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Elevated levels of type I interferon (IFN) during type 1 diabetes mellitus (T1D) are associated with a defective immune response. In the present study, we investigated whether blocking type I IFN signaling during streptozotocin- (STZ-) induced T1D in mice improves lymphocyte proliferation and escape from continuous apoptosis. Three groups of mice were examined: diabetic mice, type I IFN signaling-incompetent diabetic mice, and control nondiabetic mice. We first found that diabetes induction was accompanied by an elevation in the plasma levels of reactive oxygen species (ROS), hydroperoxide, malondialdehyde (MDN), and the proinflammatory cytokines IL-1α, IL-1β, IL-6, and CXCL10. Blocking type 1 IFN signaling in diabetic mice significantly decreased the levels of oxidative stress and proinflammatory cytokines. In addition, lymphocytes from diabetic mice exhibited a marked reduction in their proliferative capacity, increased apoptosis, upregulation of the exhaustion marker PD-1, and aberrant phosphorylation of STAT1, STAT2, AKT and IκB-α. Interestingly, following the blocking of type I IFN signaling in diabetic mice, the lymphocytes exhibited restored proliferative capacity, decreased apoptosis, normal expression of PD-1, and normal phosphorylation of STAT1, STAT2, AKT and IκB-α. Our data suggest that elevated levels of type I IFN during T1D trigger lymphocyte exhaustion and a defective lymphocyte-medicated immune response.

Diazinon (DZN) has been used for several years in agriculture and urban applications leading to a variety of negative effects on health. Hesperidin (HDN) and garlic oil are naturally occurring compounds present in fruits and vegetables, which have been reported to have antioxidants and anti-inflammatory actions. This study was undertaken to throw light on the modulatory effect of HDN or garlic oil against hemato- and immunotoxicity induced by DZN in Wistar rats. Oral administration of DZN for 30 days resulted in significant decrease in RBCs count, Hb content, Ht value, platelet count, and relative lymphocyte and monocyte counts when compared with control groups. Moreover, DZN reduced significantly the serum total immunoglobulin concentration, hemagglutination titer, quantitative hemolysis of SRBCs, delayed type hypersensitivity, blood mononuclear cell proliferation, phagocytic index and blood T-cell subtypes (CD4(+) and CD8(+)) in comparison with vehicle treatment. Co-administration of HDN or garlic oil, 30 min before DZN was able to normalize most of the hematological and immunological parameters. These results suggested that HDN or garlic oil, the natural antioxidants, can alleviate DZN induced hemato- and immunotoxicity.

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Background: The autoimmune disease type 1 diabetes mellitus (T1D) is associated with a defect in the immune response, which increases susceptibility to infection. We recently demonstrated that prolonged elevated levels of type 1 interferon (IFN) induce lymphocyte exhaustion during T1D. Aims: In the present study, we further investigated the effect of blocking the type I IFN receptor signaling pathway on diabetic dyslipidemia, in which an abnormal lipid profile leads to the exhaustion of B cells and alteration of their distribution and functions. Methods: T1D was induced in a mouse model by an intraperitoneal injection of a single dose (60 mg/kg) of streptozotocin (STZ). Three groups of mice were examined: a non-diabetic control group, a diabetic group and a diabetic group treated with an anti-IFN (alpha, beta and omega) receptor 1 (IFNAR1) blocking antibody to block type I IFN signaling. Results: We observed that induction of T1D was accompanied by a marked destruction of β cells and a reduction in the insulin levels in the diabetic group. Diabetic mice exhibited many changes, including alterations in their lipid profiles, expansion of splenic B cells, increased caspase-3, -8 and -9 activity, and apoptosis in peripheral B cells. Blocking type 1 IFN signaling in diabetic mice significantly returned the insulin and lipid profiles to normal levels, subsequently restored the B cell distribution, and rescued the peripheral B cells from apoptosis. Conclusion: Our data suggest the potential role of type I IFN in mediating diabetic dyslipidemia and an exhausted state of B cells during T1D.

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