Evaluation of blue light therapy in treating viral pulmonary infection with a viral surrogate and lung cells

Abstract

RNA viruses can cause severe diseases, which necessitates finding effective treatment of viral infection. Anti-microbial blue light therapies, whose effectiveness has been proved in inhibiting bacteria and fungi, can also be an alternative. However, few studies have been devoted to antiviral blue light therapies so far. Efforts have been made in this work to especially investigate the suitability of blue light in treating viral infections in lungs. First, for bio-safety concerns, experimental methods using lentiviral vectors as the surrogates for hazardous RNA viruses were developed. The lung fibroblast cell line (MRC-5) was adopted as the host cells. Second, various experimental and dosimetric parameters were applied and compared, which showed that the 415 nm light at 27 J cm−2 provided the best therapeutic effect among the three candidates of 405, 415 and 450 nm, without compromising the viability of the host cells. Third, the intracellular reactive oxygen species (ROS) were measured, which proved that although the blue light cannot directly induce toxicity to the virus, the therapeutic effects of the blue light are actually attributed to the toxic ROS generated via the host cells. More interestingly, a strong correlation between the viral inactivation data and the light induced ROS levels in the host cells was discovered, independent of the wavelength. In conclusion, the effectiveness of the antiviral blue light therapy has been demonstrated in the early treatment of viral pulmonary infection.