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

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.

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.

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

Abstract 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.

CagA-positive Helicobacter pylori strain containing three EPIYA C phosphorylation sites produces increase of G cell and decrease of D cell in experimentally infected gerbils (Meriones unguiculatus).

PURPOSE: Human infection by Helicobacter pylori is associated with an increase in the number of gastrin-producing G cells and a concomitant decrease of somatostatin-producing D cells. However, to our knowledge, changes in G and D cell numbers in response to infection with H. pylori CagA-positive strains containing different number of EPIYA-C phosphorylation sites have not been analyzed to date. Therefore, the aim of this study was to perform a quantitative analysis of the number of G and D cells in Mongolian gerbils challenged with H. pylori strains with different numbers of EPIYA-C motifs. MATERIALS AND METHODS: Mongolian gerbils were inoculated with isogenic H. pylori strains containing one to three phosphorylation sites. Mucosal fragments were evaluated by morphometry and immunohistochemistry using primary polyclonal rabbit anti-gastrin and anti-somatostatin antibodies. Positive cells were counted using an image analyzer. RESULTS: Forty-five days after infection, there was a decrease in the number of D cells and an increase in the G/D cell ratio in the group with three EPIYA-C. Six months after infection, there was a progressive and significant increase in the number of G cells and in the G/D cell ratio, with a concomitant decrease in the number of D cells, especially in the three EPIYA-C group. CONCLUSIONS: CagA-positive H. pylori strains containing a large number of EPIYA-C phosphorylation sites induce a decrease in D cell number and an increase in G cell number and G/D ratio, which were correlated with the number of inflammatory cells of the lamina propria.

Use of the amniotic membrane to cover the peritoneal cavity in the reconstruction of the abdominal wall with polypropylene mesh in rats.

OBJECTIVE: to evaluate the efficacy of the amniotic membrane used with polypropylene mesh against the formation of adhesions and its influence on healing. METHODS: twenty five female Wistar rats were anesthetized for creating a parietal defect in the anterior abdominal wall. Its correction was made with polypropylene mesh alone and associated with amniotic membrane. In the control group (n=11), the screen was inserted alone. In group A (n=7) we interposed the amniotic membrane between the screen and the abdominal wall. In group B, the amniotic membrane was placed on the mesh, covering it. After seven days, the animals were euthanized for macroscopic and microscopic evaluation of healing. RESULTS: adhesions were observed in all animals except one in the control group. Severe inflammation was observed in all animals in groups A and B and in three of the control group, with significant difference between them (A and B with p=0.01). Pronounced angiogenic activity was noted in one animal in the control group, six in group A and four in group B, with a significant difference between the control group and group A (p=0.002) and group B (p=0.05). The scar collagen was predominantly mature, except in five animals of the control group, with significant difference between the control group and group A (p=0.05) and group B (p=0.05). CONCLUSION: The amniotic membrane did not alter the formation of adhesions in the first postoperative week. There were also pronounced inflammation, high angiogenic activity and predominance of mature collagen fibers, regardless of the anatomical plane that it was inserted in.

Use of the amniotic membrane to cover the peritoneal cavity in the reconstruction of the abdominal wall with polypropylene mesh in rats / Uso da membrana amniótica como cobertura da cavidade abdominal na reconstrução da parede com tela de polipropileno em ratos

OBJECTIVE: To evaluate the efficacy of the amniotic membrane used with polypropylene mesh against the formation of adhesions and its influence on healing. METHODS: twenty five female Wistar rats were anesthetized for creating a parietal defect in the anterior abdominal wall. Its correction was made with polypropylene mesh alone and associated with amniotic membrane. In the control group (n=11), the screen was inserted alone. In group A (n=7) we interposed the amniotic membrane between the screen and the abdominal wall. In group B, the amniotic membrane was placed on the mesh, covering it. After seven days, the animals were euthanized for macroscopic and microscopic evaluation of healing. RESULTS: adhesions were observed in all animals except one in the control group. Severe inflammation was observed in all animals in groups A and B and in three of the control group, with significant difference between them (A and B with p=0.01). Pronounced angiogenic activity was noted in one animal in the control group, six in group A and four in group B, with a significant difference between the control group and group A (p=0.002) and group B (p=0.05). The scar collagen was predominantly mature, except in five animals of the control group, with significant difference between the control group and group A (p=0.05) and group B (p=0.05). CONCLUSION: The amniotic membrane did not alter the formation of adhesions in the first postoperative week. There were also pronounced inflammation, high angiogenic activity and predominance of mature collagen fibers, regardless of the anatomical plane that it was inserted in.

