Epigallocatechin-3-gallate modulates antioxidant and DNA repair-related proteins in exocrine glands of a primary Sjogren's syndrome mouse model prior to disease onset

The autoimmune disorder primary Sjogren's syndrome (SS) is associated with xerostomia and xerophthalmia. SS pathogenesis involves both genetic/epigenetic and environmental factors. A major potential contributor is oxidative stress associated with damage to cellular components, including DNA. We reported previously that the green tea polyphenol epigallocatechin-3-gallate (EGCG) normalizes the elevated levels of proliferating cell nuclear antigen (PCNA), a key component of DNA repair, in the NOD mouse model for SS and type 1 diabetes. The current study examined levels of the antioxidant enzymes peroxiredoxin 6 (PRDX6), catalase and superoxide dismutase (SOD), as well as PCNA, in NOD.B10.Sn-H2 mice, a model for primary SS, and determined the effect of EGCG on their expression. PCNA elevation was detected in the submandibular gland and pancreas by 8 weeks of age in water-fed mice, and increased through 14 weeks of age, prior to overt onset of symptoms. This early PCNA elevation was followed by a decline of pe...