Effect Of Transforming Growth Factor-Beta 1 On The Expression Of Peroxisome Proliferator-Activated Receptor Beta And Scar Formation In Rabbit Ears

Numerous studies have investigated the role of transforming growth factor (TGF)-beta 1 in wound healing and hypertrophic scarring; however, the precise pathological mechanisms of TGF-beta 1 in scar constitution remain unclear. In the present study, we arranged a wound healing model in rabbit ears, and then treated the wounds weekly with TGF-beta 1 to investigate the exact role of TGF-beta 1 in the hypertrophic scar. In the control group, wounds were conducted with the same dosage of saline. Changes in the histopathological characteristics of scars were examined, as well as changes in the expression of TGF-beta 1, peroxisome proliferator-activator receptor (PPAR)-beta and collagen (types I and III) at day 7, 21, 30, 60, 90, 120 post-wounding. Immunohistochemical analysis, reverse transcription-quantitative PCR and western blot were used in the present study. Hematoxylin and Eosin (HE) Staining revealed significant differences in the histologic characteristics between TGF-beta 1 treated and saline-treated (control) scars. Exogenous TGF-beta 1 treatment was found to increase the expression of TGF-beta 1 at the early stage of scaring, as well as to increase the expression of PPAR-beta and collagen I/III at all stages of scar formation. Comparison of the gene expression among PPAR-beta, collagen and TGF-beta 1 revealed that TGF-beta 1 may induce PPAR-beta and collagen expression at the early stage of scarring, while PPAR-beta may be the major promoter of collagen at the later stage of scarring. In conclusion, the present study contributes toward an improved understanding of the biological activities of TGF-beta 1 during hypertrophic scar formation.