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Updated: Sep 25, 2026
A Protein Suspension-Trapping Sample Preparation for Tear Proteomics by Liquid Chromatography-Tandem Mass Spectrometry
Published on: December 1, 2023
Species-specific tear proteomic signatures in humans and rabbits: A DIA mass spectrometry comparative study
Sunay Kamalasanan1, Saleh Ahmed1, Victoria Clifton1
1Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912.
Purpose:
Rabbits exhibit an exceptionally low blink frequency and a markedly prolonged tear breakup time compared with humans. These physiological differences suggest the presence of specialized tear-stabilizing mechanisms that may be reflected in the molecular composition of rabbit tear fluid. This exploratory study compared human and rabbit tear proteomes to identify shared and species-associated differences potentially relevant to tear film stability and ocular surface homeostasis.
Methods:
Basal tears were collected from 10 healthy human subjects and 10 healthy New Zealand White rabbits using Schirmer strips. Tear proteins were analyzed by liquid chromatography-tandem mass spectrometry. Orthologous proteins were mapped using `biomaRt` package to enable comparative cross-species analysis.
Results:
A total of 5,270 human and 3,876 rabbit proteins were detected across the cohorts, of which 4,481 and 3,514, respectively, were detected in at least 5 of 10 samples. Ortholog mapping identified 2,267 human-rabbit ortholog pairs, while 2,214 human and 1,181 rabbit proteins remained unmatched. Human tears were enriched in proteins associated with mucosal immunity and antimicrobial defense, including lysozyme C, lactotransferrin, lipocalin-1, lacritin, and immunoglobulins. In contrast, rabbit tears showed enrichment of proteins associated with lipid handling, antioxidant defense, and epithelial maintenance, including lipocalin-related proteins, lipophilins, uteroglobin, glutathione S-transferases, peroxiredoxin-6, and several uncharacterized proteins with predicted lipophilin/secretoglobin-like features.
Conclusions:
Human and rabbit tears share a conserved core proteome while exhibiting distinct species-associated proteomic profiles. Rabbit-enriched proteins warrant further functional investigation to determine their roles in tear film stability and evaluate their potential for future therapeutic strategies aimed at reducing excessive tear evaporation.
