TP 40对血管平滑肌细胞增殖的抑制作用

Inhibitory effect of TP40 on vascular smooth muscle cell proliferation

目的：探讨转化生长因子α（ Ｔ Ｇ Ｆα）绿脓杆菌外毒素（ Ｐ Ｅ４０）融合蛋白（ Ｔ Ｐ４０）对血管平滑肌细胞（ Ｓ Ｍ Ｃ）增殖的抑制作用。方法：用免疫组化 Ａ Ｂ Ｃ 法检测原代培养增殖期及静止期 Ｓ Ｍ Ｃ表皮生长因子受体（ Ｅ Ｇ Ｆ Ｒ）的表达，用结晶紫染色法和３ Ｈ亮氨酸掺入法检测 Ｔ Ｐ４０ 对增殖期和静止期 Ｓ Ｍ Ｃ增殖及蛋白质合成的抑制，用过量 Ｅ Ｇ Ｆ竞争抑制 Ｔ Ｐ４０ 的细胞毒作用。结果：增殖期 Ｓ Ｍ Ｃ能高水平表达 Ｅ Ｇ Ｆ Ｒ，静止期 Ｓ Ｍ Ｃ表达水平较低。 Ｔ Ｐ４０ 浓度为０．１ 和１０ ｎｇ／ｍ ｌ时，对增殖期 Ｓ Ｍ Ｃ增殖及蛋白质合成的抑制作用与静止期 Ｓ Ｍ Ｃ无差异（ Ｐ＞ ０．０５）；１０ 及１００ ｎｇ／ｍ ｌ时，对增殖期 Ｓ Ｍ Ｃ增殖及蛋白质合成的抑制作用较静止期 Ｓ Ｍ Ｃ强（ Ｐ＜ ０．０１）；过量 Ｅ Ｇ Ｆ能完全抑制 Ｔ Ｐ４０ 的细胞毒作用。结论： Ｔ Ｐ４０ 对增殖期 Ｓ Ｍ Ｃ的增殖具有较强的抑制作用，对静止期 Ｓ Ｍ Ｃ则影响较小，作用部位为细胞的 Ｅ Ｇ Ｆ Ｒ。

Objective: To investigate inhibitory effect of recombinant TGFα PE40 (TP40) on cultured vascular smooth muscle cells (SMC). Methods: Expression of epidermal growth factor receptor (EGFR) in SMC was analysed with immunohistochemistry. Inhibitory effects of TP40 on SMC proliferation and protein synthesis were analysed by crystal violet staining and 3H leucine incorporation. Competition assays were performed by the addition of excess of EGF. Results: Expression of EGFR was found in rapidly proliferating SMC, not found in quiescent SMC. Inhibitory effects of TP40 on rapidly proliferating SMC proliferation and protein synthsis was much higher than on quiescent SMC. Excess EGF can completely block inhibitory effects of TP40. Conclusion: It indicates that TP40 can significantly inhibit the proliferation of rapidly proliferating SMC, but less confluence quiescent SMC. The cytotoxic effects of TP40 are specifically mediaed by EGFR.