Diverse Roles of Natural Killer T Lymphocytes in Liver and Spleen in Mice with Experimental Autoimmune Uveitis

Cytotoxic effect of specific T cells from mice with experimental autoimmune uveitis on murine photoreceptor cells

AIM

To investigate the cytotoxic effect of specific T cells from mice with experimental autoimmune uveitis (EAU) as well as their secreted interferon (IFN)-γ and interleukin (IL)-17A on murine photoreceptor (661W) cells.

METHODS

An EAU model was established in female mice by injection of interphotoreceptor retinoid binding protein (IRBP) emulsion supplemented with complete Freund's adjuvant (CFA) and Mycobacterium tuberculosis (TB). On day 12 after induction of EAU, specific T cells from spleen and lymph node tissues were isolated and cultured for 4d and the levels of IFN-γ and IL-17A in the supernatants were determined by enzyme-linked immunosorbent assays (ELISAs). T cells and their supernatants were added to 661W cells to observe the alteration of cell morphology; IFN-γ and IL-17A were separately added to 661W cells to observe the effect of IFN-γ and IL-17A on cell proliferation.

RESULTS

The levels of IFN-γ and IL-17A in the T cell supernatants were 1568.64±38.79 pg/mL and 1456.57±46.98 pg/mL, respectively. The supernatants apparently inhibited 661W cell proliferation (P<0.05). T cells could also attach to the surface of 661W cells, and IFN-γ showed a more serious cytotoxic effect on 661W cells than IL-17A, inhibiting cell proliferation (P<0.01).

CONCLUSION

IFN-γ and IL-17A from T cells of EAU mice model can exert cytotoxic effects on murine photoreceptor cell proliferation, and IFN-γ shows more serious cytotoxic effects on murine photoreceptor cells than IL-17A.

Protective effect of platycodin D on liver injury in alloxan-induced diabetic mice via regulation of Treg/Th17 balance

Platycodin D is a major pharmacological constituent of Platycodi Radix with immunomodulatory activity. The present study was designed to investigate how platycodin D (PLD) reveals liver injury in diabetic mice and its mechanism. Fifty mice were divided into five groups randomly: control group, model group, rosiglitazone (ROG, 10 mg/kg) group, PLD (50 mg/kg) group, and PLD (100 mg/kg) group. Diabetes was induced with the injection of alloxan monohydrate (150 mg/kg) subcutaneously, and animals with blood glucose level of ≥250 mg/dl were considered as diabetic mice. After the first day of diabetes induction, the treatments were performed for 8 weeks. Then the animals were anaesthetized, and blood and liver samples were also collected for further assay. PLD significantly decreased the serum levels of glucose, insulin, interleukin-6 (IL-6), interleukin-1β, tumor necrosis factor-α (TNF-α), and interleukin (IL)-17A and increased IL-10 level in serum. PLD effectively downregulated aspartate transaminase (AST), alanine aminotransferase (ALT), total cholesterol (TC), and triglycerides (TG) in liver. PLD also attenuated liver histological change. In addition, PLD significantly attenuated IL-17A and IL-10 levels in vitro, flow cytometry (FCM) studies also showed that PLD remarkably inhibited Th17 cells and significantly increased Treg cells in liver tissues and spleen cells. Western blot demonstrated PLD inhibited the phosphorylation of JAK and STAT-3 and the expression of RORγt and increased the expression of Foxp3. The findings showed that PLD exerts beneficial effects on alloxan-induced liver injury in mice.