Study On The Mucosal-associated Lymphoid Tissue Of Small Intestine And Its Ability Of Anti- Moniezia Benedeni Infection In Sheep

In order to study the morphological characteristic of mucosal-associated lymphoid tissue of small intestine of goats and its ability of anti-Moniezia benedeni infection, the method of anatomy, histology, histochemistry, histopathology, trichinoscopy and scanning electron microscope were used to observe the anatomical location and characteristic of mucosal-associated lymphoid tissue of small intestine of normal goats, also observe the microstructure of the tissue and conduct cell count (IELs, goblet cells, plasma cells and eosinophile granulocytes). At the same time, the morphological characteristic of Moniezia benedeni and the changes of the mucosal-associated lymphoid tissue was studied through the model of goats naturally infected with Moniezia benedeni. The results showed that (1) Peyer's patches were distributed in the whole small intestine of adult goats, the appearance of peyer's patches was nodular, faviform and ribbon form, the size, number and the area of peyer's patches increased subsequently, the distribution tendency of sheep peyer's patches was same as other ruminants. The histology showed that a huge number of mucosal immunity-associated cells were distributed in mucosa layer; There were two or three lines of lymphoid nodules at the substratum of mucous membrane of duodenum and jejunum, and there was only one continuous ribbon form lymphoid nodule in the distal portion of jejunum and ileum. The Microstructure characteristic of aggregate lymphoid nodule area was that there were hill-shaped dome area between the villus, M cells were distributed on the surface of dome with different number and different apperence. (2) The number of mucosal immunity-associated cells in small intestine of adult goats was counted and the data analysis showed that the number of IELs and goblet cells all increased substantially from duodenum to ileum in adult goats(P<0.05), but the number of eosinophile granulocytes (EOS) decreased substantially from duodenum to ileum(P>0.05),the number of plasma cells increased from duodenum to jejunum and decreased from jejunum to ileum(P<0.05). (3) The research first reported the microstructure of Moniezia benedeni, SEM shows that the scolex was ellipsoid, and there was compact microvilli on the surface of its body, the role of microvilli was absorption of nutrients. (4) Necropsy found that Moniezia benedeni was mainly distributed on the surface of jejunum with abundant aggregate lymphoid nodules, small intestine was thickened where worm was parasite, the mucosal surface was covered with white mucus, and there were also some punctuate hemorrhage on it, also there were congestion, necrosis and some other pathological changes. Comparision of the contract group and the control group, we found that the mucosal epithelium was desquamated in the contract group, epithelial cells, IELs and goblet cells proliferated in the integrated mucosa. There was hyperemia in capillaries of lamina propria, and was hemorrhage in somewhere, and hyperplasia of diffuse lymphoid tissue and goblet cells of intestinal gland happened in different degree. Aggregate lymphoid nodules were hyperplasia in the submucoa of small intestine, interfollicular area disappeared, some hyperplasia form the new dome area. SEM shows that there were abundant mucus covered on the surface of intestinal villus in the contract group. Some villus were desquamated, there were some crater form dome area between the intestinal villus, the epithelium of dome was desquamated in some dome area, and the number of dome area in the contract was more than the control group. (5)The number of mucosal immunity-associated cells in small intestine of adult goats was counted and the data analysis was performed using the one-way ANOVA, the results showed that IELs, goblet cells, plasma cells and eosinophile granulocytes in small intestine of contract group was more than the control group.The results suggested that the mucosal-associated lymphoid tissue of small intestine of adult goats which comprised by the aggregate lymphoid nodules and mucosal immunity-associated cells through a complementary way was a strong mucosal immune barrier, it maybe has a relationship with the different environment. The cellular immunity function of the goat infected with Moniezia benedeni was increased through the proliferation of IELs, lymphocytes and M cells, and the humoral immunity function was also increased through the proliferation of plasma cells, also through the proliferation of non-special mucosal immunity-associated cells(EOS and goblet cells) enhanced the anti-infection ability, at the same time, the adult goats can strengthen the resistence of the infection of Moniezia benedeni by the proliferation of lymphoid tissues, it is thus clear that goat could strength the local immune function by the proliferation of relative lymphoid tissues and cells to monitor the immune escape of parasite, and to resist the infection of Moniezia benedeni. Parasite infection and the anti-infection mechanism of body is complex, and needs further study.