Low- Level Of Fluid Shear Stress, Inflammatory Factors And P38MAPK Inhibitor For The Influence Of The Chondrocyte Phenotype In An Integrated Microfluidic Device

Popliteal cyst is a general term of popliteal synovial cyst, it is a common orthopedic joint clinicopathologic. In recent years, with the innovation and development of science and technology, rapid changes in surgical treatment of popliteal cyst have occurred. Currently, it has been a mainstream way by using arthroscopic surgery to treat the disease. Compared to the open surgery in the traditional way, arthroscopic treatment has many advantages. This article will select a number of cases to evaluate the treatment and prognosis of popliteal cyst under the arthroscope.Object:Discuss the treatment and prognosis of popliteal cyst under the Arthroscope.Method:Have collected 30 patients who were diagnosed as popliteal cyst after MRI examination from 2013 to 2014. Among them, 20 patients are male, 10 patients are female. The age are from 25 to 65 years old.And the levels of joint pain were various.30 cases of patients with popliteal cysts are unilateral. The cyst communicates with the joint cavity has been determined under the guidance of type-B ultrasonic waves.The assessment of prognosis has been made according to Rauschning and Lindgren ratings.Results:All patients suffered from intra-articular diseases.They all were secondary popliteal cyst, 17 cases were meniscus tear, 9 cases of them were osteoarthritis, and 4were anterior cruciate ligament rupture. There was no phenomena of bleeding, blood vessels or nerve injuries and infection, they all were discharged within three days after surgery. The time of follow-up is 8-24 months,the average is 12 months. Score results of Rauschning and Lindgren ratings:8 preoperative patients are in grade Ⅰ,10 are in gradeⅡ, 12 are in grade Ⅲ. 2cases of postoperative patients are in grade Ⅱ, 1case relapses.Conclusion:The treatment for popliteal cyst under the arthroscope is simple, the operative incision is small and the rehabilitation is easy.Articular cartilage is a hyaline cartilage, which is elastic and can cushion pressure, even has the protective effect on the joint. Trauma, inflammation and other factors can make articular cartilage damaged, which cause cartilage extracellular matrix synthesis and decomposition imbalanced, thus it provides a basis for the occurrence of osteoarthritis. Because articular cartilage has no blood vessel, nerve and lymphatic domination, it cannot regenerate when cartilage is damaged. Articular cartilage is mainly composed of chondrocytes and extracellular matrix. The extracellular matrix contains various collagen and proteoglycan, collagen type 2 is main among them.The collagen type-2 is a articular cartilage-specific collagen of extracellular matrix, occupying more than 90% of the gross. With the increase of generations,density and cultivation time, the expression of collagen type 2 decreased,while collagen type-1 has an opposite effect. In addition, the chondrocytes gradually becomes a long spindlef shape which is different from round or polygonal fibroblast-like initially. Articular cartilage is surrounded by the synovial fluid in physiological conditions.When the joint has a movement, it will produce fluid shear stress. Osteoarthritis is the consequence of the interaction of mechanical and biochemical factors.Therefore, the study of simulating fluid shear stress and the influence for the maintenance of chondrocyte phenotype under complex factors is particularly important.Object:Fluid shear stress is essential for the change of articular cartilage phenotype.In this study, microfluidic chip technology is the basis,we establish aplatform which can generate four different shear stresses in a chip. At the same time,we also joined the cytokine TNF-a and P38 MAPK signal pathway inhibitors to reserch the change of chondrocyte phenotype under the interactions in mechanical and biochemical factors.Method:1.Extract and culture the rat chondrocytes, and identify the primary chondrocytes2.Use soft lithographic technique to make a chip masterplate and use PDMS(Polydimethylsiloxane) to make it into chips. The PDMS chip and glass seal irreversibly after plasma irradiation.3.Use CFD simulation and circuit analogy method to simulate the structure of the chip.4.Use the method of immunofluorescence to stain the chondrocytes influented by shear stess to identify collagen type Ⅰ, collagen type Ⅱ and Glut-1.Results:1.With the fluid shear stress increased,the amount of collagen type-Ⅰexpression increased gradually as well as the dedifferentiation of chondrocytes obviously.2.P38 MAPK signal pathway inhibitors can effectively block the signaling pathway of mechanical force to maintain chondrocyte phenotype.3.TNF-α and fluid shear stress have an effect on the destruction of chondrocyte phenotype.4.Low-flow fluid shear stress play a positive role for the expression of glucose transporter protein-1(Glut-1).Conclusion:Low-flow fluid shear stess for the maintaince of chondrocyte phenotype is a double edged sword, on the one hand, with the increase of shear force,it is capable for specific role of chondrocyte phenotype to maintain. On the other hand, the increase of the shear force also accelerated the dedifferentiation of chondrocytes.P38 MAPK signal pathway inhibitor-SB203580 can inhibit mechanical force signaling pathway, and block the shear force for the maintenance of chondrocyte phenotype and dedifferentiation role. Inflammatory cytokines TNF-α for the maintaince of chondrocyte phenotype plays a negative role.