Effects of Ovariectomy on Rat Genioglossal Muscle Contractile Properties and Fiber-Type Distribution

Liu, Yuehua; Jia, Shanshan; Hou, Yu-xia

doi:10.2319/031608-149.1

Cited by 19 publications

(13 citation statements)

References 24 publications

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“…Although some studies report that estrogen replacement therapy does not influence muscle strength in postmenopausal women (30, 31), an increasing number of scholars believe that estrogen is an important protective factor in skeletal muscles (32–35). The results of this study are consistent with the results of our previous studies carried out under normoxic conditions (36, 37), which supported the protective effects of estrogen on rat genioglossus muscle, but focused on the improvement in muscle fatigue resistance. As the loss of HIF‐1α had the potential to maintain muscle fatigue resistance, a diminished concentration would thus be protective for the stabilization of airway patency.…”

Section: Discussionsupporting

confidence: 92%

Down‐regulation of hypoxia inducible factor‐1α: a possible explanation for the protective effects of estrogen on genioglossus fatigue resistance

Jia

Liu

2010

European J Oral Sciences

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Patients with obstructive sleep apnea/hypopnea syndrome (OSAHS) often exhibit fatigued or inefficient upper airway dilator muscle activity. It has been shown that estrogen may have some impact on upper airway contractility under normoxic conditions. Chronic intermittent hypoxia (CIH) is a frequent feature of OSAHS, and it may alter muscle susceptibility to oxidative stress, a characteristic of a fatigable nature. Hypoxia inducible factor-1 (HIF-1) is a transcription factor that is responsible for the regulation of oxygen homeostasis under hypoxic conditions. We examined the effects of estrogen on the contractility of the genioglossus by exposing rats to alternating cycles of 6-8% O(2) every 15 s for a total duration of 35 d. The results showed that muscle fatigue resistance was significantly decreased after CIH but was partially reversed after estrogen treatment. Compared with the control group, real-time reverse transcription-polymerase chain reaction and western blotting showed higher levels of HIF-1alpha messenger RNA and protein in the CIH group, but estrogen treatment reduced, in a dose-independent manner, the levels of HIF-1alpha messenger RNA and protein in rats exposed to CIH. We conclude that CIH induced the expression of HIF-1alpha in the genioglossus and altered the physical properties towards a more fatigable phenotype, whereas estrogen inhibited the over-expression of HIF-1alpha, and this may account for the improvement of upper airway muscle endurance in CIH rats.

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Section: Discussionsupporting

confidence: 92%

Down‐regulation of hypoxia inducible factor‐1α: a possible explanation for the protective effects of estrogen on genioglossus fatigue resistance

Jia

Liu

2010

European J Oral Sciences

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“…Consequently, regulation of MHC subtypes seems to be dependent on the hormone levels of E 2 , which also impacts cellular performance of MDSCs. Estrogen is known to promote proliferation and differentiation of MDSCs that express functional ERs [18] and plays an important role in regulating muscular function [19]. Raising evidence is given that sex-related differences in MDSC performance are a factor for the heterogenity in cell-induced skeletal muscle regeneration, as investigations revealed that female MDCSs display an advanced marker expression profile, whereas male MDSCs show a higher differentation potential upon subject to oxidative stress [20].…”

Section: Discussionmentioning

confidence: 99%

Estradiol Modulates the Expression Pattern of Myosin Heavy Chain Subtypes via an ERα-Mediated Pathway in Muscle-Derived Tissues and Satellite Cells

Guo

Liu

Konermann

et al. 2014

Cell Physiol Biochem

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Background: Muscle-derived satellite cells (MDSCs) express MHC molecules intimately related to muscle function, which is supposed to be affected by local estrogen (E₂) levels. However, cellular targets and molecular mechanisms involved are poorly understood. Methods: Genioglossus (GG) muscle tissues and MDSCs were derived from SHAM, ovariectomized or ovariectomized and 17 β-estradiol injected rats (n=10 ⁄ group). ERα, ERβ, MHC expression and underlying regulatory mechanisms were investigated by RT-PCR, western blot and immunohistochemistry, inter alia upon selective antagonist exposure and Si-RNA transfection. MDSC viability and cell cycle were examined by MTT and flow cytometry. Results: E₂ upregulated MHC-I and downregulated MHC-IIb expression in MDSCs. E₂ mediated effects on these molecules were inhibited by ERα-selective antagonist MPP and si-ERα, whereas they persisted upon exposure to ERβ-selective antagonist PHTPP. ERα was significantly higher expressed in muscle tissues compared to ERβ. ER positive stainings were fewer in the ovariectomized than in the SHAM group. Injection of E₂ only increased the positive staining of ERα, but not of ERβ. Conclusion: Results suggest that E₂ regulates MHC expression mainly through an ERα-mediated pathway with opposing effects on MHC-I and MHC-IIb. Thus, different hormonal processes that impact muscular pathophysiology presumably govern the functional properties of these molecules.

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“…Mitochondrial function and the response to oxidative stress can be strongly affected by fiber composition (Anderson & Neufer 2006, Picard et al 2008, 2012. Ovariectomy has been reported to modify muscle contractile properties, phenotype, metabolism, and force-generating capacity (Moran et al 2006, Liu et al 2009c, whereas estradiol replacement reverses these alterations (Moran et al 2007, Liu et al 2009b, Cavalcanti-de-Albuquerque et al 2014. In this sense, it is not possible to rule out the hypothesis that the changes observed in white gastrocnemius mitochondrial function and oxidative stress response from OVX and OVXCE 2 rats are mediated by a change in fiber metabolism or phenotype; further studies would be necessary.…”

Section: Discussionmentioning

confidence: 99%

Estradiol stimulates mitochondrial biogenesis and adiponectin expression in skeletal muscle

Capllonch-Amer¹,

Sbert-Roig²,

Galmés-Pascual³

et al. 2014

Journal of Endocrinology

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Sexual dimorphism has been found in mitochondrial features of skeletal muscle, with female rats showing greater mitochondrial mass and function compared with males. Adiponectin is an insulin-sensitizing adipokine whose expression has been related to mitochondrial function and that is also expressed in skeletal muscle, where it exerts local metabolic effects. The aim of this research was to elucidate the role of sex hormones in modulation of mitochondrial function, as well as its relationship with adiponectin production in rat skeletal muscle. An in vivo study with ovariectomized Wistar rats receiving or not receiving 17b-estradiol (E 2 ) (10 mg/kg per 48 h for 4 weeks) was carried out, in parallel with an assay of cultured myotubes (L6E9) treated with E 2 (10 nM), progesterone (Pg; 1 mM), or testosterone (1 mM). E 2 upregulated the markers of mitochondrial biogenesis and dynamics, and also of mitochondrial function in skeletal muscle and L6E9. Although in vivo E 2 supplementation only partially restored the decreased adiponectin expression levels induced by ovariectomy, these were enhanced by E 2 and Pg treatment in cultured myotubes, whereas testosterone showed no effects. Adiponectin receptor 1 expression was increased by E 2 treatment, both in vivo and in vitro, but testosterone decreased it. In conclusion, our results are in agreement with the sexual dimorphism previously reported in skeletal muscle mitochondrial function and indicate E 2 to be its main effector, as it enhances mitochondrial function and diminishes oxidative stress. Moreover, our data support the idea of the existence of a link between mitochondrial function and adiponectin expression in skeletal muscle, which could be modulated by sex hormones.

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Effects of Ovariectomy on Rat Genioglossal Muscle Contractile Properties and Fiber-Type Distribution

Abstract: 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.

Cited by 19 publications

References 24 publications

Down‐regulation of hypoxia inducible factor‐1α: a possible explanation for the protective effects of estrogen on genioglossus fatigue resistance

Down‐regulation of hypoxia inducible factor‐1α: a possible explanation for the protective effects of estrogen on genioglossus fatigue resistance

Estradiol Modulates the Expression Pattern of Myosin Heavy Chain Subtypes via an ERα-Mediated Pathway in Muscle-Derived Tissues and Satellite Cells

Estradiol stimulates mitochondrial biogenesis and adiponectin expression in skeletal muscle

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