Figure 7: Administration of specific PDE4 inhibitors upregulates CYLD and suppresses inflammation in a mouse otitis media model.

mRNA expression of (a) CYLD and (b) pro-inflammatory cytokines was measured in middle ear tissues from C57BL/6J mice ototopically pre- or post-inoculated with Rolipram (50 μg per ear) 3 h before (pretreatment) or 3 h after (post treatment) NTHi inoculation, and inoculated with NTHi for 9 h. (c) Haematoxylin and eosin staining of middle ear tissues from C57BL/6J mice ototopically pre- or post-inoculated with Rolipram (50 μg per ear) 3 h before (pretreatment) or 3 h after (post treatment) NTHi inoculation, and inoculated with NTHi for 9 h (magnification × 400). Scale bar, 20 μm. (d) Thickness of middle ear mucosa in C57BL/6J mice ototopically pre- or post-inoculated with Rolipram and inoculated with NTHi was measured from 15 middle ear tissue sections per experimental group. (e) Mice were transtympanically inoculated with NTHi with or without Rolipram ototopically pre- or post-treatment, and tympanic cavity was observed and recorded under the otoscope. Data in a, b and d are mean±s.d. (n=3 in a and b, and 15 in d). *P<0.05. Statistical analysis was performed using Student’s t-test. Data are representative of three or more independent experiments. CON, control; POST, post-inoculation; PRE, preinoculation.