Bacterial translocation and mortality on rat model of intestinal ischemia and obstruction

Abstract Purpose: To develop an experimental model of intestinal ischemia and obstruction followed by surgical resection of the damaged segment and reestablishment of intestinal transit, looking at bacterial translocation and survival. Methods: After anesthesia, Wistar rats was subject to laparotomy, intestinal ischemia and obstruction through an ileal ligature 1.5cm of ileum cecal valve; and the mesenteric vessels that irrigate upstream of the obstruction site to approximately 7 to 10 cm were ligated. Abdominal wall was closed. Three, six or twenty-four hours after, rats were subject to enterectomy followed by an end to end anastomosis. After 24h, mesenteric lymph nodes, liver, spleen and lung tissues were surgically removed. It was studied survival rate and bacterial translocation. GraphPadPrism statistical program was used. Results: Animals with intestinal ischemia and obstruction for 3 hours survived 24 hours after enterectomy; 6hx24h: survival was 70% at 24 hours; 24hx24h: survival was 70% and 40%, before and after enterectomy, respectively. Culture of tissues showed positivity on the 6hx24h and negativity on the 3hx24h. Conclusion: The model that best approached the clinic was the one of 6x24h of ischemia and intestinal obstruction, in which it was observed bacterial translocation and low mortality rate.

Análise da diversidade da microbiota intestinal de ratos submetidos à ressecção da valva ileocecal e criação de esfíncter artificial / Analysis of the diversity of the intestinal microbiota of rats subjected to resection of the ileocecalvalve and creation of artificial sphincter

OBJETIVO: analisar através de biologia molecular a diversidade da microbiota da junção ileocecal antes e após a ressecção da válvula ileocecal e reconstrução do trânsito com e sem a criação de "neoesfíncter". MÉTODOS: Os animais foram distribuídos em dois grupos: Grupo A (n=7) com ressecção da válvula ileocecal e anastomose ileocólica término-terminal em plano único, e Grupo B (n=7) com ressecção da válvula ileocecal e anastomose ileocólica término-terminal em plano único e confecção do esfíncter artificial. Reoperados com 20 dias coletou-se novamente conteúdo intraluminar do íleo e do cólon. Das amostras coletadas, extraiu-se DNA para reação de PCR-DGGE. Os padrões de bandas eletroforéticas , gerados na reação, foram submetidos ao programa Bionumerics para análise da similaridade e da diversidade da microbiota. RESULTADOS: a diversidade da microbiota foi maior e em mais amostras do íleo do que as do cólon. O grupo com a válvula apresentou os maiores valores e variações no cólon de 2,11 a 2,93. Em três animais de cada grupo estabeleceu-se comparação da similaridade e não se assemelharam ao controle. CONCLUSÃO: a ressecção da válvula ileocecal levou à mudanças da microbiota ileal e, com a criação de novo esfíncter, as variações foram maiores.

OBJECTIVE: To analyze, through molecular biology, the diversity of the intestinal microbiota before and after resection of the ileocecal junction and reconstruction of intestinal transit with and without the creation of a neosphincter. METHODS: Fourteen Wistar rats were divided into two groups: Group A (n = 7), submitted to resection of the ileocecal valve and end-to-end, single-layer ileocolic anastomosis; and Group B (n = 7) with resection of the ileocecal valve and end-to-end, single-layer ileocolic anastomosis followed by construction of an artificial sphincter. Intraluminal contents were collected from both groups. The animals were reoperated 20 days after the first procedure, with new collection of intraluminal contents of the ileum and colon. From the samples collected, DNA was extracted for PCR-DGGE. The electrophoretic banding patterns generated in the reaction were analyzed for similarities and diversities of the microbiota. RESULTS: The diversity of microorganisms was larger and in more samples when collected from the ileum than from the colon. The group with the neosphincter showed the highest variation in the colon, from 2.11 to 2.93. In three animals from each group was established comparing the similarity and not resembled the control. CONCLUSION: ileocecal resection led to changes in ileal microbiota and, with the creation of new sphincter, the changes were even greater.

The small bowel flora in individuals with cecoileal reflux / Estudo da flora do delgado em doentes com refluxo cecoileal

BACKGROUND: The observation of cecoileal reflux to barium enema is not rare; however, its causes and consequences have not been widely investigated. Considering that ileocecal junction exerts a function as barrier to invasion of bacteria from colon to small bowel, it seems interesting to study the intestinal microflora in subjects carrying cecoileal reflux. AIMS: This study aims at evaluating the ileal flora in individuals with cecoileal reflux. METHODS: A group of 36 subjects comprising 30 females and 6 males with a mean age of 54 years was assessed. Twenty-five individuals with cecoileal reflux and 11 without cecoileal reflux were submitted to small intestine contamination evaluation through the breath test with lactulose-H2 and measurement of the orocecal transit time by means of alternate current biosusceptometry. Small intestine bacterial overgrowth was characterized by orocecal transit time-H2 shortening. RESULTS: Comparison of basal H2, orocecal transit time-H2 and orocecal transit time-alternate current biosusceptometry measurements did not statistically differ between the groups with and without cecoileal reflux. Orocecal transit time-H2 was significantly smaller than orocecal transit time-alternate current biosusceptometry, particularly in individuals with cecoileal reflux. A significant correlation between the two methods was observed only in relation to control, not existing in relation to cecoileal reflux group. CONCLUSIONS: Smaller orocecal transit time-H2 and the loss of correlation with orocecal transit time-alternate current biosusceptometry observed in the individuals with cecoileal reflux suggest a differentiated behavior for such group relative to control, which could be associated with small intestine bacterial overgrowth.

RACIONAL: Fato de observação não rara, é o encontro de refluxo cecoileal durante realização de enema opaco. As causas e conseqüências deste achado têm sido pouco estudadas. OBJETIVOS: Sabendo que a junção ileocecal exerce função de barreira e proteção contra a invasão do delgado pela flora colônica, realizou-se o presente estudo com a finalidade de investigar se existe contaminação ileal em indivíduos com refluxo cecoileal ao enema opaco. MÉTODOS: Investigaram-se 36 indivíduos, 30 mulheres e 6 homens, idade média de 54 anos, 25 com e 11 com ausência refluxo cecoileal. Todos submetidos a pesquisa de contaminação bacteriana do delgado por intermédio de teste respiratório com lactulose-H2 e a determinação do tempo de trânsito orocecal por meio de biossusceptometria de corrente alternada. A caracterização da contaminação do delgado foi baseada no encurtamento do tempo de trânsito orocecal medido pelo teste da lactulose-H2. RESULTADOS: A comparação dos valores basais do H2, do tempo de trânsito orocecal-H2 e tempo de trânsito orocecal-biossusceptometria de corrente alternada não diferiram estatisticamente entre os grupos com e sem refluxo cecoileal. Quando comparados os tempo de trânsito orocecal-H2 e tempo de trânsito orocecal-biossusceptometria, foi observado aumento de tendência de redução do primeiro em relação ao último nos grupos com refluxo cecoileal e correlação significante entre os dois métodos apenas no grupo-controle, inexistindo nos com refluxo cecoileal. CONCLUSÃO: Encurtamento do tempo de trânsito orocecal-H2 e sua perda de correlação com o tempo de trânsito orocecal-biossusceptometria observado em indivíduos com refluxo cecoileal, sugerem comportamento diferenciado deste grupo em relação ao grupo-controle. Possível explicação para as diferenças registradas entre os grupos, seria a presença de flora anômala nos indivíduos com refluxo cecoileal.