Transforming growth factor-beta enhances connective tissue repair in perforated rat mesentery but not peritoneal macrophage chemotaxis.

The perforated rat mesentery model was used to study the effect of transforming growth factor-beta (TGF-beta) on connective tissue repair and influx of macrophages into the peritoneal cavity during such repair. Sprague-Dawley rats were laparotomized, and mesenteric wounds were made with a scalpel. A daily intraperitoneal injection of 0.5 microg TGF-beta was given for either 2 or 4 days. After 1 to 10 days, the animals received an intravenous injection of tritium-labeled thymidine before decapitation. Macrophages were collected by peritoneal washing, and the number of closed perforations was counted. Peritoneal cells were quantitated and a labeling index was determined by autoradiography. TGF-beta given for either 2 (p < 0.001) or 4 (p < 0.004) days accelerated closure of perforations on days 3 to 7 after injury. Laparotomy as such significantly increased leukocyte influx (p < 0.004), as well as macrophage-labeling index (p < 0.02). However, TGF-beta did not significantly influence either leukocyte influx or macrophage-labeling index. We concluded that TGF-beta significantly enhances connective tissue repair in this perforated rat mesentery model and that TGF-beta-induced stimulation of repair is not caused by an increased influx of macrophages into the peritoneal cavity.