Inflammation plays a critical role in the progression of pulmonary fibrosis. Thymosin β4 (Tβ4) has antioxidant, anti-inflammatory, and antifibrotic effects. Although the potent protective role of Tβ4 in bleomycin-induced pulmonary fibrosis has been validated, the underlying mechanism is not clear; moreover, the influence of Tβ4 on lipopolysaccharide (LPS)-induced lung injury/fibrosis has not been reported. Expression of Tβ4 in fibrotic lung tissues was assessed by real-time quantitative reverse-transcription PCR (rt-PCR), immunohistochemistry (IHC), and western blotting. The effects of intraperitoneal adeno-associated virus-Tβ4 (AAV-Tβ4) on LPS-induced lung injury and fibrosis were observed through the evaluation of collagen deposition and α-smooth muscle actin (SMA) expression. In vitro tests with HPAEpiC and HLF-1 cells were performed to confirm the effects of Tβ4. In this study, we evaluated the role of Tβ4 in pulmonary fibrosis and explored the possible underlying mechanisms. Tβ4 was markedly upregulated in human or mouse fibrotic lung tissues. AAV-Tβ4 markedly alleviated LPS-induced oxidative damage, lung injury, inflammation, and fibrosis in mice. Our in vitro experiments also showed that LPS inhibited mitophagy and promoted inflammation via oxidative stress in HPAEpiC, and Tβ4 significantly attenuated LPS-induced mitophagy inhibition, inflammasome activation, and transforming growth factor-β (TGF)-β1-induced epithelial–mesenchymal transition (EMT) in HPAEpiC. Moreover, Tβ4 suppressed the proliferation and attenuated the TGF-β1-induced activation of HLF-1 cells. In conclusion, Tβ4 alleviates LPS-induced lung injury, inflammation, and subsequent fibrosis in mice, suggesting that Tβ4 has a protective role in the pathogenesis of pulmonary fibrosis. Tβ4 is involved in attenuating oxidative injury, promoting mitophagy, and alleviating inflammation and fibrosis. Modulation of Tβ4 might be a novel strategy for treating pulmonary fibrosis.

炎症在肺纤维化的进展中起关键作用。胸腺素 β4 (Tβ4) 具有抗氧化、抗炎和抗纤维化作用。尽管 Tβ4 在博来霉素诱导的肺纤维化中的有效保护作用已得到验证，但其潜在机制尚不清楚。此外，尚未报道 Tβ4 对脂多糖 (LPS) 诱导的肺损伤/纤维化的影响。通过实时定量逆转录 PCR (rt-PCR)、免疫组织化学 (IHC) 和蛋白质印迹评估 Tβ4 在纤维化肺组织中的表达。通过评估胶原沉积和α-平滑肌肌动蛋白（SMA）的表达，观察腹腔内腺相关病毒-Tβ4（AAV-Tβ4）对LPS诱导的肺损伤和纤维化的影响。用 HPAEpiC 和 HLF-1 细胞进行体外试验以确认 Tβ4 的作用。在本研究中，我们评估了 Tβ4 在肺纤维化中的作用，并探讨了可能的潜在机制。Tβ4 在人或小鼠纤维化肺组织中显着上调。AAV-Tβ4 显着减轻 LPS 诱导的小鼠氧化损伤、肺损伤、炎症和纤维化。我们的体外实验还表明，LPS 通过 HPAEpiC 中的氧化应激抑制线粒体自噬并促进炎症，而 Tβ4 显着减弱了 LPS 诱导的线粒体自噬抑制、炎症小体激活和转化生长因子-β (TGF)-β1 诱导的上皮-间质转化。 EMT）在 HPAEpiC 中。此外，Tβ4 抑制增殖并减弱 TGF-β1 诱导的 HLF-1 细胞活化。总之，Tβ4 减轻 LPS 诱导的肺损伤，炎症和随后的小鼠纤维化，表明 Tβ4 在肺纤维化的发病机制中具有保护作用。Tβ4 参与减轻氧化损伤、促进线粒体自噬以及减轻炎症和纤维化。调节 Tβ4 可能是治疗肺纤维化的新策略。