The Immune Mechanisms Of Rolipram On Type 1 Diabetes In NOD Mice

[Objective] To study the immune mechanisms of rolipram on type 1 diabetes in non-obese diabetic mice by means of immunohistochemical method, DNA ladder analysis , flow cytometry quantitive analysis and reverse transcript PCR technology.[Methods] Ninety female 4 weeks NOD mice (20g) were randomly divided into three equal groups. Group1 mice received the intraperitoneal injection of rolipram (8mg/kg) twice every day. Group2 mice received the intraperitoneal injection of PBS equal quantity and times. Group3 mice were as a normal group. Group1 and Group2 experimental mice were administered the intraperitoneal injection of cyclophosphamide (200mg/kg) to accelerate the process of diabetes on day 1 and 14. All mice were killed on day 30 to observe the incidence of diabetes , the degree of insulitis and the expressions of Bcl-2 , Bax , TGF-β 1 and PDX-1 detected with immunohistochemical technology , the distribution of T lymphocytes in thymus and spleen detected by flow cytometry quantitive analysis and the apoptosis rate of T lymphocytes in spleen detected by DNA ladder qualitative analysis and by flow cytometry quantitive analysis. The production of IL-2,IFN-γ,IL-4, IL-10 mRNA was detected by reverse transcript PCR technology.[Results] Intraperitoneal injection of rolipram to NOD mice reduced the incidence of diabetes. The insulitis score and the severity of insulitis were lower in rolipram group than in PBS group. However, The ratio of Bc1-2/Bax, the apoptosis rate of T lymphocyte and the expression of TGF-β1 were higher in rolipram group than in PBS group. The expression of PDX-1 in pancreaticislets isn't associated with rolipram. There are the shift from CD4+Th1 to CD4+Th2 cells in spleens in rolipram group. [Conclusions]:1.Rolipram can prevent NOD mice from developing into type 1 diabetes by increasing apoptosis of T lymphocyte or by shifting increasingly from CD4+Th1 to CD4+Th2 cells.2.Rolipram can decrease expression of Bc1-2 in lymphatic tissue , on the contrary, increase it in pancreatic tissue.3.Rolipram can increase CD4+CD8- and decrease CD4+CD8+ in thymus and increase CD4+ in spleen. However, CD4-CD8+, CD4-CD8-, CD8+ and CD3+ aren't associated with Rolipram.4.Rolipram can increase expression of I1-4, I1-10 mRNA and decrease IFN-γ, I1-2 mRNA to protect pancreatic islets β cells.