The Effects of Experimental Intratympanic Steroid Administration on Organ of Corti Type 1 Spiral Ganglion

Abstract

Introduction It is unclear how effective is the intratympanic (IT) steroid treatment on organ of Corti type 1 spiral ganglion, its optimal dosage and frequency of administration. The effect of dexamethasone on cochlear functions in individuals with a normal hearing ability is also unknown.

Objective The aim of this study was to evaluate, at the electrophysiological and ultrastructural levels, the effect of IT dexamethasone administration in guinea pigs with normal hearing on organ of Corti type 1 spiral ganglion.

Methods A total of 20 guinea pigs (n = 40 ears) whose hearing was detected to be normal by electrophysiological tests were included in the study and randomly divided into 6 groups. Four groups were considered study groups, while 2 groups were considered control groups. Dexamethasone was administered intratympanically in doses of 2 mg/mL and 4 mg/mL in the guinea pigs in the study groups. The animals in the control groups received physiological saline in equal doses as the study groups. All interventions were performed under general anesthesia, and the electrophysiological tests were repeated following the IT injections.

Results No statistically significant differences were found among the groups when the IT injections were evaluated in terms of the electrophysiological measurements (p > 0.05). The ultrastructural evaluation showed a cellular mitochondrial increase in the spiral ganglions of the cochlea in the groups in which dexamethasone was administered in a dose of 4 mg/mL.

Conclusion According to the findings of this study, it can be suggested that the IT injection of dexamethasone is safe, and when applied in a dose of 4 mg/mL, it increases metabolic activity at the cellular level.

Keywords

intratympanic - spiral ganglion - guinea pig - microscopy - dexamethasone

• References

• 1 Schimer BP, Parker KL. Adrenocorticotropic Hormone Adrenocortical Steroids and Their Synthetic Analogs; Inhibitors of the Synthesis and Actions of Adrenocortical Hormones. In: Hardman JG, Gilman AG, Limbird LE. (Eds). The Pharmacological Basis of Therapeutics. 9th ed. New York: McGraw-Hill companies; 1996: 1459-85
• 2 Chrousos GP, Margioris AN. Adrenocorticosteroids & Adrenocortical Antagonists. In: Katzung BG. (Ed). Basics and Clinical Pharmacology. 8th ed. San Francisco: McGraw-Hill companies; 2001: 660-78
• 3 Itoh A, Sakata E. Treatment of vestibular disorders. Acta Otolaryngol Suppl 1991; 481: 617-623
• 4 Sennaroglu L, Sennaroglu G, Gursel B, Dini FM. Intratympanic dexamethasone, intratympanic gentamicin, and endolymphatic sac surgery for intractable vertigo in Meniere's disease. Otolaryngol Head Neck Surg 2001; 125 (05) 537-543
• 5 Yamazaki T, Hayashi M, Komatsuzaki A. Intratympanic gentamicin therapy for Menière's disease placed by a tubal catheter with systematic isosorbide. Acta Otolaryngol Suppl 1991; 481: 613-616
• 6 Nedzelski JM, Schessel DA, Bryce GE, Pfleiderer AG. Chemical labyrinthectomy: local application of gentamicin for the treatment of unilateral Menière's disease. Am J Otol 1992; 13 (01) 18-22
• 7 McFeely WJ, Singleton GT, Rodriguez FJ, Antonelli PJ. Intratympanic gentamicin treatment for Meniere's disease. Otolaryngol Head Neck Surg 1998; 118 (05) 589-596
• 8 Yılmaz İ, Akkuzu B, Özlüoğlu LN. İntratimpanik uygulamalar popüler bir yöntem üzerine derleme. Otoskop. 2003; 3: 145-155
• 9 Chandrasekhar SS, Rubinstein RY, Kwartler JA. , et al. Dexamethasone pharmacokinetics in the inner ear: comparison of route of administration and use of facilitating agents. Otolaryngol Head Neck Surg 2000; 122 (04) 521-528
• 10 Alles MJRC, der Gaag MA, Stokroos RJ. Intratympanic steroid therapy for inner ear diseases, a review of the literature. Eur Arch Otorhinolaryngol 2006; 263 (09) 791-797
• 11 Uzun C, Yağız R, Koten M, Adalı MK, Karasalihoğlu AR. Kobaylarda transient evoked otoakustik emisyon ölçüm yöntemi. Kulak Burun Bogaz Ihtis Derg 2000; 7: 97-105
• 12 Ceylan K, Ünlü İ, Samim E. İntratimpanik steroid tedavisi. Otoscope. 2004; 3: 108-115
• 13 Lalwani AK, McGuire JF. Koklea ve labirentin farmakolojik tedavisi (çeviri: S. Yetişer). Koç C (Editör). Cummings Otolaringoloji Baş ve Boyun Cerrahisi cilt 4, Ankara: Güneş Tıp Kitabevleri; 2007: s.2944-76
• 14 Parnes LS, Sun AH, Freeman DJ. Corticosteroid pharmacokinetics in the inner ear fluids: an animal study followed by clinical application. Laryngoscope 1999; 109 (7 Pt 2): 1-17
• 15 Barrs DM, Keyser JS, Stallworth C, McElveen Jr JT. Intratympanic steroid injections for intractable Ménière's disease. Laryngoscope 2001; 111 (12) 2100-2104
• 16 Araújo MF, Oliveira CA, Bahmad Jr FM. Intratympanic dexamethasone injections as a treatment for severe, disabling tinnitus: does it work?. Arch Otolaryngol Head Neck Surg 2005; 131 (02) 113-117
• 17 Yilmaz I, Yilmazer C, Erkan AN, Aslan SG, Ozluoglu LN. Intratympanic dexamethasone injection effects on transient-evoked otoacoustic emission. Am J Otolaryngol 2005; 26 (02) 113-117
• 18 Uğur MZ, Önal HK, Akdağ H, Arslanoğlu S, Gökçe AH, Etit D. İntratimpanik deksametazonun guinea piglerinde işitme eşikleri ve koklea histopatolojisi üzerine etkisi. KBB Postası. 2007; 1: 4-8
• 19 Shirwany NA, Seidman MD, Tang W. Effect of transtympanic injection of steroids on cochlear blood flow, auditory sensitivity, and histology in the guinea pig. Am J Otol 1998; 19 (02) 230-235