ObjectiveTo investigate the effect of inhibiting autotaxin (ATX)-lysophosphatidic acid (LPA) pathway on the cartilage of knee osteoarthritis in rats.MethodsPrimary chondrocytes within three generations of Sprague-Dawley rats (8 weeks old, male) were randomly divided into 6 groups, including blank control group, model group, 1 μmol/L PF-8380 group, 10 μmol/L PF-8380 group, 1 μmol/L Ki16425 group, and 10 μmol/L Ki16425 group. Except for the blank control group, the other groups were modeled with osteoarthritis using interleukin-1β (10 ng/mL, 24 h), and then the experimental groups, i.e., 1 μmol/L PF-8380 group, 10 μmol/L PF-8380 group, 1 μmol/L Ki16425 group, and 10 μmol/L Ki16425 group, were intervened with 1, 10 μmol/L PF-8380 (ATX inhibitor) and 1, 10 μmol/L Ki16425 (LPA receptor antagonist) for 24 h, respectively. immunocytochemistry staining was used to determine the expression of type Ⅱ collagen (Col Ⅱ) in cytoplasm, and Western Blot was used to determine the expression of ATX, LPA, and matrix metalloproteinase-13 (MMP-13) in chondrocytes.ResultsCompared with the blank control group, the average absorbance of Col Ⅱ in chondrocytes in the model group was significantly reduced (0.003 9±0.000 8 vs. 0.110 0± 0.009 0, P<0.05). The expression levels of ATX, LPA, and MMP-13 in chondrocytes in the model group, 1 μmol/L PF-8380 group, 10 μmol/L PF-8380 group, and 1 μmol/L Ki16425 group were significantly higher than those in the blank control group, while the expression levels of ATX, LPA, and MMP-13 in the 10 μmol/L Ki16425 group had no significant difference with those in the blank control group; the expression levels of ATX, LPA, and MMP-13 in the model group, 10 μmol/L PF-8380 group, and 1 μmol/L PF-8380 group decreased in order; the expression levels of ATX, LPA, and MMP-13 in the model group, 1 μmol/L Ki16425 group, and 10 μmol/L Ki16425 group decreased in order.ConclusionInhibiting ATX-LPA pathway may inhibit the up-regulation of MMP-13 levels in articular cartilage of osteoarthritis in rats to reduce the damage of cartilage.
Objective To explore the effects of low-intensity pulsed ultrasound (LIPUS) on anabolism, apoptosis and intraflagellar transport 88 (IFT88) expression in mouse chondrocytes after interleukin (IL)-1β intervention, and the correlation of cartilage repairment by LIPUS with primary cilia. Methods IL-1β intervention, LIPUS intervention and lentiviral carrying IFT88-specifific short hairpin RNA (sh-IFT88) transfection were performed on mouse chondrocytes, respectively. The groups included: normal chondrocyte group (N group), chondrocyte after IL-1β intervention group (OA group), chondrocyte after IL-1β intervention+LIPUS group (OA+U group), sh-IFT88+IL-1β intervention chondrocyte group (KO+OA group), and sh-IFT88+LIPUS+IL-1β treated chondrocyte group (KO+OA+U group). Real-time polymerase chain reaction and immunofluorescence were used to determine the expression of collagen Ⅱ, aggrecan, and primary cilia, and apoptosis was measured by flow cytometry. All experimental data were statistically analyzed using the GraphPad Prism 9.5 software. Results The expression of collagen Ⅱ and aggrecan increased, the apoptosis decreased, and the incidence of primary cilia in chondrocytes of mice increased in the OA+U group compared with those in the OA group (P<0.05). The collagen Ⅱ and aggrecan expression decreased and the apoptosis increased in the KO+OA+U group compared with those in the OA+U group (P<0.05). Conclusion LIPUS can reduce the apoptosis of chondrocytes in C57 mice after IL-1β intervention, and increase the expression of collagen Ⅱ and aggrecan in chondrocyte matrix, and the effect is related to primary cilia.