The Changes And Significance Of Dendritic Cells In The Experimental Terminal Ileitis

Objective:To investigate the changes and significance of Dendritic cells(dendritic cells, DC) in the experimental terminal ileitis.Methods:One hundred and twenty male SD rats were randomly divided into Z(model group),F(suture group)and D(control group), each group of 40 rats. The above three groups were given different experiments.Group Z were given ileum-caecum side-to-side intestinal anatomists to forma the reverse flow model. Group F were sutured in terminal ileum,to make the damage similar to group Z. Group D were given Celiac anesthesia. Randomly selected 20 SD rats were taked off the neck to death after 2 and 8 weeks, and took terminal ileum tissue to macroscopic observation and inflammatory score.The remaining specimens were undergone HE to observe the pathological changes and inflammation grading, immunohistochemical detection of CD1 a,CD83 expression and analysis, under the TEM to observe the morphological characteristics of DC.Results: 1. Terminal ileum tissue macroscopic view and microscopic observation:After 2 weeks, there were acute inflammation reponses in Group Z and group F, mucosal hyperemia and edema, mucous membrane layer visible neutrophil infiltration, two groups of inflammation score were higher than group D(P<0.05); After 8 weeks, group Z were a typical chronic inflammation change, inflammation involving the mucous and submucosa, Intestinal wall thickening, fluffy structure was not clear, gland to reduce or disappear, hyperplasia of lymphoid follicle, infiltrating lymphocytes and plasma cells.And group F and group D appeared no significant inflammation, group Z build higher inflammation score to group F and group D(P < 0.05).2. The morphology of DC was observed under TEM: Group D showed some DC, small cell volume and near-circular, shortage of protuberant, low cytoplasmic density, few organelles, lots of bubbles, the nucleus shape was irregular, concave visible surface, light chromatin, visible nucleoli, conforms to the immature DC morphological characteristics;When group Z in 2 weeks and 8 weeks, the number of DC increased obviously, larger cell volume and irregular shape, cell surface branch-like protrusions, a lot of organelles, few bubbles, nucleus' shape was diversity and nucleus located in the side of the cell, legible nuclear membrane, nucleus heterochromatin enlargement, conform to the mature DC morphological characteristics.3.Level of CD1 a in terminal ileum: Immunohistochemical staining showed three groups of SD rats in the terminal ileum tissue CD1 a in the mucosa and submucosa were positive expression.After two weeks, The difference of three groups' CD1 a positive cells infiltrating density had statistically significant(P<0.05), group Z was the highest;After 8 weeks,the expressed level of CD1 a was highest in group Z,there was statistically significant difference to group F and group D(P<0.05), but no statistically significant between group F and group D(P> 0.05). Group Z at 2 and 8 week, inflammation score 1-4group, 4-8group, 8-13 group in the three groups of mucous membrane CD1 a positive cells infiltrating density were compared, the difference had statistical significance(P<0.05), with highest 8-13 group, CD1 a expression level and degree of inflammation were positively correlated.4. Level of CD83 in terminal ileum: Immunohistochemical staining display group Z and group F of SD rat CD83 positive expression, turned brownish yellow, mainly in the mucosa and submucosa, group D was weak expressed. After 2 weeks, the positive cells of CD83 in group Z and group F were significantly increased, The above two groups' CD83 positive cells infiltrating density than group D, the difference had statistical significance(P<0.01), group Z was highest; After 8 weeks,CD83 positive cells infiltrating density of group Z was highest, the difference was statistically significant to group F and group D,(P<0.05), but no statistically significant difference between group F and group D(P>0.05). Group Z at 2 and 8 week, inflammation score 1-4group,4-8group,8-13 group of three groups of mucous membrane of CD83 positive cells infiltrating density were compared, the difference had statistical significance(P<0.05), but higher than group D, CD83 expression level and degree of inflammation were positively correlated..Conclusions: 1. The morphology and structural of DC have changed from immature to mature in the ETI pattern,may be associated with antigen uptake and presenting features. 2. CD1a+DC, CD83+DC in the mucosa of ETI significantly increased, and the degree of inflammation are positively correlated. 3. The morphology, structure and function of DC have changed, it prompte DC participate in the formation of ETI and may be relate to activation of the intestinal immune system.