Quantitative measurement of m-RNA levels to assess expression of cyclooxygenase-II, inducible nitric oxide synthase and 12-lipoxygenase genes in middle ear cholesteatoma

Abstract

To assess expression of three main inflammatory 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 difference 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 cholesteatoma matrix at molecular level. COX-II gene overexpression 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 overexpression. 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.

Nitric Oxide Is Locally Produced in the Human Middle Ear and Is Reduced by Acquired Cholesteatoma

“…Consistent with our observations, Lee et al (27) did not see a significant change in the iNOS expression in cholesteatoma ears. In contrast, Çatli et al (11) reported a lower expression of iNOS in cholesteatoma ears. It is important to recognize that in the studies of Lee et al (27) and Çatli et al (11), cholesteatoma matrix was compared with controls from skin in the ear canal, whereas in our study the middle ear mucosa was targeted.…”

“…In contrast, Çatli et al (11) reported a lower expression of iNOS in cholesteatoma ears. It is important to recognize that in the studies of Lee et al (27) and Çatli et al (11), cholesteatoma matrix was compared with controls from skin in the ear canal, whereas in our study the middle ear mucosa was targeted. The associations between OME and cholesteatoma and other types of chronic otitis media imply that the answer to the enigma of cholesteatoma would probably be found within the middle ear (1).…”

“…Furthermore, iNOS is found in biopsies from the TM in COM and OME (8), in adenoid tissue (9), and in middle ear secretion in OME (10). NOS is also demonstrated in ears affected by cholesteatoma, equally expressed in matrix and skin from the ear canal (11).…”