Mucin profiles of the abomasum in bulls and rams: A comparative study

Abstract

Many pathogens require direct binding to mucosal cells to cause an infection. The mucosal epithelium of the digestive tract, which is covered by a mucin layer, fulfills several protective functions that are essential to maintaining the health of the digestive tract. Mucins are glycoproteins, which are found on membranes and in mucus gels and protect the underlying mucosal cells. Both membrane-associated mucins and secreted mucins are critical components of mucosal defense. The aim of this study was to determine the localization and expression of mucin profile of the abomasum via histochemistry and immunohistochemistry. The abomasums of 20 bulls and 20 rams were evaluated. Histochemical examination showed that neutral and acidic mucins were present in the mucosa and the glands of the pars cardiaca, fundus, and pars pylorica of the abomasums of both bulls and rams. However, the expression of acidic mucins was weak in the superficial glands and strong in the deep glands of the abomasum of rams. In both bulls and rams, MUC1, MUC5AC, and MUC6 were expressed in the glandular epithelial cells in all regions of the abomasum. Interestingly, while MUC2 was not expressed in the pars cardiaca and fundus, it was weakly expressed in the parietal cells of the pars pylorica in both species. In conclusion, the presence of neutral and acidic mucins and MUC1, MUC2, MUC5AC, and MUC6 proteins in luminal epithelial and glandular cells of abomasum in the bulls and rams support the hypothesis that mucins play a key role in the protection of the abomasal mucosa against infectious agents.

Prenatal development and histochemical characteristics of gastrointestinal mucins in sheep fetuses

“…We have studied the histochemical staining pattern of the epithelial mucins in sheep fetuses at various gestational ages, to determine their developmental changes and the localizations in the gastrointestinal tract. To our knowledge, althoughmucin types found in the gastrointestinal tract have been described in several mammals (Filipe, ; Forman, ; Karakoç et al, ; Kotzé & Coetzee, ; Krause, ; Schumacher et al, ; Sheahan & Jervis, ), up to now, the presence and distribution of mucins in the gastrointestinal tract of sheep fetuses has not been investigated. Furthermore, we checked whether the different MUCs (MUC1, MUC2, MUC5AC, and MUC6) were expressed in sheep fetal abomasums, small intestine and colon using conventional primary antibodies.…”

“…The gastrointestinal mucosal epithelium has various functions in sustaining the health of the digestive system. A mucus layer composed of ions, water, lipids, proteins, and glycoproteins covers the mucosal epithelium and provides protection against both mechanical, chemical and enzymatic damage and pathogenic microorganisms (Karakoç et al, ; Rose & Voynow, ). Gastric mucins are secreted by the luminal epithelial cells and gastric glands in some animal species and humans (Lacunza, Bara, Segal‐Eiras, & Croce, , b; Liman, Alan, and Küçük Bayram, ; Terada, ; Vernygorodskyi, ).…”

“…Gastric mucins are secreted by the luminal epithelial cells and gastric glands in some animal species and humans (Lacunza, Bara, Segal‐Eiras, & Croce, , b; Liman, Alan, and Küçük Bayram, ; Terada, ; Vernygorodskyi, ). In humans and the opossum, superficial cells of the gastric mucosa and glandula pylorica secrete only neutral mucins, while in the vole, rat, bison, rabbit, Japanese macaque, Rhesus monkey, raccoon dog, white‐tailed deer, guinea pig, and cat, they produce both acidic and neutral mucins (Karakoç et al, ; Schumacher et al, ). Ganesh, Subramani, and Halagowder () reported that in humans, while the gastric mucosa secretes a low level of sialomucins, neutral mucins are localized to the mucosal glands and foveolar epithelial cells in the antrum, the latter of which also contain sulfomucins.…”

“…Ganesh, Subramani, and Halagowder () reported that in humans, while the gastric mucosa secretes a low level of sialomucins, neutral mucins are localized to the mucosal glands and foveolar epithelial cells in the antrum, the latter of which also contain sulfomucins. Karakoç et al () demonstrated that, in rams and bulls, the abomasum contains acidic (sulfated and carboxylated) and neutral mucins, as well as glycogen. However, these researchers also reported that the two species differ for mucin localization in the abomasum.…”

“…Mucin distribution in different part of the gastrointestinal tract varies with anatomical region, cell type, pathology, and species (Scillitani, Zizza, Liquori, & Ferri, ). Types of mucin found in the gastrointestinal tract have been histochemically described in several mammals (Filipe, ; Forman, ; Karakoç, Sağsöz, & Ketani, ; Kotzé & Coetzee, ; Krause, ; Schumacher, Duku, Katoh, Jörns, & Krause, ; Sheahan & Jervis, ). Information available on the prenatal distribution of mucins in the mammalian gastrointestinal tract is scarce (Beyaz & Liman, ; de la Hoz, Eyheramendy, Felipe, & Díaz, ; Felipe, Callejas, & Cabodevila, ; Tano de la Hoz, Flamini, & Díaz, ).…”