Evaluation of the healing of surgically created small colon serosal lesions in horses, treated by homologous pericardium implantation: An experimental study

The healing of serosal lesions created in the small colon of horses and treated by homologous pericardium implantation was evaluated. A standing left flank laparotomy was performed in 6 horses. The small colon was partially exposed, and a defect measuring 2 × 2 cm was created in the serosa between the mesenteric border and the anti-mesenteric taenia. A square piece of homologous pericardium preserved in a 98% glycerin solution was rehydrated, dried, and sutured over the defect. Recovery of the animals was uneventful, with no signs of abdominal discomfort and no significant changes in physiologic variables, intestinal motility, behavior, appetite, or defecation pattern. The same was true for the erythrogram (packed cell volume, red cell count, and hemoglobin concentration), leukogram, and plasma fibrinogen values. The animals were reoperated on through the ventral midline approach after 4, 5, 6, 7, 8, and 35 weeks, respectively, and the implants were inspected visually and collected for microscopic study. No adhesions were found. Initially, there was a rim of fibrotic tissue covering the suture line, which regressed over time and was no longer evident after 7 weeks. From that moment on, progressive integration of the implant to the intestinal serosa was observed. Histopathologic examination revealed a late healing process, with infiltration of mononuclear cells, fibroblasts, neovascularization, and mature collagen fibers, which increased in intensity up to 6 weeks and then progressively regressed. At 5 weeks, it was already difficult to distinguish between the implant and the intestinal serosa. Our conclusion was that homologous pericardium implants have good acceptance in intestinal serosal lesions in horses and offer a good perspective for clinical application.