Evaluation of mesalazine polymeric conjugate in the treatment of actinic proctitis in rats

ABSTRACT Purpose: The present study aimed at testing a new formulation of mesalazine linked to chondroitin sulfate and its components alone in the treatment of actinic proctitis in rats. Methods: Forty-seven female Wistar rats were submitted to pelvic radiation and divided into eight groups: control A, mesalazine A, chondroitin A, and conjugate A, gavage of the according substance two weeks after irradiation and sacrifice three weeks after oral treatment; control C, mesalazine C, chondroitin C, and conjugate C, sacrifice six weeks after oral treatment. The rectum was submitted to histological characterization for each of the findings: inflammatory infiltrate, epithelial degeneration, mucosal necrosis, and fibrosis. Results: The inflammatory infiltrate was more intense in chondroitin A, mesalazine A, and conjugate C. The collagen deposition was less intense in chondroitin A, and mesalazine A, and more intense in control C. Conclusions: Mesalazine and chondroitin alone were efficacious in inducing a delayed inflammatory response, hence reducing the late fibrosis. The conjugate was able to induce an ever more delayed inflammatory response.

Development of a new model of actinic enteritis in rats using a cobalt-60 open source and a protection device as a collimator

Purpose: To describe a new model of actinic enteritis that does not use radiotherapy machines. Methods: Sixteen Wistar rats were divided into four groups, consisting of four animals each: control (group A), two weeks after irradiation (group B), five weeks after irradiation (group C) and eight weeks after irradiation (group D). Animals were given a 10Gy radiation from a Cobalt-60 natural source in a nuclear technology research center. Protections of the surrounding tissues were obtained through the usage of plumb devices with a hole in the center, which served as a collimator. We obtained irradiated and non-irradiated colons from each animal. Results: In group B we found an important inflammatory response in the irradiated colon, which appeared in a reduced way in group C and was minimal in group D, in which we found a relevant collagen submucosal deposition/fibrosis. In all groups, the non-irradiated colon had a lower pathological damage in comparison with the irradiated colon. Conclusion: We thus described an efficient and feasible technique for obtaining an animal model of actinic enteritis.(AU)

Radiação gama e nitrito de sódio na composição química e textura de mortadelas / Gamma radiation and sodium nitrite on chemical composition and textural properties of mortadellas

Um delineamento composto central rotacional (DCCR) foi conduzido para estudar os efeitos simultâneos da adição de nitrito (43,6; 150; 256,4; e 300 ppm) e de doses de radiação gama (2,9; 10; 17,1; e 20 kGy) nos atributos de textura e parâmetros físico-químicos de mortadelas. O pH, composição química e adesividade das mortadelas não foram afetados por nenhuma das variáveis estudadas, enquanto a dureza e a mastigabilidade foram influenciados pela aplicação da radiação gama. Modelos de regressão significativos (P 0,05) foram estabelecidos para a atividade de água, coesividade e flexibilidade das amostras. Estes modelos indicam que os efeitos da irradiação gama sobre estes parâmetros é dependente do nível de nitrito adicionado, sendo o comportamento diferente para amostras com níveis de adição menores que 150 ppm de nitrito daquelas com níveis de adição maiores.(AU)

A central composite rotational design (DCCR) was conducted to study simultaneously the effects of nitrite additions (43.6, 150, 256.4 and 300 ppm) and gamma irradiation (2.9, 10, 17.1 and 20 kGy) in texture attributes and physicochemical parameters of bologna-type sausages. The pH, chemical composition and adhesiveness were not affected by any of the variables studied, while hardness and chewiness were influenced by gamma irradiation. Significant models of regression (P 0.05) were established for water activity, cohesiveness and springiness. These models indicate that the effects of gamma irradiation on these parameters are dependent on the level of nitrite added. The effects of irradiation in sausages with less than 150 ppm nitrite were distinct from samples with higher levels of addition.(AU)