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Previous issue date: 2016-06-14 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A dengue ? a mais importante arbovirose que afeta o homem e constitui-se em
um grave problema de sa?de p?blica. A doen?a ? end?mica em regi?es
tropicais e subtropicais, abrangendo mais de 100 pa?ses, correspondendo ?
metade da popula??o mundial. As epidemias s?o recorrentes e estima-se que
os v?rus da dengue causem 390 milh?es de infec??es a cada ano, sendo uma
importante causa de morbidade. Apesar desse cen?rio, atualmente, ainda n?o
se disp?e de um antiviral contra a dengue. Neste contexto, diversos estudos
relatam a atividade antiviral dos polissacar?deos sulfatados obtidos das algas
marinhas contra v?rus envelopados, cuja a??o est? associada ? interfer?ncia
nas etapas iniciais do processo de infec??o viral. Neste estudo, avaliou-se a
potencial atividade antiviral de extratos brutos ricos em polissacar?deos
sulfatados obtidos das algas marrons Dictyota menstrualis (EBDMens) e
Dictyota mertensii (EBDM) e das algas verdes Codium isthmocladum (EBCI) e
Caulerpa sertularioides (EBCS) contra o v?rus dengue 2 (DENV-2), em
linhagem de c?lulas Vero, usando diferentes estrat?gias metodol?gicas
(tratamento simult?neo, tratamento p?s-infec??o, pr?-tratamento da c?lula, pr?tratamento
do v?rus, adsor??o, p?s-adsor??o e penetra??o). A citotoxicidade
dos extratos foi analisada pelo ensaio de redu??o do MTT. O estudo da
atividade antiviral foi determinado pela quantifica??o do n?mero de c?pias do
RNA viral por RT-qPCR ap?s 120 h de infec??o. Nenhum extrato exibiu
toxicidade para as c?lulas Vero no ensaio de redu??o do MTT na concentra??o
de 100 ?g/mL. Todos os extratos exibiram atividade antiviral quando
adicionados durante os primeiros 90 minutos de infec??o, demonstrando
redu??o significativa no n?mero de c?pias do RNA viral ap?s 120 horas. Os
extratos EBDMens e EBDM foram mais eficazes nos ensaios de pr?-tratamento
da c?lula e do v?rus, e o primeiro exerceu atividade antiviral superior ao EBDM
durante a adsor??o viral. Os extratos EBCI e EBCS apresentaram atividade
antiviral semelhante no ensaio de pr?-tratamento da c?lula. O EBCI foi mais
eficaz na redu??o da adsor??o do DENV-2 em c?lulas Vero. Por?m, o EBCS se
mostrou mais eficiente nos ensaios de pr?-tratamento do v?rus e penetra??o.
Dentre os extratos avaliados, o EBCS parece ser o mais efetivo no combate ao
DENV-2. Estes resultados revelam o potencial desses extratos ricos em
polissacar?deos sulfatados como compostos com a??o antiviral, sugerindo que
eles atuam nos est?gios iniciais da infec??o por DENV-2. / Dengue is considered the most important human arboviruses, and is a serious
public health problem. This disease is endemic in tropical and subtropical
regions, reaching more than 100 countries, which means the half of world
population, and those epidemies have been appellant. It is estimated that
Dengue virus could cause 390 millions of infections each year, and is an
important cause of morbidity. Although this scenario, actually doesn?t exist a
dengue antivirals still. Sorts of studies have showed antivirus activity of
seaweed sulfated polysaccharides against enveloped viruses, which action
seems to be associated to initials steps of infection process. In this study, was
evaluated the potential antiviral activity of crude extracts rich in sulfated
polysaccharides obtained from the brown algae Dyctiota menstrualis
(EBDMens) and Dyctiota mertensii (EBDM), and green algae Codium
isthmocladium (EBCl) and Caulerpa sertularioides (EBCS), tested against
Dengue virus 2 (DENV-2) in Vero cell line, by using different methodological
strategies (simultaneous treatment, post-infection treatment, cell pre-treatment,
virus pre-treatment, adsorption, post-adsorption and penetration). The extracts
cytotoxicity was evaluated by MTT reduction assay. The study of antiviral
activity was determinated by quantifying viral RNA load using RT-qPCR, after
120 hours of infection. None extract has showed toxicity against Vero Cells in
MTT reduction assay with 100 ?g/mL concentration. All extracts have shown
antiviral activity when added during the first 90 minutes of infection, and a
significant reduction of viral RNA number of copies after 120 hours. The
EBDMens and EBDM extracts were more efficient to cell and virus pretreatment
assays, and the first has showed higher antiviral activity than EBDM
during viral adsorption. The EBCI and EBCS extracts have presented antiviral
activity very similar in cell pre-treatment assay. EBCI was more efficient in the
reduction of DENV-2 adsorption in Vero cell. However, EBCS has showed more
efficient in cell pre-treatment and penetration assays. Between the extracts
evaluated, EBCS seems to be more effective against DENV-2. These results
have showed potential action of extracts rich in sulfated polysaccharides with
antivirus activity, suggesting that they act in the initials steps of infection
process of DENV-2.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/21832 |
| Date | 14 June 2016 |
| Creators | Bezerra, Fabiana Lima |
| Contributors | 76111830449, Farias, Eduardo Henrique Cunha de, 01164378473, Fernandes, Jos? Verissimo, 09457135415, Costa, Leandro Silva, 04647720446, C?mara, Rafael Barros Gomes da, 06156497420, Fernandes, Thales Allyrio Ara?jo de Medeiros, 02751517439, Farias, Kleber Juvenal Silva, Rocha, Hugo Alexandre de Oliveira |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM BIOQU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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