Effects of fibroblast growth factor on the healing process of tympanic membrane perforations in an animal model

Abstract

After traumatic perforation of the tympanic membrane (TM), healing occurs spontaneously in most cases, although occasional perforations will fail to close. Healing of epithelia at any site involves cell movement, with injury providing the stimulus to initiate changes in the behavior of cells that are normally static. Epidermal proliferation at the margins of the TM perforation can be accelerated by using such growth factors as epidermal growth factor, basic fibroblast growth factor (bFGF) and hyaluronan. bFGF is chemotactic and mitogenic for both fibroblasts and endothelial cells and is also mitogenic for keratinocytes. The effect of bFGF is significant in the enhancement of fibroblast production and angiogenesis. In this study, bFGF was used to enhance the healing process of chronic TM perforations in a guinea pig animal model. Chronic perforations were created since acute TMs could heal spontaneously without using any bioactive substance. In all, 30 TMs of 15 guinea pigs were used. A thermal myringotomy loop was employed to create a subtotal TM perforation at the area of the pars tensa. After establishing a permanent, non-infected perforation, bFGF in buffered saline solution was applied as 400 ng/day to 15 ears, while the opposite (control) ear was treated with only saline solution. At 20 days, 13 of 15 perforations treated with bFGF had closed. Light microscopy was used to assess organization of the healed TMs. The effects of bFGF on the healing process of TM perforations were compared in treated and non-treated ears.