Link between inflammation and aquaporin-5 distribution in submandibular gland in Sjögren's syndrome?

ABSTRACT

OBJECTIVE: To determine whether a link exists between inflammation and aquaporin-5 distribution in submandibular glands from three animal models for Sjögren's syndrome IQI/JIC, r1ΔT/r2n and non-obese diabetic mice. METHODS: Mice of different ages were used. Inflammatory infiltrates were quantified using the focus score. Acinar aquaporin-5 subcellular distribution was determined by immunohistochemistry and quantified using labelling indices. RESULTS: Minor inflammatory infiltrates were present in r1f/r2n mice. Massive inflammatory infiltrates and acinar destruction were observed in 24-week-old non-obese diabetic mice, 10-and 13-month-old IQI/JIC mice and some r1ΔT/r2n mice. Aquaporin-5 immunoreactivity was primarily apical in submandibular glands from 8- and 24-week-old Balb/C mice, 8-week-old non-obese diabetic mice, 2-, 4- and 7-month-old IQI/JIC mice and r1f/r2n mice. In contrast, decreased apical aquaporin-5 labelling index with concomitant increased apical-basolateral, apical-cytoplasmic and/or apical-basolateral-cytoplasmic aquaporin-5 labelling indices was observed in 24-week-old non-obese diabetic, 10- and 13-month-old IQI/JIC and r1ΔT/r2n mice with a focus score≥1. CONCLUSIONS: Altered aquaporin-5 distribution in submandibular acinar cells from IQI/JIC, non-obese diabetic and r1ΔT/r2n mice with a focus score≥1 appears to be concomitant to the presence of inflammatory infiltrates and acinar destruction.