内皮抑素通过Notch1/血小板源生长因子信号通路对小鼠肺纤维化的抑制作用

目的研究内皮抑素通过Notch1/血小板源生长因子（Notch1/PDGF）信号通路对小鼠肺纤维化的抑制作用。 方法将30只小鼠分为对照组、模型组和内皮抑素组，每组各10只。模型组和内皮抑素组小鼠给予气管内注射博莱霉素（5 mg/kg）以建立肺纤维化模型，对照组小鼠仅注射等量等渗NaCl溶液；内皮抑素组小鼠每天腹腔注射内皮抑素（2.3 mg/kg），对照组和模型组小鼠每天腹腔注射等量等渗NaCl溶液，所有小鼠均持续注射21 d。21 d后处死所有小鼠，取左肺组织行病理学染色；取右肺组织，应用Western-blotting法检测Collagen I，Notch1/PDGF信号通路相关蛋白转化生长因子β1（TGF-β1）、Hes1、Hey1、PDGF-B、PDGF受体β（PDGFR-β）及周细胞相关蛋白Desmin、神经元-胶质细胞抗原2（NG2）及α-平滑肌肌动蛋白（α-SMA）的表达水平。 结果光镜下，可见对照组小鼠肺泡结构完整，未见异常胶原蛋白；模型组小鼠肺泡结构被破坏，有大量胶原蛋白沉积；内皮抑素组小鼠可见肺组织结构相对完整，而胶原蛋白明显减少。3组小鼠间Collagen I、TGF-β1、Hes1、Hey1、PDGF-B、PDGFR-β、Desmin、NG2及α-SMA蛋白表达水平的比较，差异均有统计学意义（F = 12.068、30.603、29.757、35.451、16.059、16.420、24.512、19.084、28.102，P均<0.001）。进一步两两比较发现，内皮抑素组小鼠的Collagen I、TGF-β1、Hes1、Hey1、PDGF-B、PDGFR-β及α-SMA蛋白表达水平均显著低于模型组小鼠，Desmin及NG2蛋白表达水平均显著高于模型组小鼠（P均<0.05）；而内皮抑素组与对照组小鼠间Collagen I、TGF-β1、Hes1、Hey1、PDGF-B、PDGFR-β、Desmin、NG2及α-SMA蛋白表达水平的比较，差异均无统计学意义（P均>0.05）。 结论内皮抑素可通过Notch1/PDGF信号通路抑制周细胞向肌成纤维细胞转化，从而影响小鼠肺纤维化。

Inhibitory effect of endostatin on pulmonary fibrosis in mice through Notch1/platelet-derived growth factor signaling pathway

ObjectiveTo investigate the inhibitory effect of endostatin on pulmonary fibrosis in mice via the Notch1/platelet-derived growth factor (PDGF) signaling pathway. MethodsA total of 30 mice were randomly divided into a control group, a model group and an endostatin group, with 10 mice in each group. Mice in the model and endostatin groups were given bleomycin (5 mg/kg) by intratracheal injection to establish a model of pulmonary fibrosis, and mice in the control group were injected with equal volume of isotonic NaCl solution. Then, mice in the endostatin group were given endostatin (2.3 mg/kg) daily, and mice in the control and model groups were injected with equal volume of isotonic NaCl solution, all by intraperitoneal injection for 21 days; afterwards, all mice were sacrificed. The left lung tissue was taken for pathological staining, and the right lung tissue was used to detect expression levels of Collagen I, Notch1/PDGF signaling pathway-related proteins transforming growth factor-beta 1 (TGF-β1), Hes1, Hey1, PDGF-B, PDGF receptor-beta (PDGFR-β)], and pericyte proteins Desmin, neuron-glial antigen 2 (NG2), alpha-smooth muscle actin (α-SMA)] by Western-blotting. ResultsUnder light microscope, the alveolar structure was intact and no abnormal collagen was found in the control group; the alveolar structure was destroyed and massive collagen was deposited in the model group; the alveolar structure was relatively intact and collagen significantly reduced in the endostatin group. The expression levels of Collagen I, TGF-β1, Hes1, Hey1, PDGF-B, PDGFR-β, Desmin, NG2 and α-SMA were significantly different among three groups (F = 12.068, 30.603, 29.757, 35.451, 16.059, 16.420, 24.512, 19.084, 28.102; all P < 0.001). Meanwhile, compared with the model group, the expression levels of Collagen I, TGF-β1, Hes1, Hey1, PDGF-B, PDGFR-β and α-SMA were much lower and the expression levels of Desmin and NG2 were much higher in the endostatin group (all P < 0.05). However, the expression levels of Collagen I, TGF-β1, Hes1, Hey1, PDGF-B, PDGFR-β, Desmin, NG2 and α-SMA showed no significant differences between the endostatin group and control group (all P>0.05). ConclusionEndostatin inhibits the transformation of pericytes into myofibroblasts by the Notch1/PDGF signaling pathway, and thereby restrains pulmonary fibrosis in mice.