OTOLOGY Quantitative measurement of m-RNA levels to assess expression of cyclooxygenase-II, inducible nitric oxide synthase and 12-lipoxygenase genes in middle ear cholesteatoma Tolgahan C ¸ atlı • Yıldırım Bayazıt • AkınYılmaz • Adnan Menevs ¸e • Ozan Go ¨kdog ˘an • Nebil Go ¨ksu • Suat O ¨ zbilen Received: 24 April 2013 / Accepted: 19 June 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract To assess expression of three main inflamma- tory genes, COX-II, ALOX-12 and i-NOS, quantitatively at transcriptional level in cholesteatoma matrix tissue. Ten patients who have chronic otitis media with primary acquired cholesteatoma were included in this study. Tissue samples obtained from cholesteatoma matrix and external ear canal skin (control tissue). Expression of the targeted genes (COX-II, i-NOS and LOX-12) was assessed using real-time quantitative polymerase chain reaction (RT-PCR) technique. The amount of COX2 mRNA was significantly higher in cholesteatoma matrix at transcriptional level (p = 0.038). There was no statistically significant differ- ence regarding expression of iNOS and LOX12 mRNA levels (p [ 0.05). There is a significant overexpression of the mRNA of COX-II in cholesteatoma matrix, which indicates a difference between the normal skin and cho- lesteatoma matrix at molecular level. COX-II gene over- expression seems to be associated with pathogenesis of cholesteatoma. This molecular change is similar to the molecular abnormalities observed in some benign and malignant neoplasms. Invasive and locally destructive nature of cholesteatoma may be due to COX-II overex- pression. Absence of an increase in the gene expressions of i-NOS and LOX-12 in cholesteatoma matrix suggests that these mediators may not be related with the pathogenesis and evolution of cholesteatoma. Keywords Cholesteatoma Á COX-II Á iNOS Á LOX-12 Introduction Cholesteatoma is a histologically benign, locally aggres- sive and destructive epidermoid tissue located in the tem- poral bone. Cholesteatoma also has an inflammatory nature which brings out the bone resorption and granulation tissue at the affected site of the temporal bone. Cholesteatoma matrix produces various cytokines (IL-1 alpha, IL-1 beta, IL-6 and interferon-beta as well as parathyroid-hormone- related protein) [1, 2], which aggravate inflammation by causing a quantitative increase in the inflammatory enzymes, COX-II (cyclooxygenase-II), LOX-12 (lipooxy- genase-12) and i-NOS (inducible nitric oxide synthase). These inflammatory mediators function in the inflamma- tory pathways, and the cytokines produced during the inflammatory reactions cause damage in the tissues [3–5]. Cytokines, prostaglandins, nitric oxide and growth fac- tors are released in the chronic inflammatory process in cholesteatoma and may initiate osteoclast recruitment and bone resorption. Bone resorption begins with the accumu- lation of mononuclear cells from bone marrow, and mul- tinucleation of these cells then becomes osteoclasts. These specialized cells are able to resorb the organic and inor- ganic matrix of bone. Bone resorption is also controlled by an obligatory relationship between the local osteoblasts and osteoclasts. These microscopic events cause destruction of the bone and ossicles, and in turn, complications [6]. COX enzyme group has two isoforms (COX-I and COX-II) which are located primarily in the nervous system [7]. LOX enzyme has three isoforms (LOX-5, LOX-12 and LOX-15) which are produced from arachidonic acid, and act as bioactive mediators of inflammation [8, 9]. NOS is T. C ¸ atlı (&) Á Y. Bayazıt Á O. Go ¨kdog ˘an Á N. Go ¨ksu Á S. O ¨ zbilen ENT Department, Gazi University, Ankara, Turkey e-mail: tcatli80@hotmail.com A. Yılmaz Á A. Menevs ¸e Department of Medical Biology and Genetics, Gazi University, Ankara, Turkey 123 Eur Arch Otorhinolaryngol DOI 10.1007/s00405-013-2614-x