title: Change of p16(INK4a) and PCNA protein expression in myocardium after injection of hIGF-1 gene modified skeletal myoblasts into post-infarction rats.
abstract: This study examined the change of p16(INK4a) and PCNA protein expression in myocardium after injection of hIGF-1 gene modified skeletal myoblasts into post-infarction rats. HIGF-1 gene modified skeletal myoblasts (hIGF-1-myoblasts) were injected into hind limb muscles of 18 post-infraction rats (experimental group). Primary-myoblasts were injected into 18 post-infraction rats (control group) and 12 non-infarction rats (sham group). Expression of p16(INK4a) and PCNA protein in myocardiums were separately detected immunocytochemically 1, 2 and 4 weeks after the injection. The level of hIGF-1 and rIGF-1 protein in serum and myocardium were detected by enzyme-linked immunosorbent assay (ELISA). Compared with the sham group, the percentage of p16(INK4a) and PCNA positive cells reached a peak after 1 week in the control group and the experimental group (P<0.01). Moreover, the percentage of p16(INK4a)-positive cells in the experimental group was lower than in control group whereas the percentage of PCNA-positive cells was lower in the control group than in the experimental group (P<0.01). The percentage of p16(INK4a)-positive cells in the experimental group and the percentage of PCNA-positive cells in the control group were close to that in the sham group from the 2nd week (P>0.05). ELISA analysis disclosed that the myocardium level of rIGF-1 protein increased gradually in the controls and especially in the experimental group (P<0.01). The serum level of rIGF-1 decreased significantly in post-infraction rats, but these conditions were improved in the experimental group (P<0.01). The hIGF-1 protein in serum and myocardium were detected from the 1st week to the 4th week in the experimental group. Statistical analysis revealed significant associations of myocardium level of hIGF-1 protein with expression of p16(INK4a) and PCNA protein (r=-0.323, P<0.05; r=0.647, P<0.01). It is concluded that genetically hIGF-1-myoblast provides a means for constant synthesis and release of hIGF-1. It could not only improve the expression of rIGF-1 and PCNA protein in myocardium, but also suppress the expression of p16(INK4a) protein for 30 days in post-infraction rats. Myoblasts-mediated IGF-1 gene therapy may provide a new alternative for the clinical treatment of heart failure.
authors.affiliation: The Institute of Cardiovascular Disease, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, the Laboratory of Target Biology Therapy in Hubei Province, Wuhan 430022, China. gaoyz606@sina.com
authors.forename: Yanzhang
authors.initials: Y
authors.lastname: Gao
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Lu
authors.forename: Shaohua
authors.initials: S
authors.lastname: Mi
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Liu
authors.forename: Guanhua
authors.initials: G
authors.lastname: Su
authors.forename: Shuling
authors.initials: S
authors.lastname: Rong
mesh_terms: D000818:Animals; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism*; D015316:Genetic Therapy; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008297:Male; D032448:Myoblasts, Skeletal / Q000378:metabolism*; D009203:Myocardial Infarction / Q000378:metabolism / Q000628:therapy; D009206:Myocardium / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D018809:Proliferating Cell Nuclear Antigen; D007334:Insulin-Like Growth Factor I