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A Comparative Study of Drug Delivery Methods Targeted to the Mouse Inner Ear: Bullostomy Versus Transtympanic Injection
Published on: March 8, 2017
[A mouse model for acute otitis media via transbullar injection]
Yifei Huang1, Chunfang Jin1, Yun Xiang1
1Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
Objective:
To develop a mouse model for acute otitis media (AOM) via transbullar injection method and evaluate its feasibility and practicability.
Methods:
The middle ears (ME) of C57BL/6 mice were inoculated via transbullar injection method with 5 µl streptococcus pneumoniae (S.pn) 19F suspension (1×10(7) CFU/ml), and the control group was inoculated equivalent phosphate buffered solution (PBS). Behavior changes were observed daily following inoculation. The ME tissues for histological examination and the middle ear lavage fluid (MELF) for total cells quantification, S.pn load determination and cytokines measurement were collected at 12 h, day 1, 2, 3, 5, 7 after inoculation, respectively.
Results:
Within 24 hours after instillation, the density of S.pn and the level of acute inflammatory cytokines in ME cavity increased rapidly, some mucosal hyperplasia was evident and leukocytic infiltration (primarily neutrophils) began. The level of ME inflammatory response reached maximal at 2-3 days after inoculation, with extensive effusion, leukocytic infiltration and mucosal thickening. Meanwhile, the density of S.pn decreased gradually. Bacterial clearance was completed by day 5 with extensive resolution of ME inflammation, although mucosal hyperplasia did not resolute until day 7.
Conclusion:
A mouse model for AOM is successfully established via transbullar injection method, laying foundation for future study of AOM.
Insights
A novel mouse model for acute otitis media (AOM) was successfully developed using a transbullar injection method. This model effectively replicates AOM pathology, aiding future research into the condition.
Area of Science:
- Otolaryngology
- Infectious Diseases
- Animal Models
Background:
- Acute otitis media (AOM) is a common childhood infection.
- Developing reliable animal models is crucial for understanding AOM pathogenesis and testing therapeutics.
Purpose of the Study:
- To establish and validate a transbullar injection mouse model for acute otitis media (AOM).
- To assess the feasibility and practicality of this novel AOM mouse model.
Main Methods:
- C57BL/6 mice were inoculated with Streptococcus pneumoniae (S.pn) via transbullar injection.
- Control groups received phosphate-buffered saline (PBS).
- Middle ear tissues, lavage fluid, and behavioral changes were analyzed at various time points post-inoculation.
Main Results:
- Rapid increase in S.pn density and inflammatory cytokines within 24 hours.
- Maximal inflammatory response, effusion, and leukocytic infiltration observed at 2-3 days.
- Bacterial clearance by day 5, with inflammation resolving by day 7, though mucosal hyperplasia persisted.
Conclusions:
- The transbullar injection method successfully established a reproducible mouse model for AOM.
- This model provides a valuable platform for future investigations into AOM.
- The model demonstrates key pathological features and temporal progression of AOM.
