| Objective: Chronic lymphocytic thyroiditis (Hashimoto`s-disease, HT) is one of the organ-specific autoimmune diseases. The hyperfunction of type 1 help T cell (Th1) plays a key role in the generation and development of HT. 1,25-dihydroxy vitsmin D3 (1,25(OH)2D3) is the active form of Vitamin D3,which can inhibit the activity of Th1 cell and its cytokin through many links.This experiment plans to establish the animal model of human HT—experimental autoimmune thyroidits(EAT) of Wistar rat,and to interfere with 1,25(OH)2D3 on different phases of EAT,and to observe the effects of 1,25(OH)2D3 in rat EAT,which can provid theoretical evidences for its clinical application to HT.Methods:1. To establish the EAT rat model: The Clean-grade female Wistar rats aged 6-8 weeks were randomly divided into model group and normal group. The EAT model established by subcutaneous injecting Thyroglobulin from porcine thyroid gland(pTg)+Freund adjuvant (FA) 100ug into rats per week starting from 0th week until the 8th week. Meanwhile, the model group rats were given 0.05% KI water to drink.The normal group rats were only given FA for subcutaneous injected and normal water. The model groups rats were drawn blood every 2 week, which would be examined the levels of the TGAb and TMAb by radioimmunoassay (RIA). Collecting blood and thyroid gland after executed all rats.The tissues of rat thyroid gland were histologically examined by HE stain. The levels of serum IFN-γ, IL-4, IL-10 and IL-12 were measured by the enzyme linked immunosorbent assay (ELISA).2. The interference of 1, 25(OH)2D3 on EAT rat: The Wistar rats were randomly divided into : the group A rats were treated 1,25-(OH)2D3 from 0~6th week with intragastric administration(A1) and intraperitoneal injection(A2), the group B rats immune sensitizatized after 2 weeks were treated 1, 25(OH)2D3 from 2~8th week with intragastric administration (B1) and intraperitoneal injection (B2). The rats of the positive controll groups (group C) and the negative control groups (group D) received the treatment peatnut oil. All rast are executed until pTG- immune sensitized 6th .week or 8th weeks. To observe the thyreoid pathologic morphous by HE stain.. The level of the TGAb and TMAb by RIA; And to evaluate the levels of serum IFN-γ, IL-4, IL-10 and IL-12 by ELISA.Results:1. EAT model establishment: compared with the rats of normal control groups, the thyreoid pathologic morphous of EAT rats appears thyroid gland inflammatary pathological changes. Compared with 0 week, the level of TGAb and TMAb of the EAT rat starts from the 2th to 8th week rised, appearing a significantly increase tendency (P<0.05). The level changes of 2-8 weeks are not noticeable statistical disparity (P>0.05).The level of IFN-γand IL-12 of EAT model group rat is remarkably higher than the normal control (P<0.05); And Comparing with the normal control, the the level of IL-4, IL-10 of EAT rat are signifisant reduced (P<0.01);2. The interference of 1, 25(OH) 2D3 on EAT rat on two phase⑴The effects of 1, 25(OH)2D3 to group A, compared with the group C1, the thyroid gland structure of group A rats maintain integrity, and the levels of TGAb and TMAb are appearly decrease (P<0.05). And there are not statistical difference between A and D1 groups.The levels of serum IFN-γand IL-12 are appearly lower than group C (P<0.05), the levels of serum IL-4 and IL-10 are remarkably increase (P<0.001), and all of these cytokines are not statistical difference between group A and negative group D2 (P>0.05). There are not significant difference between A1 and A2 groups about the histological morphous, levels of antibody and cytokines.⑵The effects of 1, 25 (OH)2D3 to group B: compared with the group C2, most of the thyroid gland and follices structure of group B maintained integrity. The levels of TG/TMAb decreased significently, but they are higher than the group D2 (P<0.05). The levels of IFN-γand IL-12 are lower than group C2 (P<0.05), the levels of IL-4 and IL-10 are remarkably increase.And all of these cytokines are not statistical difference between groupB and group D2 (P>0.05). Meanwhile, there are not significant difference between B1 and B2 groups about the histological morphous, levels of antibodies and cytokines.Conclusion: 1. The EAT rat estabishment by using of Wistar rat successly imitatedthe pathological process of human HT. The method of giving PTg+FA +KI to rat as immune sensitization was confirmed convenient and reliablitale.2. The EAT rats characterised Th1 cells enhanced, which is corresponding with the human` HT.3. The rats that given 1, 25(OH)2D3 before the estabishing the EAT mode have lower incidence: Compared with the positive group ,the thyroid gland structure maintains integrity, and the levels of antibodies and cytokines were parallel with the normal extent.4. The rats that given 1, 25(OH)2D3 after EAT occured have been improved on disease: the inflammation of EAT released, and the levels of IFN-γ, IL-12 decreased ,the levels of IL-4, IL-10 rised.5. According to the histological morphous and levels of serum antibodies and cytokines, there was no difference between intragastric administration groups and intraperitoneal injection groups.
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