OBJETIVO: Avaliar a eficácia da membrana amniótica usada com tela de polipropileno contra a formação de aderências e sua influência na cicatrização. MÉTODOS: vinte e cinco ratas Wistar foram anestesiadas para criação de um defeito parietal na parede abdominal anterior. Sua correção foi feita com tela de polipropileno isolada e associada à membrana amniótica. No grupo Controle (n=11), a tela foi inserida isoladamente intra abdominal. No grupo A (n=7), interpôs-se a membrana amniótica entre a tela e a parede abdominal. No grupo B, a membrana amniótica foi colocada sobre a tela, recobrindo-a. Após sete dias, os animais foram eutanasiados para avaliação macroscópica e microscópica da cicatrização. RESULTADOS: aderências foram observadas em todos os animais, exceto em um do grupo Controle. Inflamação acentuada foi observada em todos os animais dos grupos A e B e em três do grupo Controle, com diferença significativa entre eles (A e B com p=0,01). Acentuada atividade angiogênica foi notada em um animal do grupo Controle, seis do grupo A e quatro do grupo B, com diferença significativa entre o grupo Controle e os grupos A (p=0,002) e B (p=0,05). O colágeno cicatricial foi predominantemente maduro, exceto em cinco animais do grupo Controle, com diferença significativa entre o grupo Controle e os grupos A (p=0,05) e B (p=0,05). CONCLUSÃO: a presença da membrana amniótica não alterou a formação de aderências na primeira semana de pós-operatório. Associou-se à inflamação acentuada, elevada atividade angiogênica e predomínio de fibras colágenas maduras, independente do plano anatômico em que foi inserida.

Use of alloplastic meshes in abdominal wounds of rats with induced peritonitis.

BACKGROUND: The use of alloplastic meshes has been historically contra-indicated in patients with infection. AIM: To evaluate the use of polypropylene meshes in the treatment of abdominal wall defects in rats with peritonitis. METHODS: Twenty Wistar female rats were divided into two groups: induction of peritonitis (test group) and without peritonitis (control group). An abdominal wall defect was created in all animals, and polypropylene mesh was applied. The evaluation of the tensile strength of the mesh was carried out using tensiometer and microscopic analysis of the healing area was done. RESULTS: More adhesion of the mesh to the rat abdominal wall was observed in test group. The histopathological analyses showed prevalence of moderate to accentuated granulation tissue in both groups, without significant differences. CONCLUSION: The use of the mesh coverage on abdominal wall defects of rats with induced peritonitis did not show worse results than its use in healthy animals, nor was its integration to the resident tissue any worse.

Use of alloplastic meshes in abdominal wounds of rats with induced peritonitis / Uso de telas inorganicas em feridas abdominais de ratos com peritonite induzida

Background : The use of alloplastic meshes has been historically contra-indicated in patients with infection. Aim : To evaluate the use of polypropylene meshes in the treatment of abdominal wall defects in rats with peritonitis. Methods : Twenty Wistar female rats were divided into two groups: induction of peritonitis (test group) and without peritonitis (control group). An abdominal wall defect was created in all animals, and polypropylene mesh was applied. The evaluation of the tensile strength of the mesh was carried out using tensiometer and microscopic analysis of the healing area was done. Results : More adhesion of the mesh to the rat abdominal wall was observed in test group. The histopathological analyses showed prevalence of moderate to accentuated granulation tissue in both groups, without significant differences. Conclusion : The use of the mesh coverage on abdominal wall defects of rats with induced peritonitis did not show worse results than its use in healthy animals, nor was its integration to the resident tissue any worse. .

Racional: O uso de telas inorgânicas historicamente é contra-indicado em paciente com infecções. Objetivo : Avaliar o comportamento e cicatrização de paredes abdominais com uso de telas de polipropileno após infecções intra-cavitárias. Método : Foram estudadas 20 ratas Wistar aleatoriamente divididas nos grupos Estudo (com peritonite) e Controle (sem peritonite). Um defeito na parede abdominal foi criado em todos os animais, onde foi aplicada tela de polipropileno. Foi feita avaliação da força de tensão com uso de tensiômetro, além de análise histológica da área cicatricial. Resultados : Observou-se maior adesividade da tela às paredes dos animais do grupo Estudo quando comparado ao grupo Controle. A análise histopatológica mostrou prevalência de tecido de granulação de acentuado à moderado em ambos os grupos, sem diferença significativa. Conclusão : O uso de telas inorgânicas nos defeitos da parede abdominal em ratos com peritonite induzida não mostrou resultado pior do que aquele obtido de animais sem infecção, tanto em relação à sua integração quanto ao tecido cicatricial no defeito da parede abdominal. .

Effect of peritoneal cavity lavage with 0.9% and 3.0% saline solution in the lung and spleen of gerbils with induced peritonitis.

