Sexual dimorphism in the osteoarthritis of STR/ort mice may be linked to articular cytokines.
BACKGROUND
STR/ort mice spontaneously develop degenerative changes of the knee joints resembling human osteoarthritis (OA), with the males being more severely affected than the females.


OBJECTIVE
To analyse the early changes leading to OA by examining the articular cytokine expression and degenerative changes in STR/ort mice.


METHODS
122 STR/ort mice of both sexes aged between 2 and 15.5 months were included. Thin sections of the knees were analysed for osteoarthritic changes by haematoxylin/eosin staining. The articular cytokine expression was investigated by immunohistochemical staining using monoclonal antibodies specific for interleukin (IL)6, tumour necrosis factor alpha, transforming growth factor beta1 (TGFbeta1), IL1beta, IL4, and IL10, respectively.


RESULTS
Both cartilage degeneration and articular cytokine expression differ between the sexes. The protection from cartilage degeneration in the female mice correlates with an increased expression of TGFbeta1 and IL4 at 2 months of age.


CONCLUSIONS
The increased expression of TGFbeta1 and IL4 in young STR/ort female mice suggests that the sexual dimorphism is mediated through the articular expression of cytokines involved in cartilage metabolism.
Mahr
S
S
Deutsches RheumaForschungs-Zentrum, Berlin, Germany.
Menard
J
J
Krenn
V
V
Müller
B
B
D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism; D019902:Chondrocytes / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D020370:Osteoarthritis, Knee / Q000378:metabolism*; D012727:Sex Characteristics