重组白细胞介素13促进成纤维细胞增殖及胶原合成

目的：观察重组白细胞介素13（rIL-13）对3T3细胞的作用，探讨肺纤维化的发生机制。 方法： 3T3细胞分为实验组和对照组，分别加入rIL-13 (80 μg/L)及DMEM培养液, 作用24 h、48 h，利用透射电镜观察成纤维细胞的超微结构，用Hoechst 试剂盒观察细胞DNA形态；用MTT法测细胞增殖率，用Western blotting检测成纤维细胞分泌Ⅰ型胶原以及用放免法检测细胞上清中IL-6、IL-8水平。 结果： 实验组细胞DNA合成增加，细胞核增大，细胞质中可见较多核糖体及线粒体；rIL-13呈剂量依赖方式刺激成纤维细胞增殖，当rIL-13浓度在40-160 μg/L时，细胞增殖率几乎呈直线式增长。对照组及实验组均可检测到Ⅰ型胶原（CoⅠ），对照组分泌胶原的量显著高于对照组（P<0.01）。细胞培养上清中，实验组IL-6、IL-8含量显著高于对照组（P<0.01）。 结论： rIL-13通过促进成纤维细胞增殖及分泌炎性介质和Ⅰ型胶原，可能在肺纤维化的发病机制中发挥关键作用。

Effect of recombinant interleukin-13 on 3T3 fibroblasts in vitro

AIM: To investigate the influence and mechanism of recombinant interleukin-13 (rIL-13) on fibroblasts. METHODS: 3T3 fibroblasts were divided into two groups: the treated group was treated with rIL-13 (80 μg/L, 24 h or 48 h) and the control was without rIL-13 treatment. Transmission electron microscope and Hoechst kit were used to observe morphology of 3T3 fibroblasts in both groups. The activity of proliferation in both groups was investigated and compared by MTT means. Western blot was used to analyze the level of collagen type I induced by rIL-13 in fibroblasts. The levels of IL-6 and IL-8 in the culture supernatants were determined by radioimmunoassay. RESULTS: The more ribosomes and mitochondrions, as well as bigger nuclei were found in the treated group. The production of IL-6 and IL-8, and proliferation ratio of fibroblasts treated with rIL-13 for 24 h or 48 h were increased obviously, compared with the control (P<0.01). The expression of collagen type I protein in treated groups was also significantly higher than that in control (P<0.01). CONCLUSION: rIL-13 upregulates the proliferation of fibroblasts. rIL-13 also has an effect on the production of proinflammatory factors and collagen type I. Taken together, these results suggest that IL-13 may play important roles in the pathogenesis of tissue fibrosis.