Quantitative histological changes of repeated antigen-induced arthritis in the temporomandibular joints of rabbits treated with intra-articular corticosteroid.
BACKGROUND
To compare the inflammatory changes of antigen-induced temporomandibular joint (TMJ) arthritis in rabbits by different histological methods and to evaluate the immunomodulatory effect of intra-articular corticosteroid injections histologically.


METHODS
35 rabbits (10 weeks old) pre-sensibilized with ovalbumin were divided into three groups: a placebo group of five (saline), an arthritis group of 15 (ovalbumin) and a steroid-treated group of 15 (ovalbumin + corticosteroid). Additionally, a group of seven rabbits receiving no sensibilization with ovalbumin and no intra-articular injections served as controls. Histomorphometry of the inflammatory changes in the subsynovial connective tissue (SSCT) of the TMJ included: (i) semi-quantitative (S-Q) scoring of inflammation and synovial proliferation, (ii) thickness measurements and fractional surface and (iii) stereological quantitative assessment of volume and plasma cells in thick sections of the SSCT by an optical fractionator.


RESULTS
The histomorphometry showed synovial proliferation in both the arthritis and the steroid groups. The plasma cell count obtained by the optical fractionator was significantly reduced when treating the TMJ with corticosteroids. However, the thickness of the synovial lining and volume of the SSCT as well as S-Q scoring of inflammation showed no difference between the arthritis and the steroid-treated groups. The optical fractionator proved a superior tool compared to S-Q assessments.


CONCLUSIONS
Counting of plasma cells in the SSCT showed that corticosteroids reduced the inflammation, but did not eliminate it. Semiquantitative scoring of synovial proliferation and inflammation demonstrated low sensitivity regarding changes in immunomodulation in antigen-induced arthritis compared to stereological quantitative estimations using an optical fractionator.
Kristensen
Kasper Dahl
KD
Department of Orthodontics, School of Dentistry, University of Aarhus, Aarhus, Denmark. kdahl@odont.au.dk
Stoustrup
Peter
P
Küseler
Annelise
A
Pedersen
Thomas Klit
TK
Nyengaard
Jens Randel
JR
Hauge
Ellen-Margrethe
EM
Herlin
Troels
T
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D001169:Arthritis, Experimental / Q000276:immunology / Q000517:prevention & control; D001171:Arthritis, Juvenile / Q000276:immunology / Q000517:prevention & control*; D002452:Cell Count; D004195:Disease Models, Animal; D005260:Female; D017746:Joint Capsule / Q000276:immunology / Q000473:pathology; D010950:Plasma Cells / Q000166:cytology / Q000276:immunology; D011817:Rabbits; D018709:Statistics, Nonparametric; D013583:Synovial Membrane / Q000276:immunology / Q000473:pathology*; D013704:Temporomandibular Joint / Q000276:immunology / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000276:immunology / Q000517:prevention & control*; D014222:Triamcinolone Acetonide / Q000031:analogs & derivatives* / Q000627:therapeutic use
D000305:Adrenal Cortex Hormones; D000893:Anti-Inflammatory Agents; D014222:Triamcinolone Acetonide; C005900:triamcinolone hexacetonide