Effect of PDGF-AA on the Healing Process of Tympanic Membrane Perforation and Expression of PDGF-Receptor and Fibronectin

Kim, Soo Whan; Park, Yong Su; Chang, Ki Hong; Yeo, Sang Won; Cho, Seung Ho

Abstract

BACKGROUND: In recent years, repair of tympanic membrane(TM) perforation has been investigated using growth promoting factors. Platelet derived growth factor(PDGF), basic 30kD cytokine, promotes wound healing by its mitogenicity for fibroblast and stimulation of the production of fibronectin and hyaluronic acid.
OBJECTIVES
The purpose of this study is to investigate the effect of PDGF-AA on the healing process of TM perforation.
MATERIALS AND METHODS
The effects of PDGF on the healing process of TM perforation was investigated in rats using the endoscope and light microscope after topical application of 2ug of PDGF-AA or placebo on the edge of TM perforation. The rats were sacrificed at 3, 5, 7, 9, 11, 13 and 15 days following the surgery of TM. The tympanic membranes were also immunohistochemically examined for PDGF-Ralpha and fibronectin to evaluate the mechanism of healing process in the PDGF-treated-TM.
RESULTS
1) Application of PDGF-AA accelerated the healing process of TM perforation and the wound was completely closed at 5 days following surgery. 2) PDGF-AA induced prominent proliferation of the connective tissue layer of TM after surgery, however the connective tissue growth has reduced at 2 weeks following surgery. 3) PDGF-Ralpha was intensely expressed in the epithelial layer of the PDGF-AA-treated TM. 4) Intense expression of fibronectin was observed in the fibroblasts of the connective tissue layer of the PDGF-AA-treated TM.
CONCLUSION
From this study, we concluded that PDGF may play a role in the imm-unoregulation of the healing process of TM perforation and it may be an alternative to the surgical management of TM perforation.