STIMULATION OF PROTRACTED CONNECTIVE-TISSUE REPAIR IN NORMAL MICE BY TRANSFORMING GROWTH-FACTOR BETA(1)

The repair and contraction during connective tissue repair of mesenter ic perforations is prolonged in mice compared with rats. In the presen t study the stimulating effect of transforming growth factor beta(1) ( TGF-beta(1)) on different aspects of such repair of the mouse mesenter y was assessed. The number of closed mesenteric perforations were coun ted on different days after operation and the free peritoneal cells we re counted, the mitotic index was assessed, and actin distribution of fibroblasts around the perforation was studied with laser scanning con focal microscopy. TGF-beta(1) significantly increased the speed of clo sure and seemed to induce more actin in fibroblasts at the wound margi n. It did not significantly influence the mitotic index, but fewer fre e peritoneal cells were obtained in mice treated with TGF-beta(1). We conclude that TGF-beta(1) is a potent stimulator of connective tissue repair and contraction in mice. The different methods of closure in ra ts and mice implicate different molecular responses in wounds and furt her studies on the stimulating effect of TGF-beta(1) may indicate basi c fibroblastic cellular mechanisms that are active during contraction in connective tissue repair.