Aquaporin 1 (AQP1) Expression in Healthy Dog Tears
Department of Veterinary Medicine and Animal Production, University of Naples Federico II, 80137 Naples, Italy
Department of Advanced Biomedical Sciences, University of Naples Federico II, 80131 Naples, Italy
Institute of Biostructures and Bioimaging (IBB), National Research Council (CNR), 80131 Naples, Italy
Author to whom correspondence should be addressed.
Received: 30 March 2020 / Revised: 6 May 2020 / Accepted: 7 May 2020 / Published: 9 May 2020
The characterisation of tear proteins is very important for scientists and clinicians, as it enhances their understanding of ocular physiological phenomena that sometimes evolve into diseases. Recently, ophthalmic research has been focused on aquaporins (AQPs), a family of water channel proteins that are largely ubiquitous in body tissues and are known for their role in water and small solute transport across cell membranes. Based on AQPs’ presumable role in the eye, the aim of the present study was to investigate the expression of aquaporin-1 (AQP1) by Western blot analysis in canine eye tears. To this end, we collected tears from both eyes of 15 healthy dogs by employing two tear collection methods: Schirmer tear strips (STS) and ophthalmic sponges (OS). Moreover, ocular parameters such as Schirmer tear test 1 (STT 1), intraocular pressure (IOP), and tear film break up time (BUT) were measured, and fluorescein and lissamine green staining were performed to uncover possible correlations among the aforementioned parameters. Our results showed that the expression of AQP1 in tears collected by both methods and expressed as multiple bands (measured by densitometry) was higher for the tears collected by OS than for those collected by STS. This work forms the basis of future studies aiming to understand and establish the involvement of AQPs in the production and secretion of tears.