Search

Objective To investigate the effect of low-intensity pulsed ultrasound (LIPUS) on the extracellular matrix synthesis of human osteoarthritis (OA) chondrocytes and explore the underlying mechanism. Methods Human osteoarthritis chondrocytes were collected from abandoned articular cartilage. Then the cells were cultured and identified by toluidine blue staining and immunocytochemical staining of type 2 collagen. The passage 2 cells were randomly divided into 3 groups: control OA group, 30 mW/cm 2 LIPUS-treated OA group, 30 mW/cm 2 LIPUS combined with 5 μmol/L LY294002-treated OA group. LIPUS treatment was performed for 20 minutes per day, totally 7 days. The mRNA levels of Col2, aggrecan and matrix metalloprotease 13 (MMP-13) were determined by quantitative real-time PCR. The protein levels of Col2, aggrecan, Akt, p-Akt and MMP-13 were evaluated by Western blotting. Results Compared with the control OA group, the expressions of Col2 and aggrecan at both mRNA and protein levels significantly increased, and MMP-13 significantly reduced in the LIPUS-treated OA group. The p-Akt protein level was significantly elevated after LIPUS stimulation, but there was no significant difference in the Akt protein levels between the two groups. Moreover, LY294002, an inhibitor of PI3K/Akt, significantly suppressed the biological effect activated by LIPUS. Conclusion LIPUS enhances the synthesis and inhibits the degradation of the extracellular matrix in human osteoarthritis chondrocytes.

Objective: To investigate the effect of linear polarized infrared light irradiation on the proliferation of primary cultured rabbit articular chondrocytes irradiation., Methods: Primary cultured rabbit articular chondrocytes were irradiated with linear polarized infrared light irradiation (Super Lizer) at the power intensity of 20% (360 mW) to 100% (1800 mW) for 5 min per day for 5 days, and CCK-8 assay was used to measure the proliferative activity of the chondrocytes after the exposures., Results: The D(450) values of the cells irradiated at the power intensity of 60% (1080 mW) and 80% (1440 mW) (1.88∓0.11 and 1.99∓0.05, respectively) were significantly greater than that of the control cells (0.95∓0.38, P<0.05). The irradiation with Super Lizer at lower (20%, 360 mW and 40%, 720 mW) or higher (100%, 1800 mW) power intensities did not cause significant increases of the D(450) values. Compared with the control group, Super Lizer irradiation at the power intensities of 20%, 40%, 60%, and 80% resulted in increment ratios of chondrocyte viability of (48.75∓15.4 )%, (67.02∓29.61)%, (97.93∓11.57)%, and (108.52∓5.81)%, respectively, but at 100% power intensity (1800 mW), the irradiation caused a lowered chondrocyte viability increment ratio of (62.84∓31.12)%., Conclusion: Linear polarized infrared light irradiation can promote the proliferation of chondrocytes in an intensity-dependent manner, and the strongest effect occurs with the irradiation power intensity of 80% (1440 mW).