Effects of water-filtered infrared A and visible light (wIRA/VIS) radiation on heat- and stress-responsive proteins in the retina and cornea of guinea pigs.

Antonia Frohns,Marijana Stojanovic,Talin Barisani-Asenbauer,Aleksandra Inic-Kanada,Nicole Borel,Jasmin Kuratli

doi:10.1016/j.jphotobiol.2021.112306

Abstract

Water-filtered infrared A and visible light (wIRA/VIS), shown to reduce chlamydial infections in vitro and in vivo, might represent an innovative therapeutic approach against trachoma, a neglected tropical disease caused by ocular infection with the bacterium C. trachomatis. In this in vivo study, we assessed the impact of wIRA radiation in combination with VIS (wavelength range 595-1400 nm, intensity 2100 W/m2) on the retina and cornea in a guinea pig animal model of inclusion conjunctivitis. We investigated the effects 19 days after wIRA/VIS irradiation by comparing a single and double wIRA/VIS treatment with a sham control. By immunolabeling and western blot analyses of critical heat- and stress-responsive proteins, we could not detect wIRA/VIS-induced changes in their expression pattern. Also, immunolabeling of specific retinal marker proteins revealed no changes in their expression pattern caused by the treatment. Our preclinical study suggests wIRA/VIS as a promising and safe therapeutic tool to treat ocular chlamydial infections.

Highlights

Trachoma is an ocular disease caused by infection with the bacterium C. trachomatis (Ct)
This study is a follow-up to our previous study where we showed that Water-filtered infrared A (wIRA)/visible light (VIS) can efficiently combat chlamydial infection [21]
The model’s main advantage is that changes in the conjunctiva of individual animals throughout infection can be assessed by gross pathology and can be correlated to the number of bacteria isolated from ocular swabs

Summary

Introduction

Trachoma is an ocular disease caused by infection with the bacterium C. trachomatis (Ct). The commonly used therapy for ocular Ct infection relies on antibiotic treatment with azithromycin, mostly applied via mass drug administration in endemic regions [2]. This treatment has disadvantages in terms of potential antibiotic resistance development and adverse drug reactions [4,5]. Persistent stages of Ct are less susceptible to antibiotic treatment and may result in long-term Ct infection with ongoing chronic inflammatory processes [6,7] For these reasons, alternative non-chemical treatment options are needed to eliminate trachoma

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Results

Conclusion