Analysis of microarchitectural changes in a mouse temporomandibular joint osteoarthritis model.
OBJECTIVE
Little is known about the natural progression of the disease process of temporomandibular joint (TMJ) osteoarthritis (OA), which affects approximately 1% of the US population. The goal of this study was to examine the early microarchitectural and molecular changes in the condylar cartilage and subchondral bone in biglycan/fibromodulin (Bgn/Fmod) double-deficient mice, which develop TMJ-OA at 6 months.


METHODS
TMJs from 3-month-old (n=44) and 9-month-old (n=52) wild-type (WT n=46) and Bgn/Fmod (n=50) double-deficient mice were evaluated. Micro-CT analysis of the subchondral bone (n=24), transmission electron microscopy for condylar cartilage fibril diameters (n=26), and real-time PCR analysis for gene expression for bone and cartilage maturation markers (n=45) was performed.


RESULTS
A statistically significant increase in collagen fibril diameter of the condylar cartilage and a decrease in expression of Parathyroid related protein in the mandibular condylar head were observed in the 3-month Bgn/Fmod double-deficient mice compared to WT controls. The 9-month Bgn/Fmod double-deficient mouse demonstrated an increase in bone volume and total volume in subchondral bone, and an increase in the expression of Collagen Type X and Aggrecan in the mandibular condylar head compared to the WT controls.


CONCLUSIONS
We found that changes in the microarchitecture of the condylar cartilage preceded changes in the subchondral bone during OA in the TMJ in Bgn/Fmod double-deficient mice.
Chen
J
J
University of Connecticut Health Center, Department of Craniofacial Sciences, Farmington, 06030, United States.
Gupta
T
T
Barasz
J A
JA
Kalajzic
Z
Z
Yeh
W-C
WC
Drissi
H
H
Hand
A R
AR
Wadhwa
S
S
D053674:Aggrecans / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D058578:Biglycan; D002358:Cartilage, Articular / Q000473:pathology; D024121:Collagen Type X / Q000096:biosynthesis / Q000235:genetics; D004195:Disease Models, Animal; D016326:Extracellular Matrix Proteins / Q000172:deficiency*; D000071235:Fibromodulin; D015870:Gene Expression; D008335:Mandibular Condyle / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D018345:Mice, Knockout; D046529:Microscopy, Electron, Transmission; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology*; D044162:Parathyroid Hormone-Related Protein / Q000096:biosynthesis / Q000235:genetics; D011509:Proteoglycans / Q000172:deficiency*; D013705:Temporomandibular Joint Disorders / Q000378:metabolism / Q000473:pathology*; D055114:X-Ray Microtomography
D053674:Aggrecans; C546885:Bgn protein, mouse; D058578:Biglycan; D024121:Collagen Type X; D016326:Extracellular Matrix Proteins; C000604332:Fmod protein, mouse; D044162:Parathyroid Hormone-Related Protein; D011509:Proteoglycans; D000071235:Fibromodulin