[A method for the in vivo measurement of the mineral content in an experimental animal]

Bone mineral content measurement is not as widely used in experimental conditions as in clinical practice because of the lack of adequate experimental methods. An in vivo measurement method of bone mineral content in the rat is here presented. Measurements were made at the proximal tibio-peroneal segment, which has a mainly trabecular structure, by means of single photon absorptiometry. The presence of the fibula, having cortical structure, has been shown not to affect the read values, which can be therefore attributed to the tibial metaphysis, having a mainly trabecular structure. Expressing mineral content values as a function of the measured bone diameter has proven useless. Limb repositioning on the instrument holding device is critical for the reproducibility of the measurement, but the latter is not affected by the repositioning method. Method reproducibility (depending on either the intrinsic instrumental error or the repositioning error) is 5-6%. This relatively low reproducibility of the suggested method does not prevent its use in the study of physiological and pathological variations of bone mineral content in rats, and of the means to influence it.