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Effects of 14 days of microgravity on fast hindlimb and diaphragm muscles of the rat.
Eur J Appl Physiol. 2009 Aug; 106(6):885-92.EJ

Abstract

The purpose of the present study was to determine the effects of 14 days of microgravity on specific rat fast-twitch muscles, and to compare these data with previous data from rat fast-twitch muscles exposed to microgravity for 10 days (Kraemer et al. 2000). Hindlimb muscles containing predominately fast fibers [extensor digitorum longus (EDL), superficial "white" (GSW) and deep "red" (GDR) gastrocnemius] and the diaphragm (DIA) were removed from flight and ground-based control animals and analyzed for: muscle mass, fiber type distribution, cross-sectional area, and myosin heavy chain (MHC) isoform content. Gravitational unloading for 14 days caused significant decreases in muscle mass (8-9%) and cross-sectional area of almost all fiber types (10-35%) from both EDL and gastrocnemius muscles. However, microgravity had little effect on fiber type composition in these muscles with significant changes occurring only in the EDL type IID fiber population (9.5% decrease). Similarly, relative MHC isoform content was only slightly altered by exposure to microgravity (increased content of MHCIIa in flight EDL). No changes in area, fiber type percentages, or MHC isoform content were detected in the DIA following the 14-day spaceflight. Similar to data gathered following a 10-day spaceflight (Kraemer et al. 2000), the 14-day flight did not appear to cause significant slow-to-fast (I --> IIA) or fast-to-faster (IIA --> IID --> IIB) transformations in hindlimb muscles containing predominantly fast-twitch fibers. However, the longer period of gravitational unloading did result in additional loss in muscle fiber cross-sectional area with involvement of more major fiber types.

Authors+Show Affiliations

Department of Anatomy, College of Osteopathic Medicine, University of New England, 431 Stella Maris, Biddeford, NE 04005, USA. mschuenke@une.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

19484473

Citation

Schuenke, Mark D., et al. "Effects of 14 Days of Microgravity On Fast Hindlimb and Diaphragm Muscles of the Rat." European Journal of Applied Physiology, vol. 106, no. 6, 2009, pp. 885-92.
Schuenke MD, Reed DW, Kraemer WJ, et al. Effects of 14 days of microgravity on fast hindlimb and diaphragm muscles of the rat. Eur J Appl Physiol. 2009;106(6):885-92.
Schuenke, M. D., Reed, D. W., Kraemer, W. J., Staron, R. S., Volek, J. S., Hymer, W. C., Gordon, S., & Perry Koziris, L. (2009). Effects of 14 days of microgravity on fast hindlimb and diaphragm muscles of the rat. European Journal of Applied Physiology, 106(6), 885-92. https://doi.org/10.1007/s00421-009-1091-9
Schuenke MD, et al. Effects of 14 Days of Microgravity On Fast Hindlimb and Diaphragm Muscles of the Rat. Eur J Appl Physiol. 2009;106(6):885-92. PubMed PMID: 19484473.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of 14 days of microgravity on fast hindlimb and diaphragm muscles of the rat. AU - Schuenke,Mark D, AU - Reed,David W, AU - Kraemer,William J, AU - Staron,Robert S, AU - Volek,Jeff S, AU - Hymer,Wesley C, AU - Gordon,Scott, AU - Perry Koziris,L, Y1 - 2009/05/31/ PY - 2009/05/12/accepted PY - 2009/6/2/entrez PY - 2009/6/2/pubmed PY - 2009/10/15/medline SP - 885 EP - 92 JF - European journal of applied physiology JO - Eur J Appl Physiol VL - 106 IS - 6 N2 - The purpose of the present study was to determine the effects of 14 days of microgravity on specific rat fast-twitch muscles, and to compare these data with previous data from rat fast-twitch muscles exposed to microgravity for 10 days (Kraemer et al. 2000). Hindlimb muscles containing predominately fast fibers [extensor digitorum longus (EDL), superficial "white" (GSW) and deep "red" (GDR) gastrocnemius] and the diaphragm (DIA) were removed from flight and ground-based control animals and analyzed for: muscle mass, fiber type distribution, cross-sectional area, and myosin heavy chain (MHC) isoform content. Gravitational unloading for 14 days caused significant decreases in muscle mass (8-9%) and cross-sectional area of almost all fiber types (10-35%) from both EDL and gastrocnemius muscles. However, microgravity had little effect on fiber type composition in these muscles with significant changes occurring only in the EDL type IID fiber population (9.5% decrease). Similarly, relative MHC isoform content was only slightly altered by exposure to microgravity (increased content of MHCIIa in flight EDL). No changes in area, fiber type percentages, or MHC isoform content were detected in the DIA following the 14-day spaceflight. Similar to data gathered following a 10-day spaceflight (Kraemer et al. 2000), the 14-day flight did not appear to cause significant slow-to-fast (I --> IIA) or fast-to-faster (IIA --> IID --> IIB) transformations in hindlimb muscles containing predominantly fast-twitch fibers. However, the longer period of gravitational unloading did result in additional loss in muscle fiber cross-sectional area with involvement of more major fiber types. SN - 1439-6327 UR - https://www.unboundmedicine.com/medline/citation/19484473/Effects_of_14_days_of_microgravity_on_fast_hindlimb_and_diaphragm_muscles_of_the_rat_ L2 - https://dx.doi.org/10.1007/s00421-009-1091-9 DB - PRIME DP - Unbound Medicine ER -