To explore myringosclerotic tissue levels of two bone modeling markers: osteopontin (OPN)
and osteoprotegerin (OPG) in experimentally-induced, histologically-confirmed myringosclerosis (MS). Materials
& Methods: The right middle ear of 24 normal healthy growing male Wister rats was inoculated, via transtympanic
access, by Streptococcus pneumoniae type 3, after a period of 8 weeks the tympanic membrane (TM) was examined
Otomicroscopically for transparency and graded as normal TM, mild or marked opacification. Then, tympanic
bullae were removed and a part of myringosclerotic plaque was excised for ELISA estimation of tissue extract levels
of OPN and OPG and the remainder of the TM was stained with hematoxylin-eosin for light microscopic grading of
TM inflammation according to extent of calcification into 5 grades. Results: 20 ears developed otoscopically
defined myringosclerotic changes, 14 ears showed mild and 6 had marked opacification that was localized in 4 ears
and diffuse in 2 ears. Histological examination reported inflammation of grade III in 7, grade IV in 13 and grade V
in 4 specimens. Mean estimated tissue extract level of OPN and OPG in studied animals were significantly higher
compared to control animals with a positive significant correlation between histological grading and tissue-extract
levels of both OPG and OPN and a positive significant correlation between otoscopic grading and tissue-extract
levels of OPG, but the correlation was non-significant with OPN Conclusion: Increased myringosclerotic tissue
extract levels of both bone modeling markers indicated their possible role in initiation and/or progression of sclerotic
changes in TM after chronic suppurative otitis media.
[Ahmed Al-Shal, Nahla E. El-Azab, Mohamed Khaled Mohamed Mahfouz. Biochemical Determination of Tissue
Ossification Markers in Experimentally-induced Myringosclerosis.