Immunolocalization of AQP5 in resting and stimulated normal labial glands and in Sjogren's syndrome.

Abstract

OBJECTIVE: In our current work in vivo examination of AQP5 distribution in labial salivary glands following stimulation of secretion has been done in normal individuals and in Sjogren's syndrome patients. SUBJECTS AND METHODS: For this study, we selected 5 patients with primary Sjogren's syndrome (mean age 62,4 + 10,6 SD years) diagnosed in accordance with the European Cooperative Community classification criteria. There were 5 patients (mean age 27 + 2,5 SD years) in the control group. The subcellular distribution of AQP5 in human labial gland biopsies was determined with light and immunoelectron microscopy before and 30 min after administration of oral pilocarpine. RESULTS: In unstimulated control and Sjogren's labial glands AQP5 is about 90% localized in the apical plasma membrane, with only rarely associated gold particles with intracellular membrane structures. We have found no evidence of pilocarpine-induced changes in localization of AQP5 in either healthy individuals or Sjogren's patients. CONCLUSIONS: Our studies indicate that neither Sjogren's syndrome itself, nor muscarinic cholinergic stimulation in vivo caused any significant changes in the distribution of AQP5 in the labial salivary gland cells. This article is protected by copyright. All rights reserved.