BACKGROUND: Peritoneal cavity lavage is used widely in the treatment of peritonitis. Nonetheless, some studies question its rationale and prove it to be deleterious to the mesothelium. The present study aims to determine whether 0.9% and 3.0% saline lavage of the peritoneal cavity have an effect on the early systemic inflammatory response, namely, in the lung injury and splenic cellularity of gerbils with induced peritonitis. METHODS: Thirty-four male gerbils were divided into four groups: Control (n=9), submitted to laparotomy at time zero, re-laparotomy after 2 h, and sacrificed after a total of 6 h from start; untreated (n=8), submitted to peritonitis induction through cecal ligation and puncture (CLP) at time zero, re-laparotomy intended for drying of abdominal cavity and resection of the ischemic cecum after 2 h, and sacrifice after a total of 6 h from start; saline (n=8), submitted to peritonitis induction through CLP at time zero, re-laparotomy intended for warm 0.9% saline lavage of the abdominal cavity and resection of the ischemic cecum after 2 h, and sacrificed after a total of 6 h from start; and hypertonic (n=9), submitted to peritonitis induction through CLP at time zero, re-laparotomy intended for warm hypertonic saline (3.0%) lavage of the abdominal cavity and resection of the ischemic cecum after 2 h, and sacrificed after a total of 6 h from start. After sacrifice, we collected the left lung and the spleen for morphometric analysis. RESULTS: In the both the saline and hypertonic groups, there was significant decrease in the mean nuclei count in the lungs, compared with the untreated group (p<0.01). There was no difference in terms of nuclei count in the spleen among groups (p>0.05). CONCLUSIONS: The present study demonstrated that the peritoneal lavage with large volumes of warm 0.9% and 3.0% saline has a beneficial effect on the early systemic inflammatory response in infected animals, modulating and reducing the lung injury but having no effect on splenic cell count.

Cicatrização do cólon após mucosectomia mecânica e sutura evertente em ratos / Healing of colon after mechanic mucosectomy and evertent suture in rats

A mucosectomia é utilizada durante a confecção de reservatórios ileais nas proctocolectomias por doença inflamatória intestinal. Entretanto, tem-se relatado aumento da incidência de obstruções intestinais em pacientes submetidos ao procedimento, sendo que o contato de uma grande área de submucosa poderia ser responsável pela ocorrência de estenoses, além de poder relacionar-se com aumento da pressão de ruptura desses segmentos. Com o objetivo de avaliar as alterações macroscópicas após a mucosectomia e a pressão de ruptura desses segmentos, foram estudados 16 ratos Holtzman distribuídos em dois grupos: A (n=8), anastomose colo-cólica em plano único extramucoso invertente com pontos separados de fio absorvível e B (n=8), mucosectomia e anastomose colocólica em plano único evertente com pontos separados de fio absorvível. No terceiro dia pós-operatório, foram estudadas as alterações macroscópicas e a pressão de ruptura dos segmentos colônicos contendo as anastomoses. Os resultados obtidos mostraram aumento na incidência e intensidade das aderências peritoneais nos animais do grupo B (p=0,01), incidência de 100% de estenoses das anastomoses, sem que ocorresse qualquer estenose no grupo A (p=0,01) e aumento não significativo na pressão de ruptura das anastomoses no grupo B (4,3 ± 2,4 mmHg vs. 10,5 ± 8,2 mmHg). Concluindo, a mucosectomia aumentou a reação inflamatória tecidual, sendo causa não só de aumento na pressão de ruptura como na incidência de estenoses de anastomoses colônicas de ratos.

The mucosectomy is used during the making of the ileal pouch in proctocolectomy due to inflammatory bowel disease. However, there are reports of increased incidence of intestinal obstructions in patients undergoing the procedure, when the contact of a large submucosal area could be responsible for the stenosis, and can relate to the increase of burst pressure of these segments. To evaluate the macroscopic alterations after the mucosectomy and the burst pressure of these segments, 16 Holtzman rats were studied divided into two groups: A (n = 8), colo-colic anastomosis in extra mucosal single invertent plan with separate absorbable sutures and B (n = 8), mucosectomy and colo-colic anastomosis in a single evertent plane with separate absorbable sutures. On the third post-operatory day the macroscopic alterations and burst pressure of the colony segments containing the anastomosis were studied. The found results showed increase in the incidence and intensity of peritoneal adherences in the animals of group B (p=0,01), incidence of 100% of the anastomosis steanosis, with no occurrence of stenosis in the group A (p=0,01), and no significant increase in the burst pressure in the group B (4,3 ± 2,4 mmHg vs. 10,5 ±8,2 mmHg). Conclusion : the mucosectomy increased the tissue inflammatory reaction, giving cause to the increase of the burst pressure as well as the incidence of colonic anastomosis steanaosis in rats.