【Animal modeling】-Lipopolysaccharide-induced knee joint fibroblast-like synovial cell inflammation model in SD rats and analysis of its characteristics

  Objective To establish a primary culture method of normal knee synovial cells in (SD) rats and a lipopolysaccharide-induced fibroblast-like synovial cell inflammation model.

  Methods 80-120 g SPF juvenile SD rats were selected, their synovial tissue was isolated, and primary cultured to the third passage. The FLS protein marker vimentin and proliferation function were detected by histochemical staining method and EdU method. At the same time, synovial tissue was used as a control to detect the expression of characteristic proteins of FLS from the third to eighth passages, and to screen high-purity FLS cells with physiological functions that could be used in subsequent experiments. After LPS-induced FLS inflammation, the mRNA and protein expressions of IL-1β and TNF-α at different time points were detected, and the time points when LPS successfully induced the FLS inflammation model were determined according to the experimental results. Finally, the expression of cytokines, proliferation functions and characteristic proteins before and after induction of FLS by LPS were detected, which provided experimental data for analyzing the inflammation model of FLS.

  Results FLS primary cells were successfully cultured by 0.2% collagenase type I digestion method. After the detection of the protein marker vimentin, the purity of the third-generation FLS was over 98%. Through the detection of FLS characteristic protein, the FLS with physiological function and can be used for subsequent experiments were screened as the 3rd to 7th generation primary cells. By analyzing the cytokines and characteristic proteins of FLS induced by LPS, it was determined that 1μg/mL LPS induced FLS cells for 3h, and the FLS inflammation model could be replicated.

  Conclusion The LPS-induced FLS inflammatory model can be used as a cellular model for the study of inflammatory joint disease in vitro.