Hong Wenzhou, Khampang Pawjai, Kerschner Abigail R, Mackinnon Alexander C, Yan Ke, Simpson Pippa M, Kerschner Joseph E
Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, USA.
Department of Pathology, Medical College of Wisconsin, USA.
Int J Pediatr Otorhinolaryngol. 2019 Oct;125:134-140. doi: 10.1016/j.ijporl.2019.07.002. Epub 2019 Jul 4.
Gel-forming mucins (GFMs) play important roles in otitis media (OM) pathogenesis. Increased mucin expression is activated by pathogens and proinflammatory cytokines. Bacterial biofilms influence inflammation and resolution of OM and may contribute to prolonged mucin production. The influence of specific pathogens on mucin expression and development of chronic OM with effusion (OME) remains an area of significant knowledge deficit.
To assess the relationship between GFM expression, specific pathogens, middle ear mucosal (MEM) changes, biofilm formation, and antibiotic utilization.
Mixed gender chinchillas were inoculated with nontypeable Haemophilus influenzae (NTHi) strain 86028NP or Streptococcus pneumoniae (SP) strain TIGR4 via transbulla injection. Antibiotic was administered on day 3-5 post inoculation. GFM expression was measured by quantitative PCR. Biofilm formation was identified and middle ear histologic changes were measured.
SP infection resulted in higher incidence of biofilm and ME effusion compared with NTHi infection. However, NTHi persisted in the ME longer than SP with no substantive bacterial clearance detected on day 10 compared with complete bacterial clearance on day 10 for 50-60% of the SP-infected chinchillas. Both infections increased MEM inflammatory cell infiltration and thickening. NTHi upregulated the Muc5AC, Muc5B and Muc19 expression on day 10 (p = 0.0004, 0.003, and 0.002 respectively). SP-induced GFM upregulations were trended toward significant. In both NTHi and SP infections, the degree of GFM upregulation had a direct relationship to increased MEM hypertrophy, inflammatory cell infiltration and biofilm formation. Antibiotic treatment reduced the incidence of ME effusion and biofilm, limited the MEM changes and reversed the GFM upregulation. In NTHi infection, the rate of returning to baseline level of GFMs in treated chinchillas was quicker than those without treatment.
In an animal model of OM, GFM genes are upregulated in conjunction with MEM hypertrophy and biofilm formation. This upregulation is less robust and more quickly ameliorated to a significant degree in the NTHi infection with appropriate antibiotic therapy. These findings contribute to the understanding of pathogen specific influences on mucin expression during OM pathogenesis and provide new data which may have implications in clinical approach for OM treatment.
凝胶形成性黏蛋白（GFMs）在中耳炎（OM）发病机制中起重要作用。病原体和促炎细胞因子可激活黏蛋白表达增加。细菌生物膜影响OM的炎症和转归，可能导致黏蛋白产生时间延长。特定病原体对慢性分泌性中耳炎（OME）中黏蛋白表达和发展的影响仍是一个存在重大知识空白的领域。
评估GFM表达、特定病原体、中耳黏膜（MEM）变化、生物膜形成和抗生素使用之间的关系。
通过经鼓泡注射，将不可分型流感嗜血杆菌（NTHi）菌株86028NP或肺炎链球菌（SP）菌株TIGR4接种于雌雄混合的栗鼠。在接种后第3 - 5天给予抗生素。通过定量PCR测量GFM表达。鉴定生物膜形成并测量中耳组织学变化。
与NTHi感染相比，SP感染导致生物膜和中耳积液发生率更高。然而，NTHi在中耳持续存在的时间比SP长，在第10天未检测到实质性细菌清除情况，而50 - 60%的SP感染栗鼠在第10天细菌被完全清除。两种感染均增加了MEM炎性细胞浸润和增厚。NTHi在第10天上调了Muc5AC、Muc5B和Muc19表达（分别为p = 0.0004、0.003和0.002）。SP诱导的GFM上调有显著趋势。在NTHi和SP感染中，GFM上调程度与MEM肥大、炎性细胞浸润和生物膜形成增加直接相关。抗生素治疗降低了中耳积液和生物膜的发生率；限制了MEM变化并逆转了GFM上调。在NTHi感染中，接受治疗的栗鼠中GFM恢复到基线水平的速度比未治疗的栗鼠更快。
在OM动物模型中GFM基因与MEM肥大和生物膜形成同时上调。在适当的抗生素治疗下，这种上调在NTHi感染中不那么强烈，且在很大程度上能更快得到改善。这些发现有助于理解病原体在OM发病机制中对黏蛋白表达的特异性影响，并提供了可能对OM临床治疗方法有影响的新数据。
