title: Differential damage and repair responses of pubococcygeus and bulbospongiosus muscles in multiparous rabbits.
abstract: OBJECTIVE
  To determine the extent of damage and regeneration associated with multiparity on the pubococcygeus and bulbospongiosus muscles.
  
  
  METHODS
  Age-matched virgin nulliparous and multiparous rabbits that were killed at days 3 and 20 after the fourth delivery were used to harvest pubococcygeus and bulbospongiosus muscles. The activity of the lysosomal enzyme β-glucuronidase was used as a muscle damage indicator. The number of immunoreactive myofiber-associated nuclei anti-Pax7, -MyoD, and -myogenin, as well as the anti-desmin immunoreactive area were measured in muscle sections to estimate some regenerative stages. Significant differences were considered at a P ≤ 0.05.
  
  
  RESULTS
  The β-glucuronidase activity was increased at postpartum day 20 in the pubococcygeus muscle. This variable was unaltered in the bulbospongiosus muscles of multiparas regardless of the postpartum day on which this was measured. The number of immunoreactive nuclei anti-Pax7 in the pubococcygeus muscle was similar between nulliparas and multiparas, whilst those of anti-MyoD and anti-myogenin were increased at postpartum days 3 and 20. The same was true for these latter three markers evaluated in the bulbospongiosus muscles, supporting an ongoing regeneration. The desmin-positive percentage of muscle area per field was increased at postpartum day 20 in the pubococcygeus muscle, whilst such an increment was seen at postpartum days 3 and 20 in the bulbospongiosus muscles.
  
  
  CONCLUSIONS
  Damage and regeneration of the pubococcygeus and bulbospongiosus muscles are differently influenced by multiparity in rabbits. This could rely on the anatomical location, metabolism, myofiber composition, and muscle exertion during pregnancy and/or the delivery of each muscle.
authors.affiliation: Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México.|Doctorado en Neuroetología, Universidad Veracruzana, Xalapa, México.
authors.forename: Kenia
authors.initials: K
authors.lastname: López-García
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.|Doctorado en Neuroetología, Universidad Veracruzana, Xalapa, México.
authors.forename: Octavio
authors.initials: O
authors.lastname: Sánchez-García
authors.affiliation: Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México-DF, México.|Instituto de Neuroetología, Universidad Veracruzana, Xalapa, México.
authors.forename: Pablo
authors.initials: P
authors.lastname: Pacheco
authors.affiliation: Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México.|Departamento de Biología Celular y Fisiología, 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: Francisco
authors.initials: F
authors.lastname: Castelán
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D005966:Glucuronidase / Q000378:metabolism; D018482:Muscle, Skeletal / Q000201:enzymology / Q000293:injuries / Q000473:pathology / Q000503:physiopathology*; D017570:MyoD Protein / Q000378:metabolism; D018008:Myogenin / Q000378:metabolism; D051763:PAX7 Transcription Factor / Q000378:metabolism; D010298:Parity; D017773:Pelvic Floor / Q000293:injuries / Q000473:pathology / Q000503:physiopathology*; D011247:Pregnancy; D011817:Rabbits; D012038:Regeneration; D014947:Wounds and Injuries / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*
chemical_list: D015415:Biomarkers; D017570:MyoD Protein; D018008:Myogenin; D051763:PAX7 Transcription Factor; D005966:Glucuronidase
keywords: pelvic floor; perineum; satellite cells; skeletal muscle