Airway fibrosis is among the pathological manifestations of benign central airway obstruction noted in the absence of effective treatments and requires new drug targets to be developed. Slit guidance ligand 2–roundabout guidance receptor 1 (Slit2–Robo1) is involved in fibrosis and organ development. However, its significance in airway fibrosis has not yet been reported. The study explored how the recombinant protein Slit2 functions in transforming growth factor-β1 (TGF-β1)-mediated airway fibrosis in vivo and in vitro. In this study, Slit2 expression initially increased in the tracheal granulation tissues of patients with tracheobronchial stenosis but decreased in the fibrotic tissue. In primary rat tracheal fibroblasts (RTFs), recombinant Slit2 inhibited the expression of extracellular matrices such as Timp1, α-SMA, and COL1A2, whereas recombinant TGF-β1 promoted the expression of Robo1, α-SMA, and COL1A2. Slit2 and TGF-β1 played a mutual inhibitory role in RTFs. Slit2 supplementation and Robo1 downregulation inhibited excessive extracellular matrix (ECM) deposition induced by TGF-β1 in RTFs via the TGF-β1/Smad3 pathway. Ultimately, exogenous Slit2 and Robo1 knockdown-mediated attenuation of airway fibrosis were validated in a trauma-induced rat airway obstruction model. These findings demonstrate that recombinant Slit2 alleviated pathologic tracheobronchial healing by attenuating excessive ECM deposition. Slit2–Robo1 is an attractive target for further exploring the mechanisms and treatment of benign central airway obstruction.

气道纤维化是良性中央气道阻塞的病理表现之一，缺乏有效的治疗方法，需要开发新的药物靶点。狭缝引导配体 2–环形引导受体 1 (Slit2–Robo1) 参与纤维化和器官发育。然而，其在气道纤维化中的重要性尚未被报道。该研究探讨了重组蛋白Slit2在体内和体外如何在转化生长因子-β1（TGF-β1）介导的气道纤维化中发挥作用。本研究中,Slit2表达最初在气管支气管狭窄患者的气管肉芽组织中表达升高,但在纤维化组织中表达降低。在原代大鼠气管成纤维细胞（RTF）中，重组 Slit2 抑制细胞外基质（如 Timp1、α-SMA 和 COL1A2）的表达，而重组 TGF-β1 则促进 Robo1、α-SMA 和 COL1A2 的表达。Slit2和TGF-β1在RTFs中发挥相互抑制作用。补充 Slit2 和 Robo1 下调可通过 TGF-β1/Smad3 途径抑制 RTF 中 TGF-β1 诱导的过度细胞外基质 (ECM) 沉积。最终，外源性 Slit2 和 Robo1 敲低介导的气道纤维化减弱作用在创伤诱导的大鼠气道阻塞模型中得到了验证。这些发现表明，重组 Slit2 通过减少过度的 ECM 沉积来减轻病理性气管支气管愈合。Slit2–Robo1 是进一步探索良性中央气道阻塞的机制和治疗的一个有吸引力的靶点。