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目的观察硫化氢(H2S)对博莱霉素所致大鼠肺纤维化的影响,并探讨其是否通过转化生长因子-β1(TGF-β1)/Smad信号通路发挥作用。方法 SD大鼠50只随机分为正常对照组、假手术组、模型组、硫氢化钠(Na HS)组和地塞米松组,每组10只,假手术组大鼠以生理盐水气管内注入,而后3组大鼠以博莱霉素A5气管内注入制备肺纤维化模型。自第2天起,Na HS组、地塞米松组大鼠分别以Na HS、地塞米松腹腔注射,其余3组腹腔注射等量生理盐水。全部大鼠第28天处死,留取肺组织,行HE和Masson染色,通过试剂盒测定肺组织羟脯氨酸(HYP)含量,采用实时荧光定量PCR和Western blot分别检测肺组织中TGF-β1、Smad2、Smad3、Smad7、α平滑肌肌动蛋白(α-SMA)、Ⅰ型胶原(ColⅠ)、Ⅲ型胶原(ColⅢ)m RNA和蛋白表达。结果与模型组比较,Na HS组和地塞米松组肺泡炎症与肺纤维化程度明显减轻(P<0.01)。与正常对照组或假手术组比较,模型组肺组织HYP含量以及TGF-β1、Smad 2、Smad 3、α-SMA、ColⅠ、ColⅢm RNA和蛋白表达水平升高,但Smad 7 m RNA和蛋白表达水平降低,差异均有统计学意义(P<0.01)。通过Na HS或地塞米松处理后,肺组织HYP含量以及TGF-β1、Smad 2、Smad 3、α-SMA、ColⅠ、ColⅢm RNA和蛋白表达水平减少,而Smad 7 m RNA和蛋白表达水平增加,与模型组比较,差异均有统计学意义(P<0.01)。然而,Na HS组与地塞米松组以及假手术组与正常对照组上述指标相比无显著性差异(P>0.05)。结论 H2S可能通过抑制TGF-β1/Smad信号转导通路下调α-SMA表达,从而减少ColⅠ、ColⅢ合成发挥抗大鼠肺纤维化作用。
Objective To observe the effect of hydrogen sulfide (H2S) on bleomycin-induced pulmonary fibrosis in rats and explore whether TGF-β1 / TGF-β1 / Smad signaling pathways play a role. Methods Fifty SD rats were randomly divided into normal control group, sham operation group, model group, sodium hydrosulfide (Na HS) group and dexamethasone group, with 10 rats in each group. Rats in sham operation group were injected with saline , And then three groups of rats with bleomycin A5 intratracheal injection of pulmonary fibrosis model. From the second day onward, rats in Na HS group and dexamethasone group were injected intraperitoneally with Na HS and dexamethasone, and the other three groups were injected with the same amount of normal saline. All the rats were killed on the 28th day, and the lung tissues were collected for HE staining and Masson staining. Hydroxyproline (HYP) content in the lung tissue was determined by kit. The expression of TGF-β1 in lung tissue was detected by real-time fluorescence quantitative PCR and Western blot , Smad2, Smad3, Smad7, α-SMA, ColⅠ, Col Ⅲ mRNA and protein expression were detected. Results Compared with model group, the degree of alveolar inflammation and pulmonary fibrosis in NaHS group and dexamethasone group were significantly reduced (P <0.01). Compared with normal control group or sham operation group, the level of HYP and the mRNA and protein expression of TGF-β1, Smad 2, Smad 3, α-SMA, ColⅠ, Col Ⅲ increased in model group Level decreased, the difference was statistically significant (P <0.01). After treatment with Na HS or dexamethasone, the levels of HYP and the expression of mRNA and protein of TGF-β1, Smad 2, Smad 3, α-SMA, ColⅠ and Col Ⅲ decreased, while the levels of Smad 7 mRNA and protein increased, Compared with the model group, the differences were statistically significant (P <0.01). However, there was no significant difference between the Na HS group and the dexamethasone group and between the sham operation group and the normal control group (P> 0.05). Conclusion H2S may down-regulate the expression of α-SMA by inhibiting the TGF-β1 / Smad signaling pathway, thereby reducing the ColⅠ and Col Ⅲ synthesis to exert anti-pulmonary fibrosis in rats.