The Effects of interleukin-18 on Middle Ear Inflammation in the Rat Model of Otitis Media with Effusion / 听力学及言语疾病杂志

ABSTRACT

Objective To investigated the effects of IL -18 on middle ear allergic inflammation in rat model of OME .Methods Eighteen SD rats were randomly divided into three groupgroup A(control group ,n=12 ears) , group B (OME model group ,n=12 ears) ,group C (IL -18 injectiion group ,n=12 ears) .The rat model of OME was established by sensitizing with ovalbumin (OVA) and later challenging in tympanic bullae .Recombinant rat IL-18 (1 μg ,+0 .2 ml saline ,) were injected in group C at 1 ,2 ,7 ,8 ,15 ,16 day .At the same time sacle ,0 .2 ml sa-line ,instead of IL -18 ,were intraperitoneal injection in group A and B .The morphologic changes of the middle ear epithelial cells and inflammatory cells infiltration were observed under light microscope .The level of IFN -γand IL-4 in tympanic lavage fluid(TLF) were determined by ELISA .Results Pathological examination showed that middle ear mucosa inflammation and eosinophil infiltration in group C were no less severe than group B .The numbers of neutrophils in group C increased significantly compraring with group B (P0 .05) ,while significantly greater than that in group A (P0 .05) .Addtionally ,there was no significant difference in the ratio of Th1 /Th2(IFN -γ/IL -4)between group B and group C (P>0 .05) . Conclusion IL -18 acts as an immune regulatory factors ,significantly increases Th1 cytokine IFN -γ.Although to some extent alleviate the OME rat middle ear Th1 /Th2 imbalance ,there is still excessive activation of Th cells . Th1 and Th2 cells factor are excessive for the secretion disorder of the immune response status .The OME rat mid-dle ear allergic inflammation has not been fundamentally alleviated ,the underlying mechamism should be further studied .