2003, Number 4
Acta Ortop Mex 2003; 17 (4)
Measurement of the bone mineral content in lumbar vertebrae L2-L4 of female Long Evans rats by means of dual energy X-ray and chemical analysis
Quintana-Armenta A, Ruiz-Rosano L, Valdez-Mijares R, Diez-García MP et al
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ABSTRACTA non-invasive method for determining bone mass of rats is by dual energy X-ray absorptiometry (DXA). Using a Hologic QDR-2000 densitometer programmed and calibrated for the study of rat L2-L4 lumbar vertebrae, we assessed the precision and accuracy of bone mineral density (BMD) and bone mineral content (BMC) measurements of a group of 14 female Long Evans rats of 22 weeks of age and 290-320 g of body weight. Under anesthesia, three consecutive determinations with repositioning were made per rat. BMD and BMC were (mean ± SD): 175.20 ± 2.00 mg/cm2 and 450.60 ± 18.00 mg, respectively, with group intra-assay coefficients of variation of 1.15 ± 0.20% and 4.12± 1.95% (mean ± SD), respectively, showing good precision. The spectrophotometric analysis of the content of calcium, magnesium, and phosphorous in the product of HNO3 digestion of the L2-L4 vertebrae of the same rats were (in mg, mean ± SD): 131.21 ± 6.93, 2.22 ± 0.17 and 55.77 ± 3.45, respectively, with linear correlation coefficients (r) vs their BMC of 0.52, 0.33 and 0.47 (p > 0.05) (measure of accuracy), which suggest that BMC measurements are approximate, and do not substitute for chemical analyses.