Morphology and immunohistochemistry of the myenteric plexus of valves constructed in the colon of rats submitted to abdominoperineal amputation and perineal colostomy

PURPOSE: To investigate immunohistochemical aspects of the myenteric plexus of valves constructed in the colon of rats to verify whether any denervation occurs both at the operative site and in those areas adjacent to the third valve. METHODS: Thirty six male Wistar rats divided into the following three groups were used: Control Group (CG); Amputated Group (AG); Amputated Group with Valves (AGWV). In AG was held in the rectum amputation and the colon was sutured to the skin elaborating the perineal colostomy. In AGWV was held in the rectum amputation. A laparotomy was performed for the manufacture of valves (seromyotomy) in the colon. After this step, the colon was sutured to the skin elaborating the perineal colostomy. The density of the neural elements in the muscular wall as marked specifically using Protein Gene Product (PGP) 9.5 and utilising the proper tools of the KS300 software for measuring the area. From these measurements, a relation and three proportions were drawn and analysed according to the mean of the averages obtained from the measured images. RESULTS: Immunoexpression of PGP 9.5 demonstrated a total absence of neural elements and myenteric plexus at the valve site. The density of the neural elements in the circular muscular layer at sites adjacent to the 3rd valve was lesser, however, was not significantly different. CONCLUSION: The immunohistochemical study of valves constructed in the colon of rats submitted to abdominoperineal amputation and perineal colostomy revealed denervation at the seromyotomy site.(AU)

Histological study of the left colon of rats after extra-mucosal seromyotomy (continent valves): evaluation of colonic emptying / Estudo histológico do cólon esquerdo de ratos após a confecção de seromiotomias extra-mucosas (válvulas continentes): avaliação do grau de esvaziamento do conteúdo colônico

PURPOSE: To elaborate an animal model with the objective of studying the continence of the biological valves surgically performed in the left colon of rats. METHODS: Thirty four rats were operated on and divided into three groups (G). G1 (sham) animals which underwent laparotomy only; G2 (perineal amputation without valves): animals which underwent amputation of the anal sphincter complex combined with a perineal colostomy; G3 (abdominoperineal amputation combined with valves): animals which underwent abdominoperineal amputation combined with three, equidistant and circumferential (360(0)), extra-mucosal seromyotomies, of the descending colon, which were sutured to create biological valves combined with perineal colostomy. Animals were euthanized in the late postoperative period and surgical valves were saved for histopathological study. RESULTS: Surgical procedure provoked intestinal dilation, as well as segmented chambers along the descending colon. Retained fecalomas between the valves and proximal to them were also noted. Six rats died of intestinal obstruction due to fecal impaction at the surgical site. The sequence of events was: stasis, obstruction, distention, perforation, peritonitis and death. Histopathology showed inflammation due to foreign body type reaction around the sutured colon causing partial concentric stenosis, capable of interfering normal mechanical activity of the distal colon. This process resulted in retardation of the intestinal transit. CONCLUSION: Extra-mucosal seromyotomies, with seromuscular suture, can be used as an operative procedure capable of causing retardation in the intestinal transit of rats.(AU)

OBJETIVO: Modelo de experimentação, com confecção de válvulas biológicas no cólon esquerdo de ratos com o objetivo de estudar o grau de continência dessas válvulas. MÉTODOS: Trinta e quatro ratos foram operados e distribuidos em três grupos: G1 (grupo simulado) submetido apenas à laparotomia, G2 (grupo amputado sem válvula) submetido à amputação do conjunto esfincteral mais colostomia perineal e G3 (grupo amputado com válvula) submetido à amputação do conjunto esfincteral, confecção de três seromiotomias extra-mucosas, eqüidistantes e circunferenciais (360(0) - válvulas biológicas), no colon descendente mais colostomia perineal. No pós-operatório tardio, os animais dos três grupos foram submetidos à eutanásia para coleta da peça cirúrgica e estudo histopatológico das válvulas. RESULTADOS: Os resultados mostraram que o procedimento culminou em dilatação intestinal, confirmada pela formação de verdadeiras câmaras de segmentação e pela presença de fecalomas retidos entre as válvulas e cranialmente a elas. Seis ratos morreram em decorrência de obstrução intestinal por impacção de fezes no local operado, na seqüência: obstrução, estase, distensão, perfuração, peritonite e morte. As alterações histopatológicas confirmaram o processo inflamatório com reação do tipo corpo estranho, no perímetro do cólon suturado, proporcionando uma estenose parcial concêntrica, levando à alteração da atividade mecânica do cólon distal, resultando no retardo do trânsito intestinal. CONCLUSÃO: As seromiotomia extramucosas, com sutura seromuscular, podem ser utilizadas como técnica operatória para se obter retardo do trânsito intestinal em ratos.(AU)