An autoimmunized mouse model recapitulates key features in the pathogenesis of Sjögren's syndrome

The pathogenesis of Sjögren's syndrome (SS) is poorly understood. To evaluate an autoimmunization-induced experimental SS model, we firstly observed the phenotype of lymphocyte infiltration in the enlarged submandibular gland (SG). Furthermore, significant activation of caspase-3 and a high ratio of Bax-to-Bcl-2 were detected, indicating the inflammatory apoptosis associated with developmental foci. Meanwhile, the dysregulated cytokines, such as tumor necrosis factor α, IL-1β and IL-6 mRNA expression, were found to be over-expressed. A progressive decrease of aquaporin 5 and its subcellular translocation from apical to basal membrane in SG was found to be associated with the abnormally expressed M3 muscarinic acetylcholine receptor. This pattern was found to be similar to that seen in human SS and possibly contributed to the saliva secretion deficiency. Thus, this autoimmunization-induced model recapitulates the key features of human SS and may have potential for studying the pathogenesis of human SS.