ABSTRACT
Lubricin is widely expressed in tissues in the musculoskeletal system, including articulate cartilage, tendon and synovium, which shows a close relationship with the structure and pathology of these tissues. Lubricin plays an important role in lubrication, anti-adhesion, proliferation inhibition and inflammation regulation, which may facilitate the healing of impaired tissues in the musculoskeletal system. This article reviews the research progress on expression and regulation of lubricin as well as its structure and function in wound repair of the musculoskeletal system, so as to provide theoretical evidences for further researches on the role of lubricin in the musculoskeletal system with its related mechanisms and the clinical application of lubricin.
ABSTRACT
Objective To investigate the effect of needle-warmed moxibustion on chondrocyte apoptosis and the lubricin protein content of osteoarthritic knees.Methods Forty New Zealand white rabbits were randomly divided into a sham operation group,a model group,a Western medicine group and a needle-warmed moxibustion group,each of 10.Knee osteoarthritis was induced in all except the sham operation group by injecting an aqueous solution of papain into the outer edge of one patellar tendon at the inferior pole of the patella.In the sham operation group the injection needle was only inserted and withdrawn.The needle-warmed moxibustion group had needle-warmed moxibustion applied to the internal and external DUBI acupoints 14 days after the modelling in 2 courses of treatment.The Western medicine group was given diclofenac sodium (15 mg/kg body weight) by gavage on the same schedule.The sham operation group and the model group were fed normally without special treatment.At the end of the treatment,knee cartilage tissue was resected from each group and the number of chondrocytes and the expression of lubricin in the articular cartilage cells were compared.Results Compared with the model group and the Western medicine group,the number of chondrocytes in the moxibustion group was significantly greater and the cells were arranged more neatly.TUNEL staining showed that the apoptosis rate of chondrocytes in the moxibustion group was significantly lower.A reverse transcription polymerase chain reaction showed that the expression of lubricin mRNA in the moxibustion group had increased significantly.Western blotting showed that the expression of lubricin protein was also significantly enhanced in the moxibustion group.Conclusions Needle-warmed moxibustion has a positive therapeutic effect on knee osteoarthritis,at least in rabbits.It can inhibit the apoptosis of knee chondrocytes and promote the secretion of lubricin.
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Objective To investigate the effects of vitamin D on synthesis and secretion of lubricin in chondrocytes at the cellular level. Methods Rat articular chondrocytes were stimulated by TNF-α. Normal and inflammatory chondrocytes were treated by different doses of vitamin D respectively. ELISA and Western Blot were used to detect the secretion of lubricin in the supernatant and the synthesis level in the cells. Results TNF-α significantly reduced the activity of both normal chondrocytes and chondrocytes in inflammatory state. TNF-α also significantly reduced the expression of lubricin in the cells and supernatant. 1α,25(OH)2D3 increased the activity of both normal chondrocytes and chondrocytes in inflammatory state. 1α,25(OH)2D3 significantly elevated the secretion and expression of supernatant and intracellular lubricin only in chondrocytes stimulated by TNF-α in a dose-dependent manner, but not in normal chondrocytes. Conclusions Vitamin D can promote the secretion and expression of lubricin in inflammatory state chondrocytes, which may act as one of the mechanisms of vitamin D protecting the cartilage surface in osteoarthritis.
ABSTRACT
Objective To investigate the effects of vitamin D on synthesis and secretion of lubricin in chondrocytes at the cellular level. Methods Rat articular chondrocytes were stimulated by TNF-α. Normal and inflammatory chondrocytes were treated by different doses of vitamin D respectively. ELISA and Western Blot were used to detect the secretion of lubricin in the supernatant and the synthesis level in the cells. Results TNF-α significantly reduced the activity of both normal chondrocytes and chondrocytes in inflammatory state. TNF-α also significantly reduced the expression of lubricin in the cells and supernatant. 1α,25(OH)2D3 increased the activity of both normal chondrocytes and chondrocytes in inflammatory state. 1α,25(OH)2D3 significantly elevated the secretion and expression of supernatant and intracellular lubricin only in chondrocytes stimulated by TNF-α in a dose-dependent manner, but not in normal chondrocytes. Conclusions Vitamin D can promote the secretion and expression of lubricin in inflammatory state chondrocytes, which may act as one of the mechanisms of vitamin D protecting the cartilage surface in osteoarthritis.