Related Experiment Video
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, USA.
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:
Tear fluid samples 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 the biomaRt package to enable comparative cross-species analysis.
Results:
A total of 5270 human and 3876 rabbit proteins were detected across the cohorts, of which 4481 and 3514, respectively, were detected in at least 5 of 10 samples. Ortholog mapping identified 2267 human-rabbit ortholog pairs, while 2214 human and 1181 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 to evaluate their potential for future therapeutic strategies aimed at reducing excessive tear evaporation in humans.
