TNO Preventie en Gezondheid National Institute of Public Health and Environmental Protection (RIVM), Laboratory of Pathology, Netherlands
|Source:||Journal of Bone and Mineral Metabolism, 1 Supplement, 12, S61-67|
Health · ageing rat models for osteopenia · histomorphometry · postmenopausal osteopenia · senile osteopenia · vitamin D deficiency
Ageing rats are more appropriate for studies on age-related osteopenia than growing or young adult rats, because of the better similarity with ageing man. Both have a negative bone balance, a low bone turnover, decreasing intestinal calcium absorption and decreasing levels of systemic hormones influencing the calcium and bone metabolism. According to the purpose of the study, different models can be used, as for example ageing and recently or long ago ovariectomized rats showing respectively high or low bone turnover with concomitant negative bone balance (model for postmenopausal osteopenia), aged rats showing low bone turnover (model for senile osteopenia), ageing rats with shortage or deficiency of vitamin D at normocalcaemia (model for age related osteopenia with concomitant vitamin D deficiency) or at hypocalcaemia (model for age related osteopenia with concomitant vitamin D deficiency at renal insufficiency). In intact ageing female rats, monitoring of the cyclic pattern is important, as irregularly occurring estrous cycles during an experimental study can influence the results considerably. Moreover, account should be taken of the age related diseases which can influence the number of ageing rats to be used (unpredictability of spontaneous deaths) and the strain of rats (age related diseases) to be used. Because of the naturally occurring decrease in osteoprogenetor calls and the retarded maturation of preosteoblasts into osteoblasts, the aged rat model for senile osteopenia seems especially suited for studies on drugs influencing these osteoblast precursors. Intermittent PTH treatment appears to be effective in all rat models for osteopenia. For the inconsistency of the results in the aged rat model for senile osteopenia, some explanations are suggested. © 1994 Japanese Society of Bone Metabolism Research.