The influence of long-term treadmill exercise on bone mass and articular cartilage in ovariectomized rats.
BACKGROUND
Loss of bone quality and deterioration of articular cartilage are commonly seen after menopause. While exercise may protect against tissue degeneration, a clear link has yet to be established. The aim of the present study is to investigate the influence of long-term treadmill exercise on changes in bone mass and articular cartilage in ovariectomized rats.


METHODS
Sixty female Sprague-Dawley rats were randomly assigned to 4 groups: ovariectomized (OVX), ovariectomized plus treadmill exercise (OVX-RUN), treadmill exercise alone (RUN), and control (CON) groups. After 36 weeks, the following variables were compared among the 4 groups. Bone mass was evaluated by trabecular bone volume and bone mineral density (BMD). Articular cartilage in the knee joints was evaluated by histology analysis and a modified Mankin score.


RESULTS
Rats in the ovariectomized groups (OVX and OVX-RUN) had significantly lower BMD and bone mass than the non-ovariectomized rats (CON and RUN), indicating that exercise did little to preserve bone mass. However, the sedentary OVX group had a significantly worse modified Mankin score (7.7 +/- 1.4) than the OVX-RUN group (4.8 +/- 1.0), whose scores did not differ significantly from the other 2 non-operated groups. The articular cartilage in the sedentary OVX rats was relatively thinner, hypocellular, and had more clefts than in the other 3 groups.


CONCLUSIONS
This study suggests that long-term exercise protects articular cartilage in OVX rats but does not retard the loss of bone mass seen in after menopause.
Chang
Ting-Kuo
TK
Institute of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan.
Huang
Chang-Hung
CH
Huang
Chun-Hsiung
CH
Chen
Hsuan-Chiang
HC
Cheng
Cheng-Kung
CK
D000818:Animals; D015519:Bone Density / Q000502:physiology*; D002358:Cartilage, Articular / Q000166:cytology / Q000502:physiology*; D004195:Disease Models, Animal; D005080:Exercise Test / Q000379:methods*; D005081:Exercise Therapy / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000166:cytology / Q000502:physiology; D020370:Osteoarthritis, Knee / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D015663:Osteoporosis, Postmenopausal / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D010052:Ovariectomy / Q000009:adverse effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D016896:Treatment Outcome