Immunohistochemical Evaluation of the Muscularis Mucosae in the Ruminant Forestomach

Abstract

The muscularis mucosae and condensed fibrous layer of the ruminant forestomach were studied by immunohistochemistry using specific antibodies against alpha-smooth muscle actin (alphaSMA) and gamma-smooth muscle actin (gammaSMA). The specimens were collected from the rumen, reticulum and omasum of cattle, water buffalo, sheep, goat, Barbary sheep, Japanese serow, sika deer and mouse deer. The muscularis mucosae showed immunoreactivity for both alphaSMA and gammaSMA. On the other hand, the condensed fibrous layer appearing between the propria mucosa and tela submucosa was immunoreactive only for alphaSMA except for that in the goat and Barbary sheep reticulum which is intermingled with gammaSMA immunoreactivity. The distribution of muscularis mucosae and/or condensed fibrous layer varied among the compartments of forestomach and ruminant species. In the rumen, only the condensed fibrous layer was detected. On the other hand, the omasum contained only the muscularis mucosae. In the reticulum, both were detected. The amount of the condensed fibrous layer in the reticulum varied among different species in the following order of abundance: goat > Barbary sheep > sika deer> sheep > water buffalo > cattle and Japanese serow. Smooth muscle cells of external muscle layer were immunoreactive for alphaSMA and gammaSMA whereas those of blood vessels and pericytes were immunoreactive only for alphaSMA. The present findings on the actin immunoreactivity and distribution profile of muscularis mucosae and the condensed fibrous layer provide additional knowledge to further understand the histophysiological specialization of the different compartments of the ruminant forestomach.

Morphometric and immunohistochemical study of the reticulum of red deer during prenatal development

“…In ruminants, the appearance was placed in perinatal stages in buffalo (Panchamukhi & Siravastava, 1980); and in sheep, at approximately 75% of gestation (Franco et al. 1993c) or during postnatal development (Wardrop, 1961; Kitamura et al. 2003).…”

Morphometric and immunohistochemical study of the omasum of red deer during prenatal development

“…In cattle, Totzauer & Sinowatz (1990) placed it at 120 days (43% of gestation). In the perinatal stages, Kitamura et al. (2003) detected muscularis mucosae in omasal smaller laminae in goat, sheep, cow and buffalo (in decreasing order of abundance of muscular fibres).…”

Severe Hypoplasia of the Omasal Laminae in a Japanese Black Steer with Chronic Bloat-A Case Report

“…Motility of the omasal canal is coordinated with that of the reticulorumen, while omasal body contractions occur independently and slower than reticuloruminal contractions [2]. The muscularis mucosae and intermediate muscle sheet in the omasal laminae may contribute to its independent movement from the external wall [1,4]. The function of the omasum is not completely understood.…”

“…The omasal laminae are muscular sheets comprising 2 lateral layers and an intermediate smooth muscle layer, covered with non-glandular stratified squamous epithelium [4,20]. Forestomach movements are essential for fermentation and are effective through the following steps: (1) mechanical maceration of the ingesta and its inoculation with rumen micro-organisms, (2) mixing saliva with the rumen contents to buffer VFAs, (3) prevention of local accumulation of VFAs, (4) assisting VFA removal by the rumen wall, and (5) elimination of fermentation gases [6].…”