Establishment and characterization of salivary gland-specific injury in transgenic mice model.

Introduction: Many mouse models for autoimmune diseases also have lesions in non-target organs, which may make it difficult to determine whether the target organ lesion is primary or secondary. Hyposalivation has conventionally been studied using genetically modified mouse models for Sjogren's syndrome as well as spontaneous autoimmune mice with systemic lesions, none of which has salivary gland-specific injury.

Methods: In this study, we established a salivary gland-specific injury mouse model using the TRECK system by gene modification with the transgene composed of the 5' untranslated region of human salivary mucin gene MUC7 (highly expressed specifically in human salivary gland) inserted at the upstream of hHB-EGF (diphtheria toxin receptor) in the TRECK vector.

Results: In this transgenic mouse model, we confirmed salivary gland-specific expression of hHB-EGF gene, and hyposalivation after treatment with diphtheria toxin. Histological assessment of the salivary gland from these mice showed granular convoluted tubule epithelial cells destruction at the same position as a positivity in TUNEL assay.

Conclusion: This transgenic mouse model may become a useful tool for elucidating the mechanisms involved in hyposalivation and for developing pharmaceuticals and tissue regenerative medical products for this condition.