ObjectiveTo study the potential protective effects of bone marrow mesenchymal stem cells (BMSCs) on chondrocytes injured by interleukin 1β (IL-1β), and the resistant capacity of chondrocytes when co-cultured indirectly with BMSCs against IL-1β. MethodsSix Sprague Dawley (SD) rats were randomly divided into experimental group (articular cartilage defects) and control group. The content and gene expression of IL-1β were detected at 6 hours after surgical intervention by quantitative real time RCR (qRT-PCR) and ELISA. BMSCs repairing function test: the 18-holes cultured chondrocytes were randomly divided into 3 groups (n=6): cells of blank group were not treated;cells of injured group and co-cultured group were intervened by IL-1β, and Transwell chamber was used to establish co-culture system of BMSCs with chondrocyte in co-cultured group. The mRNA relative expressions of cysteinyl aspartate specific proteinase 3 (Caspase 3), a disintegrin and metalloprotease with Thrombospondin motifs 4 (ADAMTS-4), and ADAMTS-5 were measured via qRT-PCR in chondrocytes, meanwhile Caspase-3 content was detected via ELISA, and the cell apoptosis rate was detected via flow cytometry. BMSCs protecting function test: the 12-holes cultured chondrocytes were randomly divided into 2 groups (n=6), Transwell chamber was used to establish co-culture system of BMSCs with chondrocyte in co-cultured group before the 2 groups were both intervened by IL-1β, then the same detected indexes were taken as the BMSCs repairing function test. ResultsAnimal in vivo studies showed that relative expression of IL-1β mRNA and IL-1β contents were significantly higher in experimental group than control group (P<0.05). BMSCs repair tests showed that mRNA relative expressions of Caspase-3, ADAMTS-4, and ADAMTS-5, Caspase-3 content, and cell apoptosis rate were significantly higher in injured group and co-cultured group than blank group, and in injured group than co-cultured group (P<0.05). BMSCs protect tests showed that mRNA relative expressions of Caspase-3, ADAMTS-4, and ADAMTS-5, Caspase-3 content, and cell apoptosis rate in co-cultured group were significantly lower than those in control group (P<0.05). ConclusionBMSCs, as seed cells for tissue engineering, have potential for applications to anti-inflammation and anti-apoptosis.