Effect of Micro-strain Stress on in Vitro Proliferation and Functional Expression of Human Osteoarthritic Chondrocytes

Background: This study aimed to analyze the in vitro effect of micro-strain stress on the proliferation and functional marker expression in chondrocytes isolated from human osteoarthritis cartilage samples.Methods: Chondrocytes isolated from human osteoarthritis cartilage samples were subjected to loading with different types of micro-strain stress. The proliferation activity was assessed by flow cytometry, and the functional expression of chondrocyte markers was detected by qRT-PCR and western blot. Results: Flow cytometry results showed stimulation of proliferation of human osteoarthritic chondrocytes when an adequate micro-strain stress was applied. qRT-PCR and western blot results showed that micro-strain stress promotes human osteoarthritic chondrocyte functional marker expression. These features coincide with the upregulation of multiple proteins and genes affecting cell proliferation and functional chondrocyte marker expression, including cyclin D1, collagen II, and Rock.Conclusion: Adequate micro-strain stress could activate the Rho/Rock signaling pathway in osteoarthritic chondrocytes, thus transmitting mechanical signals to the cytoskeleton. This process leads to cytoskeleton reorganization, and transmission of the mechanical signals to the downstream effectors to promote proliferation and functional marker expression of osteoarthritic chondrocytes.

Influence of different sized nanoparticles combined with ultrasound on the optical properties of in vitro knee joint and knee osteoarthritis cartilage tissue was studied by OCT and diffuse reflectance spectroscopy

The penetration and accumulation of zinc oxide nanoparticles (ZnO NPs) with different sizes in human normal knee joint (NKJ) tissue and knee osteoarthritis (OA) tissue were studied by continuous optical coherence tomography and diffuse reflectance (DR) spectroscopy in this paper, and the effects of ZnO NPs of two sizes (30 nm and 90 nm) and ultrasound (US) on the optical properties of human NKJ and OA tissue were evaluated. The results show that the average attenuation coefficients of NKJ tissue decrease by 14.90%, 26.91%, 33.52% and 37.01%, and the DR spectra increases by 8.444%, 12.901%, 18.219% and 26.125%, respectively, after being treated with 90 nm ZnO NPs, 90 nm ZnO NPs/US, 30 nm ZnO NPs and 30 nm ZnO NPs/US. The average attenuation coefficients of OA tissue are reduced by 32.14%, 49.51%, 57.85% and 72.30%, and the DR spectra increase by 17.426%, 23.116%, 25.218% and 29.326%, respectively, after being treated with 90 nm ZnO NPs, 90 nm ZnO NPs/US, 30 nm ZnO NPs and 30 nm ZnO NPs/US. It is concluded that the optical properties of NKJ and OA tissues are greatly influenced by ZnO NPs and US. Nanoparticles have a greater impact on OA tissue than on NKJ tissue.

Effect of Tobacco on Knee Joint Recovery of College Students After Sports

Objectives: By analyzing the protective effect and mechanism of tobacco on knee joint cartilage in rats, this paper studies the effect of tobacco on knee joint recovery of college students after sports. Methods: Firstly, the main subunits of nAChRs were systematically studied by using the rat knee arthritis model α 7 and α 4 and β To clarify the correlation between nAChRs and the occurrence and development of OA. Then, the OA rat model prepared by iodoacetic acid was used as the experimental object to observe the protective effect of nicotine on knee osteoarthritis cartilage in rats. Results: The histological changes of rats in MIA group were obvious after operation. The results of light microscope score and Mankin's score at 15 and 30 days were significantly higher than those in con group. Of right knee cartilage in rats in MIA group α 7, α 4 and β The expression of 2 did not change significantly on the 15th day, but increased significantly on the 30th day compared with the blank control group. Conclusion: Nicotine has a protective effect on knee bone and joint cartilage and promotes the accelerated recovery of knee bone and joint after exercise.. Key words: nicotine, knee joint, cartilage, recovery after exercise.

Decreased Sulfate Content and Zeta Potential Distinguish Glycosaminoglycans of the Extracellular Matrix of Osteoarthritis Cartilage

We aimed to determine the characteristics that distinguish glycosaminoglycans (GAGs) from osteoarthritis (OA) and normal cartilage and from men and women. Cartilage samples from 30 patients subjected to total joint arthroplasty secondary to OA or fracture (control) were evaluated, and the GAG content (μg/mg dry cartilage) after proteolysis was determined by densitometry, using agarose-gel electrophoresis. Relative percentages of carbon (C), nitrogen (N), and sulfur (S) in GAGs were determined by elemental microanalysis, as well as the zeta potential. Seventeen samples (56.6%) were from patients >70 years old, with 20 (66.6%) from women, and most [20 (66.6%)] were from the hip. The GAG content was similar regardless of patients being >/≤ 70 years old with 96.5 ± 63.5 and 78.5 ± 38.5 μg/mg (P = 0.1917), respectively. GAG content was higher in women as compared to men, with 89.5 ± 34.3 and 51.8 ± 13.3 μg/mg, respectively (P = 0.0022), as well as in OA than fracture samples, with 98.4 ± 63.5 and 63.6 ± 19.6 μg/mg, respectively (P = 0.0355). The GAG extracted from the cartilage of patients >70 years old had increase in N, and there were no gender differences regarding GAG elemental analysis. GAG from OA had a highly significant (P = 0.0005) decrease in S% (1.79% ± 0.25%), as compared to fracture samples (2.3% ± 0.19%), with an associated and significant (P = 0.0001) reduction of the zeta potential in the OA group. This is the first report of a reduced S content in GAG from OA patients, which is associated with a reduced zeta potential.