Lycium barbarum Polysaccharide Ameliorates Sjögren's Syndrome in a Murine Model.

Scope Lycium barbarum polysaccharide (LBP) has demonstrated several immune regulatory and anti-inflammatory effects. This study aims to evaluate the therapeutic efficacy and mechanisms of LBP treatment in primary Sjogren's syndrome (pSS). Methods and results Non-obese diabetic (NOD) mice were randomly divided into four groups: low dose LBP (LBP.L, 5 mg/kg/d), high dose LBP (LBP.H, 10 mg/kg/d), low dose interleukin (IL)-2 (LDIL-2, 25000 IU/d), and control (saline water). LBP, saline water, and IL-2 were administered daily for 12 weeks. Salivary flow rate, histological alterations, T cells subpopulations, autoantibody levels were each examined. Low dose LBP significantly reduced the salivary gland inflammation compared with the control group (histological score: p LBP.L versus Control = 0.019; foci number: p LBP.L versus Control = 0.038). Low dose LBP also remarkably reduced the effector follicular helper T (Tfh) cells and the CD4+ IL-17A+ helper T (Th17) cells in both spleen and the cervical lymph node (cLN) cells. Additionally, the ratios of Treg/Tfh cells and Treg/Th17 cells were substantially increased in mice treated with low dose LBP in both the spleen and cLNs. LBP also inhibited the Th17 and Tfh cells and markedly increased the Treg/Tfh ratio in human peripheral blood mononuclear cells. Conclusion Low dose LBP inhibits the progression of pSS in this mice model in part via T cell differentiation modulation. This article is protected by copyright. All rights reserved.