ABSTRACT
OBJECTIVE@#To investigate the effect and mechanism of mechanical stress on cartilage repair in inflammatory environment.@*METHODS@#The chondrogenic progenitor cells (CPCs) were isolated from the knee joint cartilage of patients with osteoarthritis (OA) undergoing total knee arthroplasty. The CPCs were cultured and expanded in a 3-D scaffold constructed with alginate. Intermittent hydrostatic pressure (IHP) was applied in a inflammatory environment induced by IL-1β, and Western blot was used to detect the expression of MAPK signaling pathway proteins. Cell proliferation was detected by CCK-8 method, and the expression of related genes like matrix metallo-proteinases 13 (MMP-13) and a disintegrins and metalloproteinase with thrombospondin motif 5 (ADAMTS-5) was detected by real-time RT-PCR. The anterior cruciate ligament of the rats was cut to construct the knee joint OA model, and the appropriate mechanical stress was constructed with external fixation to distract the knee joint in order to observe the repair of the cartilage and to explore its mechanism.@*RESULTS@#Adding 0.01 ng/ml IL-1β in cell culture inhibited the proliferation of CPCs. After IHP application, the expression of MAPK pathway protein was decreased, the mRNA expression of MMP-13 and ADAMTS-5 was reduced. The inhibition of IL-1β on CPCs was counteracted by IHP. Four weeks after the anterior cruciate ligament resected, the articular cartilage degeneration was observed in rats. The Mankin score in the OA treatment (joint distraction) group was lower, and the cartilage repair was better than that of the control group (<0.01). Animal experiments found that the suitable mechanical stress reduced the expression of P-p38, MMP-13 and COLL-X, inhibited cartilage cells apoptosis and promoted the repair of OA cartilage.@*CONCLUSIONS@#Mechanical stress can promote the proliferation of CPCs, reduce the expression of matrix degrading enzymes, and promote the repair of OA cartilage by inhibiting MAPK signaling pathway.
Subject(s)
Animals , Humans , Rats , Anterior Cruciate Ligament , Pathology , General Surgery , Cartilage, Articular , Pathology , Cells, Cultured , Chondrocytes , Cell Biology , Disease Models, Animal , Gene Expression Profiling , Mitogen-Activated Protein Kinases , Genetics , Osteoarthritis , Pathology , Polymerase Chain Reaction , Signal Transduction , Genetics , Stress, MechanicalABSTRACT
Objective To investigate the effects on IL-6 and PGE2 expression in wear-particles-induced osteoblast cells by blocking calcium phosphatase (Cn)/ activated T nuclear factor (NFAT) pathway. Methods Fetal Sprague-Dawley rats were used in this study. Osteoblast were prepared from the calvariae of rats . Osteoblast cells were incubated in four group according to different supplementation:(1) neither Ti particles nor 11R-VIVIT (Control group), (2) only Ti particles (Ti group), (3) both Ti particles and 11R-VIVIT (Ti/VIVIT group), and (4) only 11R-VIVIT (VIVIT group). Cells were incubated for 96 hours and the expression of NFATc1 protein was detected by western blot. The expression of IL-6 and PGE2 in liquid supernatant of osteoblast were detected at 6, 24 and 96 hours by ELISA. Results The expression of NFATc1 in the Ti group was higher than that in the Control group (P < 0.01), but in Ti/VIVIT group that was significantly lower than in the titanium particle group (P < 0.01). The IL-6 and PGE2 expression in the supernatant of the Ti group were significantly increased than those in the control group (P < 0.05). The IL-6 and PGE2 in the Ti/VIVIT group were significantly lower than that in the Ti group (P < 0.05). Conclusions 11R-VIVIT peptide specific blockade of Cn/NFAT signaling pathway significantly inhibited IL-6 and PGE2 of osteoblast cells induced by titanium particles.