Kinase Inhibitor p27; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D020123:Sirolimus