| Background : Cryptosporidium species are important oppotunistic protozoans, which can cause cryptosporidiosis in vertebrate, including human and domestic animals . Cryptosporidium species distribute world- wide , infection can develop severe complications. There are 2 kinds of Cryptosporidium in this group which can cause human infection: Crypto- sporidium parvum (C.parvum) and Cryptosporidium hominis (C.hominis). C.hominis affects humans only, while C.parvum spreads many species of mammals including human.Many researches indicate that Cryptosporidium infection is closely related to hosts'immunity, including cellular and humoral immunity . The former, especially CD4+T cell and IFN-γare very important in controlling Cryptosporidium infection and eliminating inflammatory reaction. It suggests that we can control infections though killing the parasites and improve the immunity of the hosts.Over the last 20 years, there are many report achievements about cryptosporidiosis, such as pathogenisis, molecular biology, integrate control-immunology, but a few are about the infection immunity and drug therapy. So far, there is no effective chemotherapeutic agents and appro- aches.Objective: To observe the immunological regulation of Fructus Psoraleae, dihydroartemisinin and the combination of them on the changes of the intestine mucosa, the ultrastructure of intestinal epithelial cells, MHC-II expression on antigen-presenting cells(including macrophage, dendritic cell and so on) in the lamina propria of ileum and the secretion of IL-12p70 in serum when mouse infected with Cryptosporidium parvum(C. parvum). To explore the role of traditional Chinese medicine in regulating hosts'immunity of APC and killing Cryptosporidium. Meanwhile, this research can provide new prevention and cure method against cryptosp- oridiosis.Materials and methods: 60 mice were were randomly divided into five groups: mice threated with dihydroartemisinin(group C), Fructus Psoraleae(group D) and the combination of them(group E). Another two groups were used as positive control(group B) and normal mouse(group A) resp respectively. According treating time, each of the groups was randomly subdivided into 2 groups as : A1,B1,C1,D1,E1(1 week treatment ); A2,B2,C2,D2,E2(2 week treatment ). 48 mice in group B,C,D,E were injected subcutaneously with dexamethasone. When the mice were infected with C. parvum, they were threated with the medicine respectively. The intestine tissue was observed via HE and the ultrastructure of intestinal epithelial cells was observed by transmission electron microscopy. We observed the expression of MHC-II by Immunohistochemistry, the secretion of IL-12p70 in serum by ELISA .Values were expressed as x±s and the difference significance between mean values was analyzed by one-way analysis of variance (ANOVA) followed by the Duncan test for multiple comparison which uses Statistical Package for Social Sciences 10.0 (SPSS 10.0) computer package. The P values smaller than 0.05 were selected to indicate statistical significance between groups.Results: (1) The damaged intestine got improved and repaired, and a significant decrease of the amount of C. parvum oocysts in feces was shown in the treated groups (C,D,E)compared with positive control group (B) (P<0.05). (2) In 1 week treatment groups, the MHC-II expression of group C1 was higher than that of normal group A1 and combination treating group E1(P<0.05); In 2 week treatment groups, there were no difference between the expression in groups C2,D2,E2 and that in group A2, but the expression in groups C2,D2,E2 was higher than that in group B2(P<0.05). (3) In 1 week treatment groups, the IL-12p70 level in group C1 and D1 were higher than that in A1,B1,E1 (P<0.01),the level in group C1 was higher than that in D1 (P<0.01) ;In 2 week treatment groups, the level in group C2 and D2 were higher than that in A2,B2,E2 (P<0.01),the level in group C2 was higher than that of D2 (P<0.01).Conclusions:1. Traditional Chinese medicine Fructus Psoraleae, dihydroartemisinin and the combination of them are effective to regulate the function of APC in Mouse Cryptosporidiosis. The increased MHC-II expression and IL-12p70 secretion may be important factors. Mice immunity can be improved, and then it can kill Cryptosporidium parvum.2. In the three groups, the function of dihydroartemisinin is the most effective in regulating the function of APC. The IL-12p70 level is higher than that of any others. It is used to treat mice cryptosporidiosis effectively in this experiment.3. During C. parvum infected intestinal epithelial cell, the parasite can inhibit and damage the immune function of APC, and reduce the expression of MHC-II and reduce the IL-12p70 level in serum.It further suggests that C. parvum inhibiting the immunologic process of the host immune response to C. parvum infection, and then the parasite can infecte the intestinal epithelial cells. |
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