Objective:This study aims to explore the effects of paclitaxel on the differentiation of human lung fibroblasts(HLFs) into myofibroblasts induced by recombinant human transform growth factor-β1(rhTGF-β1) and potential mechanism. Methods:HLFs were cultured and divided into six groups:the control group,the TGF-β1-treated group(5 ng/mL),the TGF-β1 plus 0.01,0.10,1.00 nmmol/L paclitaxel group and the paclitaxel-only(1 nmol/L)group. Cell viability was measured by CCK8 assay. Cell morphology changes were observed and analyzed by microscope. Transwell assay was carried out to assess cell migration. Immunofluorescence was employed to detect the expression of α-SMA. The levels of α-SMA,fibronectin,collagenⅠ,collagen Ⅲ were detected by real-time PCR and Western blot. The protein levels of phospho-Smad3,Smad3,phospho-p38 and p38 in cells were determined by Western blot. Results:The results of CCK8 showed that 1 nmol/L PTX had no toxic effect on HLFs,0.01 nmol/L PTX could not inhibit the cell viability of HLFs induced by TGF-β1,and 0.1,1.0 nmol/L PTX could inhibit the cell viability of HLFs induced by TGF-β1;The results of cell morphology showed that 0.01 nmol/L PTX could not reduce the width of HLFs induced by TGF-β1,and 0.1,1.0 nmol/L PTX could reduce the width of HLFs induced by TGF-β1;The results of transwell assay showed that 0.01 nmol/L PTX could not inhibit the migration of HLFs induced by TGF-β,and 0.1,1.0 nmol/L PTX could inhibit the migration of HLFs induced by TGF-β1;The results of immunofluorescence showed that 0.01 nmol/L PTX could not decrease the fluorescence intensity of α-SMA induced by TGF-β1,and 0.1,1.0 nmol/L PTX could decrease the fluorescence intensity of α-SMA induced by TGF-β1;The results of Real-time PCR and Western blot showed that 0.01 nmol/L PTX could not decrease the content of phenotypic transformation markers such as α-SMA,fibronectin,collagen Ⅰ,collagen Ⅲ and down-regulated the phosphorylation p38,and 0.1,1.0 nmol/L PTX could decrease the content of phenotypic transformation markers such as α-SMA,fibronectin,collagen Ⅰ,collagen Ⅲ,and down-regulated the phosphorylation of Smad3 and p38. Conclusion:PTX inhibited the differentiation of human lung fibroblasts into myofibroblasts induced by TGF-β1 via TGF-β/Smad/MAPK signaling pathway.