Effects Of Tea Polyphenols On Sj(?)gren's Syndrome In NOD Mice

[Background] Sjogren's syndrome(referred to as:SS) is a systemic autoimmune disease of unknown etiology characterized by persistent dryness of the mouth and eyes. According to the existing population survey data show the prevalence is between in the 0.60%-3.3%, with an incidence of about 4-5 cases per 100, OOO.The current treatment for SS has not yet effective method, general treatment is mainly symptomatic treatment, but long-term use of medication has brought a lot of side effects. Chinese traditional herbal medicine attracted wide attention from scholars. In recent years, scholars are committed to looking to adjust the flow of saliva and effective herbs used in the treatment of Sjogren's syndrome. In China and Japan,green tea consumption is very large, the number of SS in Asian is less than that of people in Europe and America. Moreover, green tea has a good effect on the prevention and treatment of other autoimmune diseases like rheumatoid arthritis and autoimmune encephalomyelitis. The main component of green tea is polyphenols,which mainly composed of catechin compounds. Catechin compounds contain four kinds of monomers: Epigallocatechingallate(EGCG),Epicabechingallate(ECG), Epicatechin (EC) and Epigallocatechin (EGC). EGCG accounts for about 50% catechins and also has the strongest biological effects. Over the past 20 years, a large number of epidemiological and in vivo experiments have confirmed:Green tea has antioxidant, anti-inflammatory, anti-apoptosis, anti-mutagenic, anti-tumor and anti-radiation damage and other biological activities and pharmacological effects. The complexity of the effect of tea polyphenols are concerned by oral researchers. In recent years, some scholars have conducted a preliminary study,and the result gives a support that some effect on its regulation of salivary flow rate. It may work by reducing cytokine. But few are reported about the research on this area in China. Furthermore, on preventive effects of tea polyphenols on SS, there is no report.[Objective] In order to investigate the preventive effect of tea polyphenols on SS and to provide experimental evidence for clinical application of tea polyphenols on the prevention and treatment of SS, we did the folowing studies using the NOD mice as a model for SS:effect on salivary flow rate; effect on antinuclear antibodies and effect on inflammatory factors.[Methods] NOD mice were randomly divided into prevention group and control group.Prevention group mice were fed with water containing tea polyphenols, and control group mice were fed with water as a control. At week 9,16 and 23,8 mice were removed from each group and blood from the mice of both groups were collected and the serum was separated to measure the cytokine levels, and then the mice were killed, the submandibular gland from the mice of both groups were collected and weighed, Each left submandibular gland was fixed in 10% neutral-buffered formalin and paraffin-embedded for pathological analysis. The right ones were stored at-80℃for molecular analysis.(1) At the age of 9,16 and 23 weeks,8 animals from each treatment group were removed randomly and their salivary flow were measured with the wet weight method. (2) giving an analysis of paraffin sections of submandibular gland H.E at the age of 9,16, and 23 weeks respectively. (3) Using ELISA test to measure the antinuclear antibody levels of the serum of each group, (4) Using ELISA test to measure the IFN-γ,IL-4 and IL-17 levels of the serum.[Results] 1. At the age of 16 and 23 weeks, the salivary flow rate of prevention group mice was significantly higher compared to that of control group (P<0.01).2. At the age of 16 and 23 weeks, it was delayed that submandibular gland pathological response of prevention group mice compared to that of control group,and in the prevention group the pathological grade lower 1-2 levels than that of control group in the same period.3. At the age of 16 and 23 weeks, antinuclear antibody levels of the serum of prevention group was significantly lower than that of control group over the same period. (P<0.01).4. At the age of 9,16 and 23 weeks, the IFN-y level of the peripheral blood of NOD mice of prevention group were significantly lower than that of control group (P<0.01), while at the age of 16 and 23 weeks, the IL-4 level of the serum of prevention group were significantly lower than that of the control group (P<0.01).5. IL-17 was detected only in part of the serum of both prevention group and control group.[Conclusion] 1. Tea polyphenols can retard the decrease of salivary flow and alleviate the pathological manifestation of the submandibular gland of NOD mice, so tea polyphenols have certain preventive effects on Sjogren's syndrome of NOD mice.2. The preventive mechanism of tea polyphenols may be associated with the inhibitation of increased levels of the ANA,IFN-γand IL-4 in serum of NOD mice.