Effects of recombinant retroviral vector mediated human insulin like growth factor-1 gene transfection on skeletal muscle growth in rat / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>This study transferred a recombinant gene encoding human insulin like growth factor-1 (hIGF-1) into modified primary skeletal myoblasts with a retroviral vector (pLgXSN) and determined whether the hIGF-1 promoted growth of skeletal muscle in rat.</p><p><b>METHODS</b>hIGF-1cDNA was amplified in vitro from normal human liver cells by using RT-PCR and cloned into plasmid vector pLgXSN. The recombinant vector pLghIGF-1SN and control vector pLgGFPSN were transfected into packaging cell PT67 and G418 was used to select positive colony. Myoblasts were infected with a high titre viral supernatant and transduction efficiency was evaluated as GFP expression. The expression of hIGF-1 mRNA in myoblasts was investigated by immunocytochemistry and RT-PCR. MTT assays detected the growth of myoblasts in vitro. Myoblasts transduced with pLghIGF-1SN were injected into hind limb muscles of 10 - 12 week male SD rats. Formed tissues were harvested 4 weeks later. Myocyte diameter, mean weight of hind limb and body were measured to evaluate the skeletal muscle growth.</p><p><b>RESULTS</b>Recombinant retroviral plasmid vector pLghIGF-1SN was constructed successfully. The titre of the packaged recombinant retrovirus was 1 x 10(6) cfu/ml. The transfection rate of PT67 cells reached 100% after G418 screening. hIGF-1 expression was positive in myoblast-IGF-1. The proliferation rate of myoblast-IGF-1 in vitro was higher than GFP-myoblast or myoblast (P < 0.05). The mean weights of hind limb and body of rats injected myoblast-IGF-1 were higher than those of the rats injected with myoblast-GFP or myoblast (P < 0.05). Myocyte diameter had a significant increase in IGF-1 group compared to GFP group and myoblast group (P < 0.05).</p><p><b>CONCLUSIONS</b>The transfection of the human IGF-1 gene mediated by a retroviral vector can promote the growth of skeletal muscle in rats. Genetically modified primary skeletal myoblasts provide a possibly effective approach to treat some skeletal muscle diseases.</p>

Effect of tumor necrosis factor-it on the expression of ATP binding cassette transporter A1 in THP-1 macrophage foam ceils / 中华老年医学杂志

Objective To investigate the influence of tumor necrosis factor-?(TNF-?) on ATP binding cassette transporter A1(ABCA1)in THP-1 macrophage foam cells, and the intervention effect of nuclear factor-?B(NF-?B) inhibitor TPCK on the TNF-?, so as to determine the role of TNF-?/ NF-?B in cellular cholesterol efflux. Methods Foam cells were transformed from THP1 cells. The correlation of cellular cholesterol efflux from foam cells with different concentrations and time stimulated by TNF-? were estimated. Subsequently foam cells were treated with TNF-? at satulated concentration(10.0 ng/ml ), TPCK(10?mol/L),or TPCK(10?mol/L) pretreated for 60 min before TNF-? stimulation. ABCA1 gene expression was analyzed by RT-PCR. ABCA1 protein level was detected by Western blot. Results TNF-? decreased cellular cholesterol efflux of foam cells in concentration-and time-dependent manner. 10 ng/ml of TNF-? down-regulated the levels of both ABCA1 mRNA and protein expressions in time-dependent manner. TPCK was observed to efficiently block the suppressive effect of TNF-? on ABCA1. Conclusions TNF-? decreases cellular cholesterol efflux mainly through the down-regulation of ABCA1. TPCK, an inhibitor of NF-?B activation, is observed to partly block the suppressive effect of TNF-? on ABCA1, suggesting a mechanism involving NF-?B signal transduction. TNF-?/NF-?B might play a critical role in the progression of atherosclerosis by decreasing cellular cholesterol efflux from foam cells.