Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 1999
Publication Date: March 15, 2000
Citation: Lukaski, H.C., Marchello, M.J., Hall, C.B., Siders, W.A. 2000. Validity of dual x-ray absorptiometry (DXA) to assess body composition of rats exposed to various stressors [abstract]. The Federation of American Societies for Experimental Biology Journal. 14:A486. Technical Abstract: Although use of DXA for routine assessment of human body composition is common, validation of this method is lacking. This study examined the validity of DXA (Hologic QDR 2000W; Bedford, MA) relative to chemical analyses (CA) to determine soft-tissue composition of rats with altered energy and fluid status. Male, weanling Sprague-Dawley rats were fed the basal, AIN-76 growth diet and were randomly assigned to groups: control (CN), obese (OB; basal diet modified to contain 30% fat), and furosemide (DH; 10 mg/kg ip 2 hr before DXA). Treatments affected (p<0.001) weight and fat mass (FM). Group n Weight, g <p>Fat mass, g Fat-free mass, g DXA CA Delta DXA CA Delta DXA CA Delta CN 12 348 350 -2**ab 44 42 2 303 308 -5 OB 7 373 374 -1**a 70 66 4 303 309 -6 DH 7 351 355 -4**b 48 44 4 303 311 -8 Although DXA underestimated (p<0.001) body weight, it discriminated body composition by treatment. DXA underestimated weight the least in OB, which was similar to CN, but more (p<0.001) than in DH. DXA gave estimates of soft-tissue composition that were similar (p>0.05) to CA and distinguished differences in FM by treatment; fat-free mass was similar in all groups. Except for the DH group (1.1%), the relative errors in body weight were 0.2 to 0.6%. Relative errors in DXA determination of FM (8%) are less than previously reported (20-30%). Similarly, the error of DXA determination of FFM was 1.6-2.6% which also is less than reported (6%) by others. These findings indicate the validity of DXA to measure soft tissue composition small animals exposed to nutritional perturbations.