The ferret as a small animal model with BMU-based remodeling for skeletal research

The need exists for a small animal model with bone metabolic unit (BMU)-based remodeling to mimic the bone loss found in postmenopausal women. The purpose of this investigation was to evaluate the ferret as a potential model for skeletal research. Specifically, we determined whether the ferret: 1) exhibits evidence of BMU-remodeling, 2) has a skeletal response to parathyroid hormone (PTH) similar to other remodeling species, and 3) loses bone in response to reduced estrogen levels.

Using three sets of experiments, we determined the response of female ferrets to ovariectomy/light cycle manipulation or to administration of PTH. Scanning electron microscopy, light microscopy, determination of estrogen levels and/or single-photon absorptiometry (SPA) were used for evaluation.

The ferret was found to exhibit BMU-based remodeling, and may therefore provide a small animal remodeling species for skeletal research. Ferrets reach skeletal maturity between four and seven months of age as evidenced by closure of the growth plate and maturation of trabecluae from thin rods to thick rods and plates. PTH treatment resulted in a marked increase in bone mass accompanied by the PTH-induced tunneling phenomenon known to occur in dogs and humans but not rats. The response to PTH supports the use of the ferret in studies of bone anabolic agents. Bone mass in the proximal tibia was significantly reduced when estrogen depletion was induced by either bilateral ovariectomy or short light/dark cycles (8 hour light, 16 hour dark). Maintenance of intact ferrets under short-light conditions mimiced ovariectomy in terms of serum estrogen levels, uterine weights, and tibial BMD.(ABSTRACT TRUNCATED AT 250 WORDS)