TY - JOUR
T1 - Middle ear inflammation of rat induced by urban particles
AU - Park, Moo Kyun
AU - Chae, Sung Won
AU - Kim, Hee Bok
AU - Cho, Jae Gu
AU - Song, Jae Jun
N1 - Funding Information:
This study was supported by the Korea Ministry of Environment as part of “The Environmental Health Action Program" (2012001360002).
Funding Information:
This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government (NSSC) (no. 2012M2A2A6035679 ).
Publisher Copyright:
© 2014 Elsevier Ireland Ltd.
PY - 2014/12/1
Y1 - 2014/12/1
N2 - Objective: The aim of this study was to evaluate the histologic change of middle ear mucosa and the expression levels of epithelial sodium channel ( ENaC) subunits and mucin production genes, after the injection of urban particulate matter (UPM) into the middle ear cavity of rats. Methods: Fifty pathogen-free, male Sprague Dawley rats were assigned to the study. Transtympanic injection of UPM solution (300. μg/ml, 50. μl) was made into the middle ear cavity of rats. Rats were sacrificed at day 1 (group1); day 3 (group2); day 5 (group3); and day 14 (group4) after the procedure. The expression levels of ENaC subunits ( α, β and γ) and mucin producing genes ( MUC5AC and MUC5B) were analyzed using semi-quantitative real-time reverse transcriptase-polymerase chain reaction. Thickness of middle ear mucosa was measured and analyzed. Result: After transtympanic injection, the thickness of middle ear mucosa increased significantly on day 1, 3 and 5 ( p<. 0.05) and was normalized on day 14, compared to the control group. Inflammatory changes observed in the middle ear mucosa were subepithelial widening, inflammatory cell infiltration and vascular space widening on day 1, 3 and 5. These changes had reverted to normal on day 14. The level of ENaC-α expression decreased 0.60 fold on day 1 ( p<. 0.05), but was normalized thereafter. The level of ENaC-β and γ decreased 0.39 and 0.27 fold, respectively, on day 1, was normalized on days 3 and 5, and increased 2.30 and 2.47 fold on day 14, respectively ( p<. 0.05). The level of MUC5AC expression increased 1.97-fold on day 1 ( p<. 0.05) and 2.58-fold on day 5 ( p<. 0.05), but was normalized on day 14. The level of MUC5B expression increased 5.4-fold on day 1, 3.14-fold on day 3, 3.85-fold on day 5, and 2.46-fold on day 14, respectively ( p<. 0.05). Conclusion: Transtympanic injection of UPM solution into the middle ear cavity of rat induced a characteristic inflammatory response and altered gene expression related with inflammation and mucin production. These findings provide a useful clue for the understanding of how air pollutants, particularly UPM, contribute to the development of otitis media.
AB - Objective: The aim of this study was to evaluate the histologic change of middle ear mucosa and the expression levels of epithelial sodium channel ( ENaC) subunits and mucin production genes, after the injection of urban particulate matter (UPM) into the middle ear cavity of rats. Methods: Fifty pathogen-free, male Sprague Dawley rats were assigned to the study. Transtympanic injection of UPM solution (300. μg/ml, 50. μl) was made into the middle ear cavity of rats. Rats were sacrificed at day 1 (group1); day 3 (group2); day 5 (group3); and day 14 (group4) after the procedure. The expression levels of ENaC subunits ( α, β and γ) and mucin producing genes ( MUC5AC and MUC5B) were analyzed using semi-quantitative real-time reverse transcriptase-polymerase chain reaction. Thickness of middle ear mucosa was measured and analyzed. Result: After transtympanic injection, the thickness of middle ear mucosa increased significantly on day 1, 3 and 5 ( p<. 0.05) and was normalized on day 14, compared to the control group. Inflammatory changes observed in the middle ear mucosa were subepithelial widening, inflammatory cell infiltration and vascular space widening on day 1, 3 and 5. These changes had reverted to normal on day 14. The level of ENaC-α expression decreased 0.60 fold on day 1 ( p<. 0.05), but was normalized thereafter. The level of ENaC-β and γ decreased 0.39 and 0.27 fold, respectively, on day 1, was normalized on days 3 and 5, and increased 2.30 and 2.47 fold on day 14, respectively ( p<. 0.05). The level of MUC5AC expression increased 1.97-fold on day 1 ( p<. 0.05) and 2.58-fold on day 5 ( p<. 0.05), but was normalized on day 14. The level of MUC5B expression increased 5.4-fold on day 1, 3.14-fold on day 3, 3.85-fold on day 5, and 2.46-fold on day 14, respectively ( p<. 0.05). Conclusion: Transtympanic injection of UPM solution into the middle ear cavity of rat induced a characteristic inflammatory response and altered gene expression related with inflammation and mucin production. These findings provide a useful clue for the understanding of how air pollutants, particularly UPM, contribute to the development of otitis media.
KW - Epithelial sodium channel (ENaC)
KW - MUC5AC
KW - MUC5B
KW - Otitis media (OM)
KW - Urban particulate matter (UPM)
UR - http://www.scopus.com/inward/record.url?scp=84919484386&partnerID=8YFLogxK
U2 - 10.1016/j.ijporl.2014.10.011
DO - 10.1016/j.ijporl.2014.10.011
M3 - Article
C2 - 25458159
AN - SCOPUS:84919484386
VL - 78
SP - 2193
EP - 2197
JO - International Journal of Pediatric Otorhinolaryngology
JF - International Journal of Pediatric Otorhinolaryngology
SN - 0165-5876
IS - 12
ER -