title: Hypothyroidism modifies morphometry and thyroid-hormone receptor expression in periurethral muscles of female rabbits.
abstract: To evaluate the morphometry and thyroid-hormone receptor (TR) expression in pelvic (pubococcygeus, Pcm) and perineal (bulbospongiosus, Bsm) muscles of control and hypothyroid female rabbits.
  
  
  
  Hypothyroidism was induced administering 0.02% methimazole in the drinking water for one month. Hematoxylin-eosin stained muscle sections were used to evaluate the fiber cross-sectional area (CSA) and the number of peripheral myonuclei per fiber. Immunohistochemistry was used to calculate the proportion of TR immunoreactive nuclei per fiber. Significant differences were considered at a P ≤ 0.05.
  
  
  
  As compared to control rabbits, hypothyroidism increased the averaged fiber CSA and the myonuclei per fiber in the Bsm. Although the myonuclei number per fiber was also increased in the Pcm, the effect concerning the fiber CSA was only observed in a fraction of the Pcm fibers. Both TRα and TRβ were similarly expressed in the Pcm and Bsm. Hypothyroidism increased the expression of the TRα in the Bsm. Meanwhile, the expression of TR isoforms in the Pcm was not altered.
  
  
  
  Our findings support that the TR signaling is directly involved in morphometrical changes induced by hypothyroidism in the Pcm and Bsm. The effect of hypothyroidism on the Pcm and Bsm could be related to the different type of fiber and metabolism that these muscles have. Neurourol. Urodynam. 35:895-901, 2016. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México.|Doctorado en Neuroetología, Universidad Veracruzana, Xalapa, México.
authors.forename: Octavio
authors.initials: O
authors.lastname: Sánchez-García
authors.affiliation: Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México.|Doctorado en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, Tlaxcala, México.
authors.forename: Julia
authors.initials: J
authors.lastname: Rodríguez-Castelán
authors.affiliation: Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México.|Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México-DF, México.
authors.forename: Margarita
authors.initials: M
authors.lastname: Martínez-Gómez
authors.affiliation: Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México.
authors.forename: Estela
authors.initials: E
authors.lastname: Cuevas
authors.affiliation: Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México. fcocastelan@uatx.mx.
authors.forename: Francisco
authors.initials: F
authors.lastname: Castelán
mesh_terms: D019412:Anatomy, Cross-Sectional; D000818:Animals; D013956:Antithyroid Agents; D002682:Chinchilla; D005260:Female; D007037:Hypothyroidism / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*; D007150:Immunohistochemistry; D008713:Methimazole; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology*; D017773:Pelvic Floor / Q000473:pathology; D011817:Rabbits; D011988:Receptors, Thyroid Hormone / Q000096:biosynthesis*; D037021:Thyroid Hormone Receptors alpha / Q000378:metabolism; D037042:Thyroid Hormone Receptors beta / Q000378:metabolism; D014521:Urethra / Q000378:metabolism* / Q000473:pathology*
chemical_list: D013956:Antithyroid Agents; D011988:Receptors, Thyroid Hormone; D037021:Thyroid Hormone Receptors alpha; D037042:Thyroid Hormone Receptors beta; D008713:Methimazole
keywords: pelvic floor; perineum; skeletal muscle; thyroid hormones