血管紧张素Ⅱ诱导大鼠胰星状细胞增殖和胶原合成

Ang Ⅱ induces proliferation and collagen synthesis in rat pancreatic stellate cells

目的：研究血管紧张素Ⅱ（angiotensinⅡ，AngⅡ）对大鼠胰星状细胞（pancreatic stellate cells，PSCs）增殖和活化的影响。方法：取第4～7代培养的大鼠PSCs，采用无血清DMEM培养液培养48h使细胞同步静止化后，换含1、10和100nmol／LAngⅡ的无血清培养液继续培养24h或48h；另外，在加入100nmol／LAngII无血清培养液前加入100nmol／LAT1受体拮抗剂ZD7155或AT2受体拮抗剂PD123319。分别采用[^3H]-胸嘧啶核苷掺入、[^3H]-脯氨酸掺入、Western印迹和Northern印迹法动态检测细胞DNA合成速率、胶原合成速率、α-平滑肌动蛋白和Ⅰ型前胶原mRNA表达。结杲：与正常对照组比较，1nmol／LAngⅡ刺激24h后细胞DNA合成率无显著增加（P〉0．05），而10和100nmol／L处理组细胞DNA合成率显著增加（P值均〈0．05）；刺激48h后，1、10和100nmol／LAngⅡ处理组细胞胶原合成率和Ⅰ型前胶原mRNA表达水平均明显增加（P值均〈0．05），但α-平滑肌动蛋白表达无明显变化（P值均〉0．05）。与AngⅡ（100nmol／L）处理组比较，AngⅡ（100nmol／L）＋ZD7155（100nmol／L）处理组细胞DNA合成率、胶原合成率和Ⅰ型前胶原mRNA表达水平均显著下降（P值均〈0．01），而AngⅡ（100nmol／L）＋PD123319（100nmol／L）处理组均无明显变化（P值均〉0．05）。结论：AngⅡ通过AT1受体介导，可剂量依赖性诱导大鼠PSCs增殖和胶原合成，从而参与胰腺纤维化的发生。

Objective：To investigate the effects of Ang Ⅱ on cellular proliferation and activation of cultured rat pancreatic stellate cells （PSCs）. Methods.. Growth arrest was induced in the 4^th-7^sh passage rat PSCs by culturing with serum-free DMEM for 48 h, then the PSCs were incubated for 24 h or 48 h with serum-free culture medium containing different concentrations of Ang Ⅱ （0, 1, 10, and 100 nmol/L） in the presence or absence of ZD7155 and PD123319, the specific antagonists of Ang Ⅱtype 1 and 2 receptors （AT1 and AT2）. The DNA synthesis rate was investigated by using [^3 H]thymidine incorporation, collagen synthesis rate by [^3 H]proline incorporation, α-smooth muscle actin （α-SMA） expression by Western blot analysis, and procollagen α1（Ⅰ） mRNA expression by Northern blot analysis. Results： Treatment of cells with Ang Ⅱ for 24 h resulted in a dose-dependent increase in DNA synthesis, with statistically significant increase at 10 and 100 nmol/L （both P〈0.05 vs normal control）. Treatment for 48 h with Ang Ⅱ at concentrations of 1, 10, and 100 nmol/L dose-dependently induced collagen synthesis and procollagen α1（ Ⅰ ） mRNA expression （both P〈0.05 vs normal control）. The above effects of Ang Ⅱ （100 nmol/L） were inhibited by ZD7155 （P〈0.01 vs Ang Ⅱ alone） but not by PD123319 （P〉0.05 vs Ang Ⅱ alone）. No significant increase in the expression of α-SMA protein was observed in response to stimulation with increasing concentrations of Ang Ⅱ . Conclusion.. The present study indicates that Ang Ⅱ , mediated by AT1 receptor, can dose-dependently induce the proliferation and collagen production in rat PSCs, thus participating in the pancreatic fibrogenesis.