Anti-TGFβ1 antibody for modulation of expression of endogenous transforming growth factor beta 1 to prevent fibrosis after plastic surgery in rats

The cytokine transforming growth factor beta 1 (TGFβ1) substantially influences synthesis of extracellular matrix, fibrosis, and neoangiogenesis during wound healing in a dose dependent manner. We carried out experiments in rats to measure the degree of reduction of disorders of wound healing and fibrosis produced by inhibition of endogenous TGFβ1 by polyclonal antibodies (poAB). A free myocutaneous gracilis flap was transplanted from the groin to the neck region in 30 Wistar rats (300–450 g body weight). In 15 animals intraoperatively and daily from days 3 to 7 postoperatively, 1 μg anti-TGFβ1 poAB in 500 μl of phosphate buffered saline (PBS) were injected into the neck region. Fifteen animals served as controls. On postoperative days 3, 4, 5, 7, 14, and 28 the expression of endogenous TGFβ1 in cytoplasm was analysed by immunohistochemistry (ABC-POX; AEC), in situ hybridisation of TGFβ1-mRNA, and Sirus Red staining of collagen matrix; it was quantified using labelling indices. Neutralisation of the TGFβ1 activity by specific poAB resulted in inhibition of the cytoplasmatic expression compared with untreated animals. In the transition area between grafted tissue and graft bed, a significant reduction of TGFβ1 expression (mean (S.D.) 34.7 (6.5)) was found from day 5 in the group treated with anti-TGFβ1 poAB compared with the control group (mean (S.D.) 48.1 (6.6)) (P<0.03). Up to day 14 the endogenous expression of TGFβ1 (mean (S.D.) 30.0 (2.8)) was reduced after the application of anti-TGFβ1 poAB compared with the control group (mean (S.D.) 44.0 (12.3)). Sirus Red staining indicated a more complex packed structure and generally more prominent collagen types I–IV fibres in untreated animals than in animals that were given anti-TGFβ1 poAB. Expression of TGFβ-mRNA by in situ hybridisation was reduced in fibroblasts in animals that were given anti-TGFβ1 poAB. The results indicate that anti-TGFβ1 might improve the healing of free flaps in the graft beds of patients who are prone to excessive fibrosis.