Analyzing Tear Fluid Composition by Synchronous Fluorescence for Diagnosing Dry Eye Disease and the Role of Phytotherapy Intervention

Abstract

Purpose

Tear fluid gained attention as a representative biological fluid. Its simple and non-invasive collection methods as well as richness of candidate biomarkers made it a potential diagnostic tool for different diseases such as dry eye. Synchronous fluorescence spectroscopy is a highly sensitive analytical tool that results in narrowing and enhanced peak resolution, and has a potential role in disease diagnosis, biomarker identification, and therapeutic monitoring. We applied synchronous fluorescence spectroscopy to monitor variations of tear fluid composition during the development of dry eye disease and to evaluate the potential effects of phytotherapy.

Methods

Dry eye model was induced in Chinchilla rabbits by instillation of 1% atropine sulfate ophthalmic solution. Then, the tear fluid was collected at 3, 7, and 14 days and subjected to synchronous fluorescence spectroscopy. Phytotherapy was achieved by topical instillation of 20 µl of water extracts of pomegranate peel or green tea powders.

Results

The fluorescence results revealed changes in the structure of tear fluid over time and the eye is subjected to toxification due to oxidative stress. In addition, dry eye disease was found to affect the metabolic/energetic state of the eye. On the other hand, phytotherapy led to enhancement of the metabolic/biosynthesis state due to activation of flavin adenine dinucleotide-associated proteins.

Conclusion

There was change in the electrical conductivity of tear fluid proteins. In the case of dry eyes, they became electrical insulators, while in the case of treatment with extracts, their electrical conductivity properties improved. The effects of phytotherapy can be related to the high content of ellagic acid and anthocyanin of pomegranate extract, while in green tea, they are related to catechins and phenolic compounds.

Keywords:

• Dry eye
• synchronous fluorescence
• tear fluid
• phytotherapy
• biophysics

Author contributions

Shaimaa M. Moussa: sampling, methodology, resources, and writing. Sherif S. Mahmoud: supervision, conceptualization, methodology, resources, investigation, and writing – review and editing. Eman M. Aly and Mona S. Talat: supervision, methodology, investigation, resources, and writing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data are included within the article.

Additional information

Funding

This research did not receive any specific grant from funding agencies.