Objective: To investigate the role of p38 MAPK pathway in IL-1β induced inflammatory secretory properties mesenchymal stem cells(SFMSCs) from human synovial fluid of temporomandibular joint. Methods: In vitro cultured hSFMSCs were divided into control group and IL-1β treated group(10 ng/ml IL-1β for 2 h), the activation of p38 MAPK was examined with western blot. Then, the gene expression and the secretion of IL-6 and IL-8 in control group, IL-1β treated group and p38 MAPK inhibitor pre-treated group(pretreatment with SB-203580 10 μmol/L prior to the addition of 10 ng/ml IL-1β) were examined by RT-PCR and cytometric bead array(CBA). Results: It was observed that the protein level of p-p38 MAPK, the secretion of IL-8 and IL-6 were increased in IL-1β treated group, and suppressed in p38 MAPK inhibitor pre-treated group. Conclusion: p38 MAPK pathway of SFMSCs might play a role in IL-6 and IL-8 secretion by SFMSCs in inflammatory environment.

Objective: This study investigated the effects of interleukin-1β (IL-1β) on human synovial fluid-derived mesenchymal stem cells (hSFMSCs) in the temporomandibular joint. Methods : hSFMSCs from synovial fluid samples of temporomandibular disorder (TMD) patients were cultured in vitro. hSFMSCs were divided into three groups with different concentrations of rhIL-1β in complete medium (α-MEM cell culture medium + 10% FBS + 1× GlutaMAX): 0 ng/mL IL-1β group, 1 ng/mL IL-1β group and 10 ng/mL IL-1β group. Changes in the rate of colony formation, growth curve, cell cycle and apoptosis of hSFMSCs under IL-1β stimulation were evaluated. The osteogenic, adipogenic and chondrogenic potential of the cells were also determined using histochemical and real-time fluorescence quantitative PCR methods. Results : No significant differences in growth or proliferation capacity were observed in any IL-1β-stimulated group in comparisons of the colony-formation rate (F = 0.665, P=0.548), growth curve (F=0.001, P=0.999), cell cycle (FG1=0.773, PG1=0.503; FS =0.636, PS =0.562) or apoptosis (F=0.196, P=0.827) of the cells. However, the multidifferentiation capacity of hSFMSCs was affected in the inflammatory environment. Mineralized nodule and lipid clusters decreased significantly, and the gene expression levels of runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), peroxisomal proliferative receptor G2 (PPARG2) and lipoprotein lipase (LPL) were suppressed significantly in IL-1β-mediated induction medium (P < 0.05). In general, cartilage pellets formed in all the IL-1β-mediated chondrogenic differentiation groups. The gene levels of sex-determining region Y-related high-mobility group box-9 (SOX9) and collagen II were decreased (P < 0.05), while that of matrix metalloproteinase 13 (MMP13) was increased significantly in the presence of IL-1β (P < 0.05). Conclusion IL-1β directly affects the multidifferentiation potential of hSFMSCs but not their cell growth or proliferation ability.

Objective: To analyze related factors on the number of mesenchymal stem cells in the synovial fluid of the temporomandibular joint (TMJ) and provide an research basis for understanding of the source and biological role of mesenchymal stem cells derived from synovial fluid in TMJ. Methods: One hundred and twenty-two synovial fluid samples from 91 temporomandibular disorders (TMD) patients who visited in Department of TMJ Center, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University from March 2013 to December 2013 were collected in this study, and 6 TMJ synovial fluid samples from 6 normal volunteers who were studying in the North Campus of Sun Yat-sen University were also collected, so did their clinical information. Then the relation between the number of mesenchymal stem cells derived from synovial fluid and the health status of the joints, age of donor, disc perforation, condylar bony destruction, blood containing and visual analogue scale score of pain were investigated using Mann-Whitney U test and Spearman rank correlation test. Results: The number of mesenchymal stem cells derived from synovial fluid had no significant relation with visual analogue scale score of pain (r=0.041, P=0.672), blood containing (P=0.063), condylar bony destruction (P= 0.371). Linear correlation between the number of mesenchymal stem cells derived from synovial fluid and age of donor was very week (r=0.186, P=0.043). The number of mesenchymal stem cells up-regulated when the joint was in a disease state (P=0.001). The disc perforation group had more mesenchymal stem cells in synovial fluid than without disc perforation group (P=0.042). Conclusions The number of mesenchymal stem cells derived from synovial fluid in TMJ has no correlation with peripheral blood circulation and condylar bony destruction, while has close relation with soft tissue structure damage of the joint.