胰岛素对高血压大鼠血管平滑肌细胞血小板源生长因子A链和转化生长因子β1表达的影响

探讨胰岛素对体外培养的血管平滑肌细胞（VSMC）增生及其长型血小板源生长因子A（PDGF－A）链和转化生长因子β1（TGFβ1）mRNA表达的影响。结果发现：（1）胰岛素促进自发型高血压大鼠的血管平滑肌细胞（SHR－VSMC）增生，且呈浓度依赖性；而对正常血压的Wistar-kyota大鼠的血管平滑肌细胞（WKY－VSMC）增生无影响。（2）定量RT－PCR分析显示，胰岛素加强WKY－VSMC的TGFβ1mRNA的表达（P＜0．01）。但是减少SHR－VSMC的TGFβ1mRNA的表达（P＜0．001）。（3）胰岛素对二株系VSMC的长型PDGF－A上对表达水平无影响。结果表明，胰岛素选择性地加强SHR－VSMC的增殖，而对WKY－VSMC的增殖无影响。这可能和胰岛素能上调WKY－VSMC自分泌TGFβ1有关；而在SHR－VSMC，此反馈抑制失常，结果SHR－VSMC加速生长。

Effects of Insulin on PDGF-A chain and TGF

In this study we examined the effect of insulin on cell proliferation and the expression of long-form platelet derived growth factor A-chain (PDGF-A) and transforming growth factor β1 (TGFβ1) in cultured vascular smooth muscle cells (VSMC) . It was found: (1) Insulin enhanced the hyperproliferation of VSMC from spontaneously hypertentive rats (SHR) in dose-dependent way, with no effect on VSMC from Wistar-Kyoto rats (WKY); (2) The level of TGF β1 mRNA, when evaluated by quantitative RT-PCR analysis, was enhanced by insulin in VSMC from WKY rats, but decreased in VSMC from SHR. (3) Expression of the long-form of PDGF-A chain mRNA was not affected by insulin in both strains VSMC. It suggests that the increase in the expression of the TGF β1 by insulin may facilitate the ability of endogenous TGF β1 to counteract the stimulatory effect of insulin on growth in VSMC from WKY rats, whereas the defective regulation of TGF β1 by insulin may contribute to the exaggerated growth in VSMC from SHR.