ABSTRACT
Background: Between 40,000-70,000 people die yearly of rabies, an incurable disease. Besides post-bite vaccination, no treatment is available for it. Methods: First, virus dilution for antiviral effects in mice was determined. Then, animals were treated as follows: control (NaCl 250 µL/animal/day); bufotenine (0.63, 1.05 and 2.1 mg in 250 µL of NaCl/animal/day); rabies (10-6,82CVS dilution); and test (10-6,82 CVS dilution and bufotenine, in the above-mentioned doses). Animals were observed daily for 21 days or until the 3rd stage of rabies infection. Twitch-tension and liposome studies were applied to understand the possible interaction of bufotenine with receptors, particularly acetylcholine. Results: Bufotenine was able to increase the survival rate of intracerebrally virus-infected mice from 15 to 40%. Bufotenine did not seem to interfere with the acetylcholine response in the skeletal muscle, indicating that its mechanism of action is not blocking the virus entrance due to nAChR antagonism. By analyzing liposomes, we could observe that bufotenine did not passively penetrates cell membranes, indicating the necessity of complementary structures to cell penetration. Conclusions: Bufotenine is a promising candidate for drug development. After further chemical modification, it might be possible to dissociate minor side effects, increase efficiency, efficacy and pharmacokinetics, yielding a true anti-rabies drug.
ABSTRACT
Background: Between 40,000-70,000 people die yearly of rabies, an incurable disease. Besides post-bite vaccination, no treatment is available for it. Methods: First, virus dilution for antiviral effects in mice was determined. Then, animals were treated as follows: control (NaCl 250 µL/animal/day); bufotenine (0.63, 1.05 and 2.1 mg in 250 µL of NaCl/animal/day); rabies (10-6,82CVS dilution); and test (10-6,82 CVS dilution and bufotenine, in the above-mentioned doses). Animals were observed daily for 21 days or until the 3rd stage of rabies infection. Twitch-tension and liposome studies were applied to understand the possible interaction of bufotenine with receptors, particularly acetylcholine. Results: Bufotenine was able to increase the survival rate of intracerebrally virus-infected mice from 15 to 40%. Bufotenine did not seem to interfere with the acetylcholine response in the skeletal muscle, indicating that its mechanism of action is not blocking the virus entrance due to nAChR antagonism. By analyzing liposomes, we could observe that bufotenine did not passively penetrates cell membranes, indicating the necessity of complementary structures to cell penetration. Conclusions: Bufotenine is a promising candidate for drug development. After further chemical modification, it might be possible to dissociate minor side effects, increase efficiency, efficacy and pharmacokinetics, yielding a true anti-rabies drug.
ABSTRACT
Os modelos experimentais desenvolvidos através da seleção genética bi-direcional são ferramentas importantes para o estudo da genética de caracteres multifatoriais, permitindo concentrar os genes de interesse ao caráter fenotípico estudado. A seleção III foi desenvolvida por meio da resposta secundária a antígenos flagelar de Salmonella entérica para a alta (High) ou baixa (Low) produção de anticorpos. A produção de anticorpos deriva de vários processos partindo da ativação do sistema imune adquirido, compartilhando muitos mecanismos moleculares submetidos a controles genéticos independentes. Assim procurou-se avaliar se os genes selecionados para este fenótipo poderiam interferir em diferentes parâmetros como a resposta inflamatória aguda induzida pela inoculação de Biogel, ativação macrofágica (produção de NO e H2O2), produção de citocinas e capacidade de regeneração tissular nas linhagens. O estimulo inflamatório induzido pelo Biogel foi semelhante nos animais das linhagens High e Low da seleção III. No entanto, os camundongos machos obtiveram quantidades maiores de neutrófilos no infiltrado celular após estímulo com Biogel que as fêmeas; 90% das células do exsudato apresentaram o fenótipo CD11b+/ GR1+. A inoculação do tioglicolato (in vivo) juntamente com o estimulo do LPS (in vitro) induziram maior ativação macrofágica com liberação de óxido nítrico e peróxido de hidrogênio nos camundongos machos da linhagem High; enquanto que o estimulo de ConA (in vivo) juntamente com o LPS (in vitro) induziram maior ativação macrofágica nos animais fêmeas da linhagem Low. Concentrações elevadas das citocinas pró inflamatórias como a IL-1 , IL- 6, IFN- e IL-12 e TNF- foram observadas em ambas as linhagens após o tratamento com ConA e LPS. Por fim, o processo de regeneração tissular na orelha não foi observado nos animais de ambas as linhagens.
