Abstract:

Objective To investigate the effect of bone marrow mesenchymal stem cells （BMSCs） on the proliferation and collagen expression levels of L929 cells， and to clarify its related mechanism. Methods The BMSCs were extracted from the 4-week-old C57BL/6 mice. The phenotypes of BMSCs were identified by immunofluorescence staining. The L929 cells were divided into control group （L929 cells）， co-culture group （L929 cells and BMSCs）， inhibitor of Janus kinase（JAK） WP1066 group （WP1066-treated L929 cells and BMSCs）， and dimethyl sulfoxide （DMSO） group （DMSO-treated L929 cells and BMSCs）. Cell counting kit-8 （CCK-8） assay was used to detect the proliferation activities of the L929 cells in various groups at different time points； Western blotting method was used to detect the expression levels of type Ⅰ collagen （ColⅠ） and type Ⅲ collagen （ColⅢ） in the L929 cells in various groups； immunofluorescence staining was used to detect the expressions of ColⅠ and ColⅢ proteins in the L929 cells in various groups. Results The fluorescence assay results of surface antigen（SA） showed that the surface markers CD29+， CD45-， CD90+ and CD105+ were found in the BMSCs. The CCK-8 assay results showed that compared with control group， the proliferation activities of the L929 cells in co-culture group and DMSO group were significantly increased（P<0.01）； compared with co-culture group， the proliferation activity of the L929 cells in WP1066 group was significantly decreased （P<0.01）. The Western blotting method results showed that compared with control group， the expression levels of ColⅠ and ColⅢ proteins in the L929 cells in co-culture group and DMSO group were significantly increased （P<0.01）； compared with co-culture group， the expression levels of ColⅠ and ColⅢ proteins in the L929 cells in WP1066 group were significantly decreased （P<0.01）； compared with DMSO group， the expression levels of ColⅠ and ColⅢ proteins in the L929 cells in WP1066 group were significantly decreased （P<0.01）. The immunofluorescence staining results showed that compared with control group， the fluorescence intensities of ColⅠ and ColⅢ proteins in the L929 cells in co-culture group and DMSO group were significantly increased（P<0.01）； compared with co-culture group， the fluorescence intensities of ColⅠ and ColⅢ in the L929 cells in WP1066 group were significantly decreased（P<0.01）； compared with DMSO group， the fluorescence intensities of ColⅠ and ColⅢ in the L929 cells in WP1066 group were significantly decreased （P<0.01）. Conclusion MSCs can promote the proliferation and collagen production of the L929 cells of the mice through the JAK2/signal transducer and activator of transcription 3（STAT3） signaling pathway.

Key words: Pelvic floor dysfunction, Bone marrow mesenchymal stem cell, Fibroblast, Type Ⅰ collagen, Type Ⅲ collagen, Janus kinase 2, Signal transducer and activator of transcription 3