The possible mechanism of Hippophae fructus oil applied in tympanic membrane repair identified based on network pharmacology and molecular docking.

OBJECTIVE: This study aimed to explore the mechanisms of Hippophae fructus oil (HFO) in the treatment of tympanic membrane (TM) perforation through network pharmacology-based identification. METHODS: The compounds and related targets of HFO were extracted from the TCMSP database, and disease information was obtained from the OMIM, GeneCards, PharmGkb, TTD, and DrugBank databases. A Venn diagram was generated to show the common targets of HFO and TM, and GO and KEGG analyses were performed to explore the potential biological processes and signaling pathways. The PPI network and core gene subnetwork were constructed using the STRING database and Cytoscape software. A molecular docking analysis was also conducted to simulate the combination of compounds and gene proteins. RESULTS: A total of 33 compounds and their related targets were obtained from the TCMSP database. After screening the 393 TM-related targets, 21 compounds and 22 gene proteins were selected to establish the network diagram. GO and KEGG enrichment analyses revealed that HFO may promote TM healing by influencing cellular oxidative stress and related signaling pathways. A critical