5-羟色胺在胆管上皮细胞与门管成纤维细胞自分泌／旁分泌中的作用

目的探讨5-羟色胺（5_hydmxytryptamine，5-HT）在胆管上皮细胞（biliary epithelia cells，BECs）与门管区成纤维细胞（portal fibroblasts，PFs）之间自分泌／旁分泌效应中的意义，阐述两种细胞之间的相互作用。方法体外细胞培养分为6组：1）BECs组单独培养；2）BECs＋TGF—β1组，BECs单独培养，用2ng／ml重组TGF—β1干预24h后更换培养液；3）BECs＋5-HT组，BECs单独培养，以60ng／ml的5-HT干预48h后更换培养液；4）PFs组单独培养；5）PFs＋5-HT组，PFs单独培养，以60ng／ml的5-HT干预48h后更换培养液；6）BECs＋PFs，共同培养。各组均在培养72h后，以酶联免疫吸附分析法（ELISA）检测培养介质内5-HT、TGF—β1含量；实时荧光定量多聚酶链反应（QRT—PCR）检测BECs内色氨酸羟化酶（TPHl、TPH2）和5-HT受体1A、1B表达；以BrdU、α—SMA分别作为BECs增殖及PFs转化为肌纤维母细胞（myofibroblasts，MFs）的标志，免疫细胞化学检测。结果单独培养的BECs表达5-HT合成限速酶TPH1、TPH2及5-HTRIA、5-HTR1B，5-HT分泌较高而BECs增殖不明显；经TGF—β1处理或与PFs共培养后，TPH1、TPH2表达各减少80％和87％，5-HTR1A、5-HTR1B表达分别减少75％和85％，BECs增殖明显。单独培养的PFs分泌TGF—β1，部分呈α—SMA阳性的MFs；经5-HT处理或与BECs共培养后，TGF—β1表达及MFs显著增加。结论BECs来源的5-HT以及PFs来源的TGF—β1介导BECs与PFs之间的自分泌与旁分泌效应，维持BECs增殖和PFs向MFs的转化，在胆管病发病机制中可能具有重要意义。

Role of serotonin in the autocrine / paracrine between cholangiocytes and portal fibroblasts

Objective To evaluate the role of serotonin （5-HT） in the crosstalk between cholangiocytes （biliary epithelia cells, BECs） and portal fibroblasts （PFs）. Methods Cells were cultured and divided into 6 groups. 1） BECs were cultured alone; 2） BECs ＋ TGF- β1： BECs were cultured alone and then were treated with 2 ng/ml of recombinant transforming growth factor β1 （TGF- β1） for 24 h; 3） BECs ＋ 5-HT： BECs were cultured alone and then were treated with 60 ng/ml of 5-HT for 48 h; 4） PFs were cultured alone; 5） PFs ＋ 5-HT： PFs were cultured alone and then were treated with 60 ng/ml of 5-HT for 48 h; 6） BECs ＋ PFs： BECs and PFs were co-cultured. After culturing for 72 h, the concentration of 5-HT or TGF- β1 in culture medium was detected by ELISA. Expressions of TPH1, TPH2, 5-HTR1A, 5-HTR1B mRNA in BECs were detected by real-time QRT-PCR. BrdU and α -SMA as the marker of BECs proliferation and myofibroblastic transdifferentiation of PFs were evaluated by immunocytochemistry. Results Mono-cultured BECs expressed TPH1, TPH2, 5-HTR1A, 5-HTR1B mRNA with hypersecretion of 5-HT and slight proliferation of BECs. After being treated by TGF- β1 or co-cultured with PFs, BECs reduced the expression of TPH1 by 80% and TPH2 by 87%. Moreover, 5-HTR1A and HTR1B mRNA expression in BECs also dropped by 75% and 85% respectively, companied by the increasment of BECs proliferation. Mono-cultured PFs produced TGF- β1 with some MFs showing positive staining. However, after being treated by 5-HT or co-cultured with BECs, TGF- β1 secretion and et -SMA-positive cells were significantly increased. Conclusion 5-HT derived from BECs and TGF- β1 produced by PFs can mediate the autocrine and paracrine effects between BECs and PFs, and maintain the proliferation of BECs and the conversion of PFs to MFs, which may be meaningful to the pathogenesis of cholangiopathies.