Rat models of high risk colorectal anastomoses 1.

Valter Alvarenga Junior,Pedro Teixeira Da Silva,Christina Maeda Takiya,Olavo Borges Franco,Alberto Schanaider,José Eduardo Ferreira Manso,Mariana Menegat Dias Cordeiro,José Marcus Raso Eulálio,Wagner Baetas-Da-Cruz,Heitor Siffert Pereira De Souza,Amabile Marran Carra,Marcia Rolim,Edna Delabio Ferraz,Manoel Luiz Ferreira,Paulo César Silva

doi:10.1590/s0102-865020180100000006

Valter Alvarenga Junior, Pedro Teixeira Da Silva + Show 13 more

Open Access

https://doi.org/10.1590/s0102-865020180100000006

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Abstract

To evaluate the most frequent surgical techniques of high-risk colorectal anastomoses in rats. Wistar rats were enrolled in three different models comprising inflammatory (TNBS enema), vascular (portal vein occlusion) or obstructive (a non-ischemic constricting ring) mechanisms associated with colonic anastomosis that had accomplished after these former lesions. Histological analyses (Hematoxylin and eosin and Picrosirius red) were performed. All anastomoses techniques were associated with risk factors and had complications, mainly anastomotic leakage. In Study 1, the use of a pharmacological agent, trinitrobenzene sulfonic acid (TNBS) mimicked an inflammatory bowel disease such as Crohn's disease with 50% of anastomosis leakage, the higher percentage among all models tested. In Study 2, after portal ischemia followed by reperfusion it was observed a dense neutrophil infiltrate in the midst of necrotic tissue and fibrin at the anastomotic site and 5 days after the anastomosis, no collagen was produced. In Study 3, 5 days after the mechanical obstruction some denuded areas of epithelium with marked oedema of mucosa and submucosa were seen, at the anastomotic site and anastomosis group showed some reduction of collagen density when compared with Control/Sham group. All the experimental surgical techniques tested in rats were associated with high-risk colorectal anastomoses and were useful to study colonic anastomotic healing and intestinal leakage.

Highlights

Treatment of high-risk colorectal anastomosis associated with intestinal leakage is still a challenge
The best surgical management to deal with acute left-colon inflammation, ischemia with peritonitis or obstruction is still controversial
In the Model 2, 20% of the rats of the portal occlusion followed by anastomosis group had suture dehiscence within the first 5 post- operative days

Summary

Introduction

Treatment of high-risk colorectal anastomosis associated with intestinal leakage is still a challenge. The impact of anastomotic dehiscence on patient morbidity and quality of life is devastating, even when it is detected within the limit of 60 minutes, since such situation usually leads to fecal peritonitis and uncontrollable sepsis[1]. Except for abdominal impairment due to inadequate surgical technique, inflammation is the main substrate of dehiscence in colonic anastomosis. Other pathophysiological mechanisms are frequently associated, including vascular or obstructive causes[2]. The best surgical management to deal with acute left-colon inflammation, ischemia with peritonitis or obstruction is still controversial. Others may advocate resection and direct anastomosis. To deepen the studies with experimental models of highrisk anastomoses can improve the knowledge and help surgeons to make the best decision

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