| Background: Type 1 diabetes is thought to be an autoimmune disease mainly mediated by celllar immunity. The progressive destruction of beta cells and absolute deficiency of insulin secretion is characteristic of the disease. The unblance between Th1 and Th2 cells play an important role in pathogenesis of the disease. Th1 cells and its cytokines induce destruction ofβcells ,while Th2 cells and its cytokines provided protction.Adminstration of insulin and B chain peptide(p9-23) can induce immunol tolerance ,and delay onset of diabetes,decrease incidence of diabetes in NOD mice.the protection was obtained by promoting the shift from Th1 cells to Th2 cells reponse.There are two different ways through which βcells die. One is necrosis, the other is apoptosis.Apoptosis is the main mode of death of βcells in NOD mice.Apoptosis of βcells have two peak:the first precedes starting time of insulitis.The second overlaps beginning time of clinic diabetes.Abnormol apoptosis ofβcells can lead to overexpression of autoantigens,and initiateβcells-directed autoimmune response.The infiltrating T cells and cytokines in islets accelerated apoptosis ofβcells,which cause the number ofβcells decrease and onset of clinic diabetes.Activation of FasL/Fas and TNF/TNFR1 apoptosis pathways can induce apoptosis ofβcells. Th1 cytokines,such as IL-1 and IFN-γ, can induce destruction ofβcells by upregulating expression of Fas onβcells.Therefore,it is supposed that insulin and B chain peptide(p9-23) can protectβcells by inhibiting expression of Th1 cytokines,then down-regulating expression of FasL/Fas and TNF/TNFR1 systems.In order to prove the hypothesis,we design this research.Background:1. Th1 cells and its cytokines can cause destruction of βcells,while Th2 cells and its cytokines can provide protection in pathogenesis of type 1 diabetes.Apoptosis is the main mode ofβcells death in NOD mices.FasL/Fas2. and TNF/TNFR1 apoptosis pathways participate apoptosis ofβcells.3. Th1 cytokines,such as IL-1 and IFN-γ, can induce expression of Fas on βcells,and bring about apoptosis of βcells.4. Insulin and B chain peptide(p9-23) can promote immune deviation from Th1 to Th2 response.Objective:1. To observe expression of cytokines IFN-γand IL-10mRNA ,and apoptosis factors Fas,FasL,TNF-α,TNFR1,CPP32mRNA in pancreata in NOD mices. To investigate the expression of Fas,FasL, TNF-α, TNFR1,CPP32 proteins in islet cells and infiltrating inflammatory cells. To made sure the relationship between the cytokines and apoptosis factors .2. Insulin and B chain peptide(p9-23) are administrated intraperitoneally to neonatal and 4 week-old NOD mices.,to observe their effects on incidence of diabetes,insulitis extent,and expression of IFN-γ,IL-10,Fas,FasL,TNF-α,TNFR1,CPP32mRNA in pancreata.Part oneObjective: to observe expression of IFN-γ,IL-10,Fas,FasL,TNF-αTNFR1,CPP32mRNA in pancreata,and expression of Fas,FasL,TNF-α,TNFR1,CPP32 protein in islet cells and infiltrating inflammatory cells.Method:54 female NOD mices were divided into three groups (C1,C2,C3)and each group consisted of 18 mices.The mices of C1,C2 and C3 groups were killed respectively at 4th,15th,30th week(or onset of diabetes),and picked out their pancreata.Level of IFN-γ,IL-10,Fas,FasL,TNF-α, TNFR1,CPP32mRNA in pancreata were detected by RT-PCR.Insulitis scores were observed by HE straning.Expression of Fas,FasL, TNF-α,TNFR1,CPP32 protein were measured by immunohistochemical straining in islet cells and inflammatory cells.In addition,20 female NOD mices was examined for incidence of diabetes.Urine glucose was monitored from age of 12 weeks.If urine glucose was positive,blood glucose was measured.The animals were consided diabetic when blood glucose was consistently >11.1mmol/L.Results: Incidence of the female NOD mices was 70% until 30 weeks.Beginning time of diabetes was at 17th week.Insulitis scores were from0 to 1 grade in majority of 4 week-old mices,2-3 grade in 15 week-old mices,3-4 grade in 30 week-old or di...
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