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Cyclic loading increases friction and changes cartilage surface integrity in lubricin-mutant mouse knees

OBJECTIVE: To investigate the effects of lubricin gene dosage and cyclic loading on whole joint coefficient of friction and articular cartilage surface integrity in mouse knee joints. METHODS: Joints from mice with 2 (Prg4(+/+)), 1 (Prg4(+/−)), or no (Prg4(−/−)) functioning lubricin alleles were sub...

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Autores principales: Drewniak, Elizabeth I, Jay, Gregory D, Fleming, Braden C, Zhang, Ling, Warman, Matthew L, Crisco, Joseph J
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Wiley Subscription Services, Inc., A Wiley Company 2012
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Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3252402/
https://www.ncbi.nlm.nih.gov/pubmed/21905020
http://dx.doi.org/10.1002/art.33337
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author Drewniak, Elizabeth I
Jay, Gregory D
Fleming, Braden C
Zhang, Ling
Warman, Matthew L
Crisco, Joseph J
author_facet Drewniak, Elizabeth I
Jay, Gregory D
Fleming, Braden C
Zhang, Ling
Warman, Matthew L
Crisco, Joseph J
author_sort Drewniak, Elizabeth I
collection PubMed
description OBJECTIVE: To investigate the effects of lubricin gene dosage and cyclic loading on whole joint coefficient of friction and articular cartilage surface integrity in mouse knee joints. METHODS: Joints from mice with 2 (Prg4(+/+)), 1 (Prg4(+/−)), or no (Prg4(−/−)) functioning lubricin alleles were subjected to 26 hours of cyclic loading using a custom-built pendulum. Coefficient of friction values were measured at multiple time points. Contralateral control joints were left unloaded. Following testing, joints were examined for histologic evidence of damage and cell viability. RESULTS: At baseline, the coefficient of friction values in Prg4(−/−) mice were significantly higher than those in Prg4(+/+) and Prg4(+/−) mice (P < 0.001). Cyclic loading continuously increased the coefficient of friction in Prg4(−/−) mouse joints. In contrast, Prg4(+/−) and Prg4(+/+) mouse joints had no coefficient of friction increases during the first 4 hours of loading. After 26 hours of loading, joints from all genotypes had increased coefficient of friction values compared to baseline and unloaded controls. Significantly greater increases occurred in Prg4(−/−) and Prg4(+/−) mouse joints compared to Prg4(+/+) mouse joints. The coefficient of friction values were not significantly associated with histologic evidence of damage or loss of cell viability. CONCLUSION: Our findings indicate that mice lacking lubricin have increased baseline coefficient of friction values and are not protected against further increases caused by loading. Prg4(+/−) mice are indistinguishable from Prg4(+/+) mice at baseline, but have significantly greater coefficient of friction values following 26 hours of loading. Lubricin dosage affects joint properties during loading, and may have clinical implications in patients for whom injury or illness alters lubricin abundance.
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spelling pubmed-32524022012-11-09 Cyclic loading increases friction and changes cartilage surface integrity in lubricin-mutant mouse knees Drewniak, Elizabeth I Jay, Gregory D Fleming, Braden C Zhang, Ling Warman, Matthew L Crisco, Joseph J Arthritis Rheum Osteoarthritis OBJECTIVE: To investigate the effects of lubricin gene dosage and cyclic loading on whole joint coefficient of friction and articular cartilage surface integrity in mouse knee joints. METHODS: Joints from mice with 2 (Prg4(+/+)), 1 (Prg4(+/−)), or no (Prg4(−/−)) functioning lubricin alleles were subjected to 26 hours of cyclic loading using a custom-built pendulum. Coefficient of friction values were measured at multiple time points. Contralateral control joints were left unloaded. Following testing, joints were examined for histologic evidence of damage and cell viability. RESULTS: At baseline, the coefficient of friction values in Prg4(−/−) mice were significantly higher than those in Prg4(+/+) and Prg4(+/−) mice (P < 0.001). Cyclic loading continuously increased the coefficient of friction in Prg4(−/−) mouse joints. In contrast, Prg4(+/−) and Prg4(+/+) mouse joints had no coefficient of friction increases during the first 4 hours of loading. After 26 hours of loading, joints from all genotypes had increased coefficient of friction values compared to baseline and unloaded controls. Significantly greater increases occurred in Prg4(−/−) and Prg4(+/−) mouse joints compared to Prg4(+/+) mouse joints. The coefficient of friction values were not significantly associated with histologic evidence of damage or loss of cell viability. CONCLUSION: Our findings indicate that mice lacking lubricin have increased baseline coefficient of friction values and are not protected against further increases caused by loading. Prg4(+/−) mice are indistinguishable from Prg4(+/+) mice at baseline, but have significantly greater coefficient of friction values following 26 hours of loading. Lubricin dosage affects joint properties during loading, and may have clinical implications in patients for whom injury or illness alters lubricin abundance. Wiley Subscription Services, Inc., A Wiley Company 2012-02 /pmc/articles/PMC3252402/ /pubmed/21905020 http://dx.doi.org/10.1002/art.33337 Text en Copyright © 2012 by the American College of Rheumatology http://creativecommons.org/licenses/by/2.5/ Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.
spellingShingle Osteoarthritis
Drewniak, Elizabeth I
Jay, Gregory D
Fleming, Braden C
Zhang, Ling
Warman, Matthew L
Crisco, Joseph J
Cyclic loading increases friction and changes cartilage surface integrity in lubricin-mutant mouse knees
title Cyclic loading increases friction and changes cartilage surface integrity in lubricin-mutant mouse knees
title_full Cyclic loading increases friction and changes cartilage surface integrity in lubricin-mutant mouse knees
title_fullStr Cyclic loading increases friction and changes cartilage surface integrity in lubricin-mutant mouse knees
title_full_unstemmed Cyclic loading increases friction and changes cartilage surface integrity in lubricin-mutant mouse knees
title_short Cyclic loading increases friction and changes cartilage surface integrity in lubricin-mutant mouse knees
title_sort cyclic loading increases friction and changes cartilage surface integrity in lubricin-mutant mouse knees
topic Osteoarthritis
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3252402/
https://www.ncbi.nlm.nih.gov/pubmed/21905020
http://dx.doi.org/10.1002/art.33337
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