Immunohistochemical studies of wound healing after monopolar electrocautery and ultrasound submucosal inferior nasal turbinate reduction in sheep

Abstract

Background: Extracellular matrix (ECM) proteins such as fibronectin and collagen III, enzymes such as matrix metalloproteinases and macrophages have been demonstrated to intervene in nasal and paranasal sinuses wound healing. Aim of the study: To compare concentration of ECM proteins, enzymes and the recruitment of macrophages during wound repair after monopolar electrocautery in contrast with ultrasound submucosal surgical tissue reduction of inferior nasal turbinate (INT) tested in sheep. Materials and methods: Prospective controlled study in sheep. Immunostaining for collagen III, fibronectin, CD68 and matrix metalloproteinase-9 (MMP9) was applied in tissue specimens of INT mucosa after monopolar electrocoagulation (MEC) and ultrasound tissue reduction (UTR). Twelve INTs were studied 1, 3 and 8 weeks post-operatively in each interventional group (MEC and UTR) and 5 INTs were studied in animals of the control group (without surgery). The immunoreactivity was quantitatively graded between 0% to 100% immunoreactivity by a blinded senior pathologist. Results: At the end of the study period collagen III, fibronectin and MMP9 were increased in both groups compared to the levels of the control group. When compared to control group, CD68 immunoreactivity was found higher in MEC group but not in UTR group. Fibronectin subepithelial immunoreactivity exhibited a substantial negative correlation with mucosal epithelial cell necrosis, a substantial positive correlation with fibrosis in MEC-treated specimens and a significant positive correlation with sinusoid engorgement in UTR-treated specimens. Collagen III tissue immunoreactivity showed a particularly significant negative correlation with sinusoid engorgement in MEC-treated specimens. Conclusion: Correlation of fibronectin and collagen III immunoreactivity to histopathologic findings suggests different ECM repair processes between MEC and UTR turbinate tissue reduction. The use of CD68 and MMP9 provides additional clues to the mode of actions of these techniques and to the molecular and cellular events of the nasal mucosa wound healing process.