Protein microanalysis of animal tears
S. HEMSLEY*, N. COLE*†, P. CANFIELD*, M. D. P. WILLCOX†
*Department of Veterinary Anatomy and Pathology, University of Sydney, Sydney, NSW 2006, Australia,
†Cooperative Research Centre for Eye Research and Technology and Corneal and Contact Lens Research Unit, School of Optometry, University of New South Wales, Sydney, NSW 2052, Australia
Sub-microlitre volumes of normal koala, mouse, dog, rat and cat tears were fractionated using size exclusion-high performance liquid chromatography (SE-HPLC), giving reproducible profiles which were different for each species. Microlitre volumes of tears were also fractionated using sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE), resulting in good separation of individual tear proteins with a species specific distribution. Tears from koalas with conjunctivitis and mice with keratitis were similarly examined and showed mostly quantitative changes. These simple, rapid techniques gave reproducible results and, in contrast to conventional separation techniques, used easily obtainable volumes (as little as 0·75µl) of tears. Their expansion could allow isolation, identification and quantitation of individual tear components, enabling effective investigation of changes occurring in disease.