Investigação dos Efeitos Antivirais do Canabidiol na Infecção pelo Vírus Chikungunya

Abstract

The infection caused by the Chikungunya virus (CHIKV) represents an emerging threat and its insect vectors, Aedes aegypti and albopictus, are well established in various regions of the planet, so epidemics of the disease are recorded globally. Typical symptoms caused by CHIKV infection include fever, headache, joint swelling and itching, while in the chronic phase, the main symptom is arthralgia. To date, there are no vaccine therapies for CHIKV infection, and treatments focus solely on palliative measures. Therefore, the search for effective therapies is crucial to mitigate the spread of CHIKV and minimize its impact on public health. In this sense, cannabidiol (CBD), one of the active compounds present in Cannabis sativa, has been widely studied for its therapeutic potential in inflammation and viral infections. Therefore, this study aims to investigate and understand the antiviral mechanisms associated with CBD in CHIKV infection. To this end, an in vitro culture of the Vero cell line was established and CHIKV infection was subsequently induced using a reporter virus system that incorporates the fluorescent protein mCherry into the viral genome (CHIKV-mCherry). Using fluorimetry and confocal microscopy, the expression of mCherry was monitored in the infected cells. In addition, the toxicity of CBD on Vero cells was assessed by the WST-8 colorimetric assay, using four different concentrations (1, 3, 10 and 30 μM). The concentration of 3 μM of CBD was used in the subsequent experiments. In order to assess the antiviral efficacy of CBD, Vero cells were then treated with CBD and CHIKV in four experimental groups: I. Mock (Uninfected), II. CHIKV (Virus), III. CBD + CHIKV (pre-treatment, carried out 24, 12, 8, 6 and 2 hours before infection) and IV. CHIKV + CBD (posttreatment, carried out 2 hours after infection). Twenty-four hours after infection, the effectiveness of these treatments was evaluated. A reduction in viral load and replication was observed in CBD-treated cells after infection with CHIKV, connoted by the lower expression of mCherry in confocal microscopy analysis. There was also a reduction in cytopathic effects (set of changes caused by the virus in infected cells) in the CBD-treated group after infection, as well as very little modulation of viral infection in the pre-infected groups. The results indicate the effectiveness of CBD in reducing CHIKV infection, probably due to its immunomodulatory properties. This makes CBD a potential candidate for use in the treatment of CHIKV infections.