OSTEOARTHRITIS IN CYNOMOLGUS MACAQUES - A PRIMATE MODEL OF NATURALLY-OCCURRING DISEASE

The objective of the present study was to determine if naturally occur ring osteoarthritis of the knee joints that is similar to the conditio n in humans develops in cynomolgus macaques. Knee joints from 58 young adult (mean age, 7.4 years) female cynomolgus macaques were studied w ith x-ray densitometry, high-detail radiography, and histology. The an imals studied were subjects in a triad designed to examine the effects of the administration of sex steroids on atherosclerosis; except for a control group, the monkeys had been either ovariectomized or treated with sex steroids for 2 years. Therefore, the data were analyzed to d etermine if these treatments, both of which can influence bone density , affected the severity of osteoarthritis. There was a high prevalence of osteoarthritic lesions, morphologically similar to those seen in h umans. Bone changes were more common and severe than cartilage changes and morphologically appeared to precede the cartilage changes. Treatm ent with testosterone resulted in increased body weight, body mass ind ex, and bone mineral content in the femur and tibia but did not affect the severity of osteoarthritis. These data indicate that naturally oc curring osteoarthritis developed in the knee joints of cynomolgus maca ques; these animals may be a useful model for the study of osteoarthri tis in humans.