The Immunomorphology Characteristic Of Small Intestine Mucous Membrane In Yak And Its Anti-infection Ability On Moniezia

Peyer's patches are mainly distributed in the ileum and appendix of animals andhumans, it was the induced position of mucosal immune response. The structure,distribution, size and appearance of Peyer's patches are different in different species. Themacroanatomy, histology, histochemistry, and microscopic measurements were used tostudy on the immunomorphology characteristic of small intestine mucous membrane ofyak and its relationship with age,20yaks of the following four age groups were studied:young (0.5,1and1.5years old); pubertal (2,2.5and3years old); middle-aged (4,5and6years old), and old (8,9and10years old). The exact number and size of the Peyer'spatches were recorded and measured, and the appearance of Peyer's patches in eachsegment of small intestine was observed, and the number of mucosalimmunity-associated cells in small intestine of yaks in different age group were countedand recorded. The results showed:(1) There were two distinct types of Peyer's patches:nodular, which was distributed in the oncoides portion of duodenum; faviform, whichwas mainly distributed in the jejunum and ileum; The appearance of Peyer's patches injejunum and ileum was long strip appearance, the length of it was between0.4cm to17cm, and the width of it was between0.2cm to3.7cm. Statistical analysis indicated thatthe number of Peyer's patches was altered with age. The number peaked in middle-agedyaks, and declined subsequently with age. No age-related macroscopic variations in theshape or size of the Peyer's patches were found. Peyer's patches were still present with acomparable macroscopic and histological structure in yaks of10years of age.(2) Thehistology results indicated that the development of Peyer's patches was altered with age,it was the most developed during the pubertal period. Microscopic measurement resultshowed that the depth of Peyer's patches in mid-portion of ileum was903.20μm, theaggregate lymphatic nodule was two to three lines at the substratum of mucousmembrane, the number of dome area was the most during the pubertal period. Thenumber of lymphoid tissue at the substratum of mucous membrane of small intestine ofadult and old yaks was less than the puberty yaks. When at the old period the lymphoidtissue decreased obviously and the depth of Peyer's patches at the substratum of mucousmembrane of small intestine was also decreased.(3) Cell counting results found that thedistribution tendency of those mucosal immune cells in small intestine was that: thenumber of intraepithelial lymphocytes, goblet cells and mast cells was gradually reducedfrom duodenum to ileum, whereas the number of eosinophils and plasma cells wasgradually increased from duodenum to ileum. The results also indicated that the numberof mucosal immunity-associated cells were altered with age. The number peaked in pubertal and middle-aged yaks, and declined subsequently with age (P<0.05). The resultsindicated that puberty yaks have stronger immunological function.Moniezia is a large tapeworm inhabiting the small intestines of ruminants such assheep, goats and cattle. At the same time, Moniezia is the most destructive internalparasites responsible for the increased mortality and decreased animal production as theycould cause many pathological changes which may lead to severe illness or death of thehost. Unlike sheep, cattle and other ruminates, Moniezia expansa has weak pathogenicityto the adult yak, most of yak have no clinical symptoms after infected with Monieziaexpansa. We speculate that the weak pathogenicity of Moniezia expansa to adult yakmaybe due to the reaction of mucosal immunity-associated cells in digestive tract of theyak. In this paper the histology, histochemistry and cell counting methods were used toevaluate the effects of Moniezia expansa on the number of mucosal immune cells(intraepithelial lymphocytes, eosinophils, goblet cells, plasma cells and mast cells) insmall intestine of adult yaks, and M cells were also observed by scanning electronmicroscope. The results showed:(1) The number of intraepithelial lymphocytes wereincreased in the infected group, compared with the normal group, and the difference wasstatistically significant (P<0.01), the number of eosinophils, goblet cells, plasma cellsand mast cells were all increased in the infected group, compared with the normal group,and the difference was statistically significant (P<0.01).(2) The distribution tendency ofthose cells in small intestine was that: the number of intraepithelial lymphocytes, gobletcells and mast cells was gradually reduced from duodenum to ileum in two groups,whereas the number of eosinophils and plasma cells was gradually increased fromduodenum to ileum, and the number of those mucosal immune cells in defferent segmentof small intestine was different, the difference was statistically significant(P<0.05),except the plasma cells in jejunum and ileum.(3) The results of scanning electronmicroscope showed that the intestinal villus were broken or desquamated partly, thenumber of dome area was more than that in the control group, M cell was also more thanthat in the control group. The results indicated that Moniezia expansa has intenseinfluence on the number of mucosal immune cells in small intestine of adult yaks, thehyperplasia of those cells can strengthen the anti-infections ability of adult yaks. It isshowed that the anti-infection ability of the intestinal mucous membrane of adult yak isstrong, so the parasites have a weak pathopoiesis on it.