Salivary gland cytokine expression in NOD and normal BALB/c mice

The autoimmune diabetes-prone nonobese diabetic (NOD) mouse develops a chro nic lymphocytic infiltration of endocrine and exocrine glands. The objectiv es of this study were to characterize the salivary immune infiltration and cytokine expression of NOD mice and compare these findings to those of norm al BALB/c mice. A decline in salivary flow rates in NOD mice began between 8 and 12 weeks of age. At this same time lymphocytic foci are detectable in the salivary glands. Lymphocytic infiltration in the salivary glands of NO D mice increased with age and simultaneously salivary function declined. No lymphocytic infiltration was seen in BALB/c salivary tissues. Messenger RN A expression of several inflammatory cytokines, including interleukin-1 bet a (IL-1 beta), IL-2, IL-10, interferon-gamma, and tumor necrosis factor-cu was detected in the submandibular glands of both NOD and BALB/c mice by the reverse transcription polymerase chain reaction. IL-4 synthesis was also p resent in some tissues. Immunohistochemical analysis demonstrated the inten se expression of inflammatory cytokines within lymphocytic infiltrates and epithelial cells of all NOD mice. Minimal expression of the same cytokines was detected only occasionally in BALB/c tissues stained in parallel. These results demonstrate cytokine expression in the salivary glands of normal m ice and suggest that the overexpression of these inflammatory cytokines is likely involved in the development and progression of the organ-localized a utoimmunity in the salivary glands of NOD mice.