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Effects of ovariectomy on rat genioglossal muscle contractile properties and fiber-type distribution.
Angle Orthod. 2009 May; 79(3):509-14.AO

Abstract

OBJECTIVE

To test the hypothesis that ovariectomy has no effects on contractile, histochemical, or biochemical properties of the rat genioglossus (GG).

MATERIALS AND METHODS

Eight-week-old female Sprague-Dawley rats were randomly assigned into three groups: normal group (Normal), sham-operated group (Sham), and ovariectomized group (OVX). Four weeks later, genioglossal electromyography activity (EMGgg) and contractile properties were measured, including relative integrated EMG (iEMG), maximal twitch tension, 70%-decay time, and fatigue index (FI). Then rats were sacrificed and paired GG were removed for further analysis. Adenosine-triphosphatase (ATPase) staining was performed to determine the percent fiber-type distribution and to identify cross-sectional area (CSA) of muscle fibers. Myosin heavy chain (MHC) phenotypes were determined by gel electrophoresis.

RESULTS

Ovariectomy reduced EMG activity and contractile properties of the GG. Following ovariectomy, the CSA of type IIA and the proportion of MHCIIA decreased significantly. The MHC isoform composition of GG transferred from relative slow-twitch to fast-twitch isoform, following the order MHCIIB --> MHCIIX --> MHCIIA. Sham operation had no effect on any of the parameters.

CONCLUSIONS

The hypothesis is rejected. The contractile properties of the GG are sensitive to ovariectomy. These changes were, at least in part, associated with changes in the amount and type of contractile protein expressed.

Authors+Show Affiliations

Department of Orthodontics, School of Stomatology, Tongji University of China, 399 Yanchang Zhong Road, Shanghai 200072, China. joshua66@126.comNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19413380

Citation

Liu, Yue-Hua, et al. "Effects of Ovariectomy On Rat Genioglossal Muscle Contractile Properties and Fiber-type Distribution." The Angle Orthodontist, vol. 79, no. 3, 2009, pp. 509-14.
Liu YH, Jia SS, Hou YX. Effects of ovariectomy on rat genioglossal muscle contractile properties and fiber-type distribution. Angle Orthod. 2009;79(3):509-14.
Liu, Y. H., Jia, S. S., & Hou, Y. X. (2009). Effects of ovariectomy on rat genioglossal muscle contractile properties and fiber-type distribution. The Angle Orthodontist, 79(3), 509-14. https://doi.org/10.2319/031608-149.1
Liu YH, Jia SS, Hou YX. Effects of Ovariectomy On Rat Genioglossal Muscle Contractile Properties and Fiber-type Distribution. Angle Orthod. 2009;79(3):509-14. PubMed PMID: 19413380.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of ovariectomy on rat genioglossal muscle contractile properties and fiber-type distribution. AU - Liu,Yue-Hua, AU - Jia,Shan-Shan, AU - Hou,Yu-Xia, PY - 2008/03/01/received PY - 2008/07/01/accepted PY - 2009/5/6/entrez PY - 2009/5/6/pubmed PY - 2009/9/16/medline SP - 509 EP - 14 JF - The Angle orthodontist JO - Angle Orthod VL - 79 IS - 3 N2 - OBJECTIVE: To test the hypothesis that ovariectomy has no effects on contractile, histochemical, or biochemical properties of the rat genioglossus (GG). MATERIALS AND METHODS: Eight-week-old female Sprague-Dawley rats were randomly assigned into three groups: normal group (Normal), sham-operated group (Sham), and ovariectomized group (OVX). Four weeks later, genioglossal electromyography activity (EMGgg) and contractile properties were measured, including relative integrated EMG (iEMG), maximal twitch tension, 70%-decay time, and fatigue index (FI). Then rats were sacrificed and paired GG were removed for further analysis. Adenosine-triphosphatase (ATPase) staining was performed to determine the percent fiber-type distribution and to identify cross-sectional area (CSA) of muscle fibers. Myosin heavy chain (MHC) phenotypes were determined by gel electrophoresis. RESULTS: Ovariectomy reduced EMG activity and contractile properties of the GG. Following ovariectomy, the CSA of type IIA and the proportion of MHCIIA decreased significantly. The MHC isoform composition of GG transferred from relative slow-twitch to fast-twitch isoform, following the order MHCIIB --> MHCIIX --> MHCIIA. Sham operation had no effect on any of the parameters. CONCLUSIONS: The hypothesis is rejected. The contractile properties of the GG are sensitive to ovariectomy. These changes were, at least in part, associated with changes in the amount and type of contractile protein expressed. SN - 0003-3219 UR - https://www.unboundmedicine.com/medline/citation/19413380/Effects_of_ovariectomy_on_rat_genioglossal_muscle_contractile_properties_and_fiber_type_distribution_ L2 - https://meridian.allenpress.com/angle-orthodontist/article-lookup/doi/10.2319/031608-149.1 DB - PRIME DP - Unbound Medicine ER -