STATIC AND DYNAMIC HISTOMORPHOMETRIC DATA IN 9-YEAR-OLD TO 11-YEAR-OLD EWES

The technique of trans-iliac biopsy and subsequent histomorphometrical examination in ewes is reported. Biopsies were obtained from 18 clini cally normal ewes, aged 9 to 11 years which had been given tetracyclin e intramuscularly twice, 11 days apart, at a dose rate of 20 mg/kg. Th ere were no complications associated with the administration of the te tracycline at this dose and at this site. The core of the biopsy consi sted of cancellous bone between two cortices allowing complete histomo rphometric analysis from undecalcified sections. Two clearly distinct and separate labels were visible under ultraviolet light with the labe lling method used. Primary, surface, volume and dynamic data were meas ured or calculated and are reported. Certain static and dynamic histom orphometric variables from this study were compared to those of other workers who used aged (but slightly younger) ewes, and there were many similarities between the studies. A comparison was also made of absol ute values of bone volume (BV/TV%), relative osteoid volume (OV/BV%) a nd mineral apposition rate (MAR, mcm/day) of this study, and those of men and pre- and postmenopausal women reported in recently published d ata, as well as parameters of 14 elderly normal women measured by one of us. It was concluded that iliac crest biopsy in the ewe is a safe e ffective method to quantitate skeletal changes and our data compares f avorably with other workers in this species. Furthermore, the BV/TV%, OV/BV% and MAR; of ewes of this age resembled that of both men and pos tmenopausal women at least in their 6th or 7th decade of life. Therefo re 9- to 11-year-old ewes may be a useful models for studies and thera peutic trials of both osteopenia and osteoporosis of the skeleton.