Histochemical and Morphological Characteristics of the Levator Ani Muscle in Rats

Autor(es):Mostrar menos -

do Carmo, Edna Maria ^[1] ; Miyaoka, Tatiana Midori ^[1] ; da Silva, Natalia Denipoti ^[1] ; de Camargo, Marcela Regina ^[1] ; Rodrigues Rocha, Ana Paula ^[1] ; Pelai, Eliza Bizetti ^[1] ; Jaquiel Figueira, Jessica Ibde ^[1] ; Prado Teles Fregonesi, Cristina Elena ^[1] ; Sato, Jose Takaiti ^[2] ; de Machado, Roberto Gameiro ^[3] ; de Souza, Wilson Machado ^[3]

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ, Sch Sci & Technol, Dept Phys Therapy, Presidente Prudente, SP - Brazil

^[2] Sao Paulo Western Univ, Dept Vet Med, Presidente Prudente, SP - Brazil

^[3] Sao Paulo State Univ, Sch Vet Med, Dept Biosci Prod & Anim Hlth, Aracatuba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: INTERNATIONAL JOURNAL OF MORPHOLOGY; v. 29, n. 4, p. 1195-1201, 2011.
• Citações Web of Science: 1

Resumo

The current study aimed to analyze the histochemical and morphological characteristics of the levator ani muscle in rats. For this, we used 10 Wistar rats (5 males and 5 females), weighing between 200 and 765g. The animals were dissected fresh and in formalin for the levator ani muscle anatomical observation. Muscle fragments were collected and frozen in n-Hexane previously cooled in liquid nitrogen. Then, the muscles were transferred to a microtome cryostat (HM 505 E Microm), being fixed in metal mounts with the adhesive Tissue Freezing Medium. Histological sections of 6.0µm were removed and subjected to HE staining. Other sections were subjected to NADH-TR and SDH reactions. After being dissected and fixed, the architecture of the female pelvic floor revealed the presence of two muscles: iliocaudalis and pubocaudalis. The anatomical inspection in male rats revealed, pronouncedly, the presence of the levator ani muscle: ischiocavernosus and bulbocavernous. We therefore observed a marked anatomical difference between animals of the same species, which does not occur with humans. The HE staining revealed muscular fibers with preserved morphology, contours ranging from polygonal to rounded, acidophilic cytoplasm, one or more peripheral nuclei with rounded shape and dense chromatin aspect. The fibers were organized in fascicles arranged by a dense connective tissue, the perimysium, and each fiber surrounded by the endomysium, composed of loose connective tissue. The sections subjected to NADH-TH and SDH, whose reactions show the activity of oxidative or glycolytic muscle fibers, allowed the identification of the two types of fiber. The fast-twitch fiber shows weaker reactivity, whereas the slow-twitch fiber has small diameter and intense reactivity, especially in the subsarcolemmal, presenting a highly oxidative metabolism. It was found that the pelvic floor muscles in rats are composed primarily by fast-twitch fibers, while in humans they are predominantly formed by slow-twitch fibers. Thus, models with these animals and various kinds of protocols for muscular training should be used cautiously. (AU)

• Processo FAPESP: 05/51207-8 - Características morfológicas do músculo elevador anal em ratas
• Beneficiário: Tatiana Midori Miyaoka
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica