Changes in bone mineral density and bone-specific alkaline phosphatase in ovariectomized ewes

Area of Science:

• Veterinary Medicine
• Endocrinology
• Bone Biology

Background:

• Developing an adequate animal model for human osteoporosis is crucial for testing new therapeutic agents.
• The aged ewe presents a potential model due to observed bone remodeling changes within three months and bone mass differences six months post-ovariectomy.

Purpose of the Study:

• To evaluate longitudinal changes in bone mass and bone-specific alkaline phosphatase (BSAP) over six months in ovariectomized (OVX) ewes.
• To assess the suitability of the aged ewe as an animal model for human osteoporosis.

Main Methods:

• Thirty 7-9 year old ewes were divided into sham-treated, OVX, and OVX with estrogen implants (OVXE) groups.
• Bone mineral density (BMD) was measured at the vertebrae, calcaneus, and distal radius using dual-energy X-ray absorptiometry (DEXA) at baseline, 3, and 6 months.
• Bone-Specific Alkaline Phosphatase (BSAP) was measured monthly.

Main Results:

• Vertebral BMD (L4-L6/L5-L7) was significantly lower in the OVX group compared to the sham group (p < 0.08) after six months.
• No significant changes in BMD were observed in the calcaneus or distal radius.
• Ovariectomy was confirmed by increased luteinizing hormone, and estrogen implants increased uterine weight.

Conclusions:

• The ovariectomized ewe model demonstrates a significant decrease in vertebral bone mineral density, indicating its potential for studying osteoporosis.
• This model may be suitable for evaluating therapeutic agents aimed at treating postmenopausal osteoporosis.
• Further research is warranted to fully validate this model for preclinical osteoporosis studies.