title: Differentiation of the intracellular structure of slow- versus fast-twitch muscle fibers through evaluation of the dielectric properties of tissue.
abstract: Slow-twitch (type 1) skeletal muscle fibers have markedly greater mitochondrial content than fast-twitch (type 2) fibers. Accordingly, we sought to determine whether the dielectric properties of these two fiber types differed, consistent with their distinct intracellular morphologies. The longitudinal and transverse dielectric spectrum of the ex vivo rat soleus (a predominantly type 1 muscle) and the superficial layers of rat gastrocnemius (predominantly type 2) (n = 15) were measured in the 1 kHz-10 MHz frequency range and modeled to a resistivity Cole-Cole function. Major differences were especially apparent in the dielectric spectrum in the 1 to 10 MHz range. Specifically, the gastrocnemius demonstrated a well-defined, higher center frequency than the soleus muscle, whereas the soleus muscle showed a greater difference in the modeled zero and infinite resistivities than the gastrocnemius. These findings are consistent with the fact that soleus tissue has larger and more numerous mitochondria than gastrocnemius. Evaluation of tissue at high frequency could provide a novel approach for assessing intracellular structure in health and disease.
authors.affiliation: Department of Neurology, Division of Neuromuscular Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215-5491, USA.
authors.forename: B
authors.initials: B
authors.lastname: Sanchez
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: R
authors.initials: R
authors.lastname: Bragos
authors.forename: S B
authors.initials: SB
authors.lastname: Rutkove
mesh_terms: D000818:Animals; D002138:Calibration; D058266:Dielectric Spectroscopy; D042541:Intracellular Space; D008297:Male; D053142:Mitochondrial Size; D018656:Muscle Fibers, Fast-Twitch / Q000166:cytology*; D018657:Muscle Fibers, Slow-Twitch / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar
references.citation: Muscle Nerve. 2009 Jan;39(1):16-24
references.pmid: 19058193
references.citation: Amyotroph Lateral Scler. 2012 Sep;13(5):439-45
references.pmid: 22670883
references.citation: Ann Med. 2013 Feb;45(1):4-16
references.pmid: 21867371
references.citation: Phys Med Biol. 1982 Apr;27(4):501-13
references.pmid: 7089048
references.citation: J Musculoskelet Neuronal Interact. 2013 Mar;13(1):37-44
references.pmid: 23445913
references.citation: Histochemistry. 1982;76(4):547-55
references.pmid: 7166513
references.citation: Circ Res. 1956 Nov;4(6):664-70
references.pmid: 13365072
references.citation: Med Eng Phys. 2013 Jul;35(7):949-57
references.pmid: 23058287
references.citation: IEEE Trans Biomed Eng. 2011 Dec;58(12):3376-85
references.pmid: 21878408
references.citation: Phys Med Biol. 2009 Aug 21;54(16):4863-78
references.pmid: 19636081
references.citation: Physiol Meas. 1998 May;19(2):235-45
references.pmid: 9626688
references.citation: Phys Med Biol. 1987 Aug;32(8):933-70
references.pmid: 3306721
references.citation: IEEE Trans Biomed Eng. 1984 Dec;31(12):872-8
references.pmid: 6396212
references.citation: Physiol Meas. 2006 Oct;27(10):953-9
references.pmid: 16951455
references.citation: Muscle Nerve. 2002 Mar;25(3):390-7
references.pmid: 11870716
references.citation: Phys Med Biol. 1996 Nov;41(11):2251-69
references.pmid: 8938025
references.citation: Physiol Meas. 2009 Dec;30(12):1415-27
references.pmid: 19887721
references.citation: Am J Anat. 1984 Nov;171(3):259-72
references.pmid: 6517030
references.citation: Med Eng Phys. 2013 Sep;35(9):1349-57
references.pmid: 23601379
references.citation: Physiol Meas. 2013 Mar;34(3):339-57
references.pmid: 23442821
references.citation: Muscle Nerve. 2010 Dec;42(6):915-21
references.pmid: 21104866
references.citation: Neurology. 2007 Jan 9;68(2):99-109
references.pmid: 17151339
references.citation: Neurology. 2005 Aug 9;65(3):451-2
references.pmid: 16087913
references.citation: Chest. 1994 Jun;105(6):1679-82
references.pmid: 8205860
references.citation: Circulation. 1993 Jan;87(1):199-207
references.pmid: 8419008
references.citation: Tohoku J Exp Med. 1969 Nov;99(3):225-45
references.pmid: 4188684
references.citation: Muscle Nerve. 2009 Dec;40(6):936-46
references.pmid: 19768754
references.citation: Med Biol Eng. 1967 May;5(3):271-93
references.pmid: 6068939
references.citation: Physiol Meas. 2013 Oct;34(10):1217-38
references.pmid: 24021716
references.citation: J Appl Physiol. 1972 Sep;33(3):312-9
references.pmid: 4403464
references.citation: Physiol Meas. 1999 Nov;20(4):R1-10
references.pmid: 10593226
references.citation: Anat Rec. 1988 Dec;222(4):333-9
references.pmid: 3228204
references.citation: Clin Neurophysiol. 2011 Dec;122(12):2505-11
references.pmid: 21612980
references.citation: J Appl Physiol. 1976 Feb;40(2):149-54
references.pmid: 129449
references.citation: J Clin Invest. 1987 Aug;80(2):415-24
references.pmid: 3301899