Rosmarinic Acid Alleviates Effects of Inflammatory Response and Hearing Impairment in Rats with Secretory Otitis Media
HU Chengli
KANG Houyong
ZHAO Ran
Abstract：Objective To investigate the impacts of rosmarinic acid on inflammatory response and hearing loss in rats with secretory otitis media(SOM)and the role of interleukin(IL)-6/signal transducers and activators of transcription 3(STAT3)signaling pathway.Methods Select 72 healthy male SD rats,SOM in rats was induced by ovalbumin(OVA).Rats with SOM received rosmarine-L,M,H,or rosmarinic acid+Colivelin treatments,or no treatment(n=12 in each group).A sham operation group was also included(n=12).After drug intervention,endoscopy was used to examine the tympanic membrane;ELISA was used to detect the levels of inflammatory related factors IL-6,tumor necrosis factor-α(TNF-α),IL-1β in rat serum and IL-6 in middle ear lavage;HE staining was used to observe histopathological changes in middle ear mucosa;RT-qPCR was used to detect the levels of IL-6/STAT3 pathway related genes in middle ear mucosa;Western blot was used to detect the levels of IL-6/STAT3 pathway related proteins in rat middle ear mucosa.Results Compared with the sham operation group,untreated rats with SOM showed a large amount of effusion,engorged blood vessels on the tympanic membrane,increased middle ear mucosa thickness,epithelial necrosis,a large number of inflammatory cell infiltration,and significantly increased levels of inflammation related factors IL-6,TNF-α,IL-1β in serum,IL-6 in middle ear lavage,mRNA levels of IL-6,STAT3 in middle ear mucosal,and protein levels of p-STAT3/STAT3,IL-6,and JAK2(P＜0.05).In contrast,animals treated with rosmarinic acid L,M,and H showed a return to transparent tympanic membrane,with clear structural landmarks,reduced fluid accumulation,gradual restoration of middle ear mucosal structure,and reduced inflammatory cell infiltration,with significantly reduced levels of inflammation related factors IL-6,TNF-α,IL-1β in serum,IL-6 in middle ear lavage,mRNA levels of IL-6,STAT3 in middle ear mucosal,and protein levels of p-STAT3/STAT3,IL-6,and JAK2(P＜0.05).Compared with the rosmarinic acid-H treated group,rats in the rosmarinic acid+Colivelin treated group showed dark tympanic membrane with a large amount of effusion,fuzzy structural landmarks and engorged blood vessels,as well as increased middle ear mucosa thickness,epithelial necrosis,a large amount of inflammatory cell infiltration,and significantly increased levels of inflammation related factors IL-6,TNF-α,IL-1β in serum,IL-6 in middle ear lavage,mRNA levels of IL-6,STAT3 in middle ear mucosal,and protein levels of p-STAT3/STAT3,IL-6,and JAK2(P＜0.05).Conclusion Rosmarinic acid may alleviate inflammation and hearing loss in SOM by inhibiting the IL-6/STAT3 signaling pathway in rats.
Keywords：rosmarinic acidIL-6/STAT3 signaling pathwaysecretory otitis mediaratshearing loss
Publication Date：2025-04-15
Pages：6( 267-272 )