Serosal patch of the gastroesophageal junction: an experimental study in dogs

ABSTRACT

Thirty two dogs were operated on in order to evaluate the mucosal regeneration of the serosal patch at the gastroesophageal junction. The operation began with a cardiotomy involving one centimeter of the esophagus and two centimeters of the stomach, originating an elliptical serosal surface three centimeters long and one centimeter large. turned to the digestive lumen. The animals were divided into four groups of eight dogs each and named 1, 2, 3 and 4; they were sacrificed after one, two, four and eight weeks respectively. The results were evaluated by post-operative clinical aspects, macro and microscopic analysis. Post-operative morbidity was low, without signs of digestive tract obstruction. Macroscopically, the patch area at the first week became an ulcerated lesion, with a necrotic bottom; at the second and fourth weeks there was a progressive reduction of the ulcer, from its boundaries to the center, until the complete healing at the eighth week. Microscopically, the serous membrane disappeared early and it was replaced by inflamatory cells and severe neovascular formation, which fitted as a bed to the epithelial proliferation. The neo-epithelization occurred from the periphery to the center of the lesion. At the esophagus this process was completed within two weeks, with multiple layers of cells; at the stomach, within four weeks, with an unicellular epithelium. The corium, showing an inflamatory reaction at the first week, with fibrinoid necrosis and polimorphonuclear cells, changed to a fibroblastic proliferation with mononuclar cells at the second and fourth weeks and, finally, to fibrosis at the eighth week. In the animals sacrificed lately there was regeneration of the smooth muscle layer of the esophagus. At electronic microscopy, the neo-epithelium of the esophagus had all the layer which constitute the normal esophageal epithelium.

RESUMO

Trinta e dois cães foram submetidos ao tamponamento seroso da junção esofagogástrica, com o objetivo de investigar experimentalmente o processo de reparação mucosa. A operação constou de cardiotomia, interessando um centímetro do esôfago e dois centímetros do estômago. Esta secção foi obliterada pelo fundo gástrico, originando uma superfície serosa elíptica, voltada para o lúmen, com três centímetros de comprimento por um centímetro de maior largura. Os animais foram divididos em quatro grupos de oito cães cada (Grupos 1, 2, 3 e 4), sacrificados após uma, duas, quatro e oito semanas respectivamente. Os resultados foram avaliados quanto aos aspectos clínicos, pós-operatórios, e da análise macro e microscopicas dos espécimes obtidos. A evolução pós-operatória mostrou pequena morbidade, sem sinais de obstrução do trato digestivo. Ficou demonstrado à macroscopia, que a área do tamponamento exibe, na primeira semana, aspecto de lesão ulcerada, com fundo necrótico; na segunda e quarta semanas houve redução da área cruenta, até a completa cicatrização, melhor observada na oitava semana. À microscopia, a membrana serosa desapareceu precocemente, dando lugar a infiltrado inflamatório com intensa neoformação vascular, que serviu de leito para a proliferação epitelial.A neoepitelização fez-se das bordas para o centro da lesão. No esôfago, em camadas pluricelulares, completou-se em duas semanas, e no estômago, com epitélio unicelular estava completa na quarta semana.