Estudo in vitro e in vivo do efeito probiótico de Weissella paramesenteroides WpK4 no tratamento da infecção causada por Rotavírus

• Ano de defesa: 2018
• Autor(a) principal: Cesar da Silva Santana Moura
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - DEPARTAMENTO DE BIOLOGIA GERAL; Programa de Pós-Graduação em Genética; UFMG
• Palavras-chave em Português: Probióticos; Rotavírus; Weissella; Genética
• Link de acesso: http://hdl.handle.net/1843/64557

Severe diarrhea caused by gastroenteritis, or inflammation of the intestinal mucosa, is still a major global problem, being observed in developed and developing countries. It is one of the most common diseases in the world, affecting people of all age groups. However, it has a higher frequency during the first years of life and is the second leading cause of mortality in the first years of life. The viruses are mainly associated with acute gastroenteritis, among which rotavirus stands out. Rotavirus-induced gastroenteritis is not treated with antibiotics or drugs. Rotavirus presents a wide range of strains and vaccines currently available in the market do not cover all this diversity. Thus, several strains not covered by vaccination contribute to the reemergence of the disease. In the last decades, the modulation of intestinal microbiota has been searched, among the approaches, is the use of probiotics. The great advantage of therapy with probiotics is the absence of side effects, such as the selection of resistant bacteria when antibiotics are used. In this context, probiotics to modulate intestinal microbiota and control diarrhea can be an effective alternative for the treatment of acute gastroenteritis. Weissella paramesenteroides WpK4 showed probiotic action against Salmonella Typhimurium infection in a murine experimental model, so studies involving other enteropathogens become relevant for a better understanding of the protective character of the strain. In this sense, the present study aimed to evaluate the probiotic effect of the WpK4 strain against the infection caused by rotavirus SA11 in vitro in intestinal epithelial cells of the HT-29 lineage, and in vivo, in a murine experimental model. The adhesion and invasion of WpK4 were evaluated in a coculture assay in three cell lines, MA104, HT-29, and Caco-2, using an ROI of 100:1 (WpK4: cell) with 1h of contact. The number of adhered bacteria (internalized) ranged from 4.3 to 5.9 log CFU/ml (2.6-4.0 log CFU/ml). HT-29 cell infection by pre-activated rotavirus SA11 (106 FFU/mL) was evaluated: 1 h before the addition of the bacterium (108 UFC); simultaneously with the bacterium; 30 min after the addition of the bacterium; and after incubation of the bacterium and pre-activated virus for 1h at 37°C. There was a significant reduction of the infection in the times of 24h, 48h and 72h for all groups except for that where pre-incubation of the virus and bacterium did not promote any direct action on the virus that remains as infectious as the control. Recent studies have demonstrated the importance of intestinal microbiota of the progenitor influencing the development of the immune system of the offspring. To evaluate whether WpK4 would induce resistance to RVA infection via immune system modulation, the bacterium was administered daily in the water of female progenitor during the two weeks before the birth of the offspring with continuity until the 15th day of the life of the offspring. On the 9th day of the life of the offspring, the same was challenged with RVSA11 (104 FFU) and observed twice a day, for seven days postinfection. There was a higher frequency of diarrhea and three deaths in the virus control group and significantly fewer diarrhea, without any death, in the group of pregnant females pretreated with WpK4. The data highlights the probiotic protective effect of WpK4 in infection of mammalian cell lineages and mice by Rotavirus.