Work

Evaluation of anti-viral photodynamic therapy effects of different concentrations of 5-ALA using light irradiation on HSV-1

Year: 2024

Type: article

Abstract: • This study aims to use 5-ALA-based photodynamic therapy (PDT) for HSV-1 eradication. • 5-ALA-based PDT significantly reduces HSV-1 viral titers. • A combination of 0.1 g/ml 5-ALA treatment with 630 nm laser radiation shows the most significant virus titer reduction. • Lower concentrations of 5-ALA do not effectively eliminate HSV-1. • PDT with 5-ALA may present a potential treatment option for HSV-related antiviral-resistant infections. Herpes simplex virus (HSV) infections are prevalent worldwide, posing challenges due to asymptomatic carriage and recurrent outbreaks. Conventional treatments, including antiviral medications, are limited by drug resistance. Photodynamic therapy (PDT) offers a promising alternative, leveraging photosensitizers to induce viral inactivation via reactive oxygen species (ROS) generation upon light activation. This study investigates the efficacy of 5-aminolevulinic acid (5-ALA) as a photosensitizer in antiviral PDT against HSV-1. HSV-1 was treated with varying concentrations of 5-ALA and subjected to light irradiation at a 630 nm wavelength. Virus titers were assessed using the 50 % Tissue Culture Infectious dose (TCID50) assay. Six experimental groups were used: [ 1 ] Control (no 5-ALA or light), HSV-1 with 0.05 g/ml 5-ALA and 630 nm light, [ 2 ] HSV-1 with 0.05 g/ml 5-ALA (no light), [ 3 ] HSV-1 with 0.1 g/ml 5-ALA and light, [ 4 ] HSV-1 with 0.1 g/ml 5-ALA (no light), and [ 5 ] HSV-1 with light (no 5-ALA). Virus treatment with 0.1 g/ml 5-ALA combined with light irradiation significantly reduced HSV-1 titer compared to control groups ( p < 0.05). Specifically, the virus titer decreased from 10 6.3 TCID50/ml in the control group to 10 4.5 TCID50/ml in the treated group. However, lower concentrations of 5-ALA or light irradiation alone did not yield significant reductions in HSV-1 titer ( p > 0.05). Group 4, receiving 0.1 g/ml 5-ALA with light irradiation, exhibited a significantly greater reduction in virus titer than group 2, receiving 0.05 g/ml 5-ALA with light irradiation ( p < 0.05). 5-ALA-mediated PDT demonstrates selective antiviral efficacy against HSV-1, particularly at higher concentrations coupled with light irradiation. These findings underscore the potential of 5-ALA-based PDT as a promising approach for HSV-1 treatment, especially in cases of drug-resistant strains and immunocompromised individuals. Optimization of dosage and treatment protocols is essential for maximizing effectiveness in clinical applications, highlighting the need for further research in this area.

Source: Photodiagnosis and Photodynamic Therapy

DOI: 10.1016/j.pdpdt.2024.104365