Disseleneto de difenila em modelos de infecção viral causada por herpes simplex vírus dos tipos 1 e 2

Abstract

Infectious diseases caused by herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) are among the pathologies that most affect the population. The search for new therapeutic alternatives for its treatment becomes relevant due to the growth of cases resistant to Aciclovir, a reference in the treatment of herpetic infections. Thus, this thesis investigated the effect of diphenyl diselenide (PhSe)2, an organic molecule of selenium, for the treatment of infections caused by herpes simplex virus 1 (HSV-1) and 2 (HSV-2) in vitro and in vivo. In the protocol 1 related to articles 1 and 2, the cell viability test (MTT) was initially performed to check the toxicity of the compound (1-100 μM) and later its effect on the virus was verified by the plaque reduction assay, both tests performed on VERO cell culture. After, the experiments were carried out in vivo. The protocol consisted of treatment with (PhSe)2 (5 mg/kg/day, intragastric, i.g.) 5 days before and 5 days after infection; mice were infected at day 6. The extravaginal lesion score was evaluated from days 6 to 10. At the end of treatments, the animals were killed and ex vivo analyses of the genital, renal, hepatic and plasma tissues were performed. Other parameters were also investigated such as viral load, histological analysis, oxidative stress, inflammation, immune response, antioxidant and anti-inflammatory enzyme activities, renal and hepatic toxicity parameters. In the protocol 2 related to the manuscript 1, the antiviral effect of (PhSe)2 against HSV-1 infection was investigated at different times post-infection (4 and 24 hours) in glial culture cells. The viral load was quantified through plaque reduction assay, inhibition of viral DNA synthesis and inhibition of genes involved in the replicative cycle (ICP27, ICP0, ICP8 and viral DNA polymerase). The activation of the immune system (NF-κB and TNF-α) in HSV-1 infected cells was also investigated. The results of articles 1 and 2 demonstrated an antiviral effect of (PhSe)2 in vitro and in vivo as well as the reduction of oxidative stress, inflammation and restoration of antioxidant capacity, such as the content of non-protein thiols and the activity of antioxidant enzymes. Furthermore, the compound protected against toxic effects generated by infection at the renal and hepatic levels. The results obtained in manuscript 1 were also positive because the antiviral effect of (PhSe)2 against HSV-1 infection in glial cells was confirmed as well as the reduction of viral DNA synthesis and regulation of the replicative cycle genes. The compound reduced the expression of most viral genes studied at different time points after infection. (PhSe)2 showed an immunomodulatory effect by reducing the expression of the cytokine TNF-α. From these data, (PhSe)2 can be considered an important therapeutic alternative to treat HSV-1 and HSV-2 infections.