Gastrectomy in the rat using two modifications of esophagojejunal anastomosis. general status, local histological changes and relationships to bone density.
Gastrectomy (GX) was carried out in the male rat according to the Longmire and the Roux-en-Y procedure. The focus of the postoperative investigations was to evaluate the influence of post-GX morphological changes occurring at the site of two types of end-to-end esophagojejunal anastomosis (with and without invagination), in particular food intake, body weight gain, food efficiency, hematocrit and bone density. GX failed to alter food intake, fasting blood glucose, alpha-amino nitrogen, or free fatty acids, but led to uniformly decreased body weight, food efficiency and serum gastrin, and increased serum osteocalcin, indicating high turnover osteopenia. However, irrespective of the type of (digestive tract) reconstruction (Longmire or Roux-en-Y), the invagination anastomosis was associated with lower mortality, fewer complications, less early postoperative weight loss, less intensive tissue changes at the anastomotic site, and improvement of bone density and hematocrit. Bivariate and multivariate regression analysis revealed that bone density was negatively influenced by epithelial hyperplasia of the anastomotic tissue, while hematocrit was positively influenced by bone density. In contrast, food intake appeared to have no influence. It was concluded that (1) the histological status of the esophagointestinal anastomosis varies depending on the surgical technique applied and (2) the type of anatomical reconstruction of the digestive tract (Longmire vs. Roux-en-Y) and food intake may be of minor importance for the bone and hematological status of GX rats. Future investigations are justified to clarify whether esophagojejunal proinflammatory tissue factors may contribute to the GX-mediated damage of bone mineral and bone marrow, thereby leading to low body weight.