Bioimpedance spectroscopy for the estimation of body fluid volumes in mice.
Conventional indicator dilution techniques for measuring body fluid volume are laborious, expensive, and highly invasive. Bioimpedance spectroscopy (BIS) may be a useful alternative due to being rapid, minimally invasive, and allowing repeated measurements. BIS has not been reported in mice; hence we examined how well BIS estimates body fluid volume in mice. Using C57/Bl6 mice, the BIS system demonstrated <5% intermouse variation in total body water (TBW) and extracellular (ECFV) and intracellular fluid volume (ICFV) between animals of similar body weight. TBW, ECFV, and ICFV differed between heavier male and lighter female mice; however, the ratio of TBW, ECFV, and ICFV to body weight did not differ between mice and corresponded closely to values in the literature. Furthermore, repeat measurements over 1 wk demonstrated <5% intramouse variation. Default resistance coefficients used by the BIS system, defined for rats, produced body composition values for TBW that exceeded body weight in mice. Therefore, body composition was measured in mice using a range of resistance coefficients. Resistance values at 10% of those defined for rats provided TBW, ECFV, and ICFV ratios to body weight that were similar to those obtained by conventional isotope dilution. Further evaluation of the sensitivity of the BIS system was determined by its ability to detect volume changes after saline infusion; saline provided the predicted changes in compartmental fluid volumes. In summary, BIS is a noninvasive and accurate method for the estimation of body composition in mice. The ability to perform serial measurements will be a useful tool for future studies.
Chapman
M E
ME
Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
Hu
L
L
Plato
C F
CF
Kohan
D E
DE
D000818:Animals; D001823:Body Composition; D001826:Body Fluids / Q000378:metabolism*; D001835:Body Weight; D017666:Deuterium Oxide; D017097:Electric Impedance; D045604:Extracellular Fluid / Q000378:metabolism; D005260:Female; D007424:Intracellular Fluid / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011865:Radioisotope Dilution Technique; D015203:Reproducibility of Results; D013462:Sulfur Radioisotopes
D013462:Sulfur Radioisotopes; D017666:Deuterium Oxide
Ann Pharmacother. 2001 Jan;35(1):123-4
11197573
J Appl Physiol (1985). 1991 May;70(5):2039-44
1864785
Nat Med. 2005 Aug;11(8):861-6
16007095
Int J Body Compos Res. 2009 Jan 1;7(1):21-26
19668348
J Am Coll Nutr. 1992 Apr;11(2):199-209
1578098
Proc Natl Acad Sci U S A. 2005 Jun 28;102(26):9406-11
15956187
J Clin Eng. 1992 Nov-Dec;17(6):505-10
10124463
Lab Anim. 1998 Jan;32(1):65-71
9481696
Lancet. 2009 Oct 24;374(9699):1423-31
19748665
Am J Physiol Renal Physiol. 2008 Dec;295(6):F1635-40
18784261
Am J Vet Res. 1992 Feb;53(2):251-7
1575394
Am J Physiol. 1977 Jan;232(1):R60-5
319689
Phys Med Biol. 1993 Mar;38(3):337-46
8451277
Am J Physiol Renal Physiol. 2005 Oct;289(4):F692-8
15928212
Appl Radiat Isot. 1998 May-Jun;49(5-6):447-55
9569513
Pediatr Res. 1984 Apr;18(4):392-3
6718099