Effects of oral consumption of the green tea polyphenol EGCG in a murine model for human Sjogren’s syndrome an autoimmune disease

摘要

Protection of glandular acinar cells from autoimmune-induced damage would be of significant clinical benefit to Sjogren’s syndrome (SS) patients. EGCG (the most abundant green tea polyphenol) possesses anti-apoptotic, anti-inflammatory, and autoantigen-inhibitory properties. To investigate if EGCG can protect against certain autoimmune-induced pathological changes in the salivary glands of the non-obese diabetic (NOD) mouse model for SS-like symptoms, animals were provided with either water or water containing 0.2% EGCG. At the age of 8, 16 and 22 weeks, samples were collected for pathological and serological analysis. Massive lymphocyte infiltration was observed in the salivary glands of the water-fed group at the age of 16 weeks, while the EGCG group showed significantly reduced lymphocyte infiltration. By 22 weeks of age, animals fed with water demonstrated elevated levels of apoptotic activity within the lymphocytic infiltrates, and high levels of serum total anti-nuclear antibody, in comparison with the animals fed with EGCG. Remarkably, proliferating cell nuclear antigen (PCNA) and Ki-67 levels in the salivary glands of NOD animals fed with water were significantly elevated in comparison to BALB/c control mice; in contrast, PCNA and Ki-67 levels in EGCG-fed NOD animals were similar to BALB/c controls. These results indicate that EGCG is able to protect the NOD mouse submandibular glands from autoimmune-induced inflammation, and reduces serum autoantibody levels. Abnormal proliferation, rather than apoptosis, appears to be a characteristic of the NOD mouse gland that is normalized by EGCG. The evidence suggests that EGCG could ultimately be used to delay or manage SS-like autoimmune disorders.