PIBID/QUÍMICA-UECE: Jogos Didáticos para o Ensino de Química

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Construction of a skin substitute composed of porcine collagen matrix populated with human dermal fibroblasts and keratinocytes: histological evaluation

INTRODUÇÃO: O uso de enxertos autólogos é limitado pela extensão da área doadora e pelo estado clínico dos pacientes, no caso de lesões extensas. Alotransplantes coletados de cadáveres ou voluntários são rejeitados após uma ou duas semanas, servindo apenas como cobertura temporária para essas lesões. O tratamento de grandes lesões cutâneas com tegumento autólogo reconstruído constitui alternativa atraente, já que, a partir de um pequeno fragmento de pele do paciente, pode-se obter culturas de células que se multiplicam rapidamente e podem ser criopreservadas, permitindo, assim, sua utilização em novos tratamentos por tempo indeterminado. Este estudo pretendeu avaliar o comportamento histológico de queratinócitos e fibroblastos humanos cultivados sobre uma matriz de colágeno porcino derivada da submucosa intestinal. MÉTODO: Células da epiderme e derme humana foram cultivadas separadamente e semeadas sobre matriz de colágeno porcino, onde permaneceram em ambiente controlado por 21 dias, antes de serem submetidas a análise histológica. RESULTADOS: Observou-se que os fibroblastos invadem e colonizam a matriz de colágeno, enquanto os queratinócitos se organizam de forma laminar e estratificada sobre a superfície em que foram semeados. CONCLUSÕES: A utilização da matriz de colágeno porcino como carreador de células da pele humana é possível e a organização dessas células se assemelha à arquitetura da pele humana

Antimicrobial activity against oral pathogens and immunomodulatory effects and toxicity of geopropolis produced by the stingless bee Melipona fasciculata Smith

<p>Abstract</p> <p>Background</p> <p>Native bees of the tribe Meliponini produce a distinct kind of propolis called geopropolis. Although many pharmacological activities of propolis have already been demonstrated, little is known about geopropolis, particularly regarding its antimicrobial activity against oral pathogens. The present study aimed at investigating the antimicrobial activity of <it>M. fasciculata </it>geopropolis against oral pathogens, its effects on <it>S. mutans </it>biofilms, and the chemical contents of the extracts. A gel prepared with a geopropolis extract was also analyzed for its activity on <it>S. mutans </it>and its immunotoxicological potential.</p> <p>Methods</p> <p>Antimicrobial activities of three hydroalcoholic extracts (HAEs) of geopropolis, and hexane and chloroform fractions of one extract, were evaluated using the agar diffusion method and the broth dilution technique. Ethanol (70%, v/v) and chlorhexidine (0.12%, w/w) were used as negative and positive controls, respectively. Total phenol and flavonoid concentrations were assayed by spectrophotometry. Immunotoxicity was evaluated in mice by topical application in the oral cavity followed by quantification of biochemical and immunological parameters, and macro-microscopic analysis of animal organs.</p> <p>Results</p> <p>Two extracts, HAE-2 and HAE-3, showed inhibition zones ranging from 9 to 13 mm in diameter for <it>S. mutans </it>and <it>C. albicans</it>, but presented no activity against <it>L</it>. <it>acidophilus</it>. The MBCs for HAE-2 and HAE-3 against <it>S. mutans </it>were 6.25 mg/mL and 12.5 mg/mL, respectively. HAE-2 was fractionated, and its chloroform fraction had an MBC of 14.57 mg/mL. HAE-2 also exhibited bactericidal effects on <it>S. mutans </it>biofilms after 3 h of treatment. Significant differences (p < 0.05) in total phenol and flavonoid concentrations were observed among the samples. Signs toxic effects were not observed after application of the geopropolis-based gel, but an increase in the production of IL-4 and IL-10, anti-inflammatory cytokines, was detected.</p> <p>Conclusions</p> <p>In summary, geopropolis produced by <it>M. fasciculata </it>can exert antimicrobial action against <it>S. mutans </it>and <it>C. albicans</it>, with significant inhibitory activity against <it>S. mutans </it>biofilms. The extract with the highest flavonoid concentration, HAE-2, presented the highest antimicrobial activity. In addition, a geopropolis-based gel is not toxic in an animal model and displays anti-inflammatory effect.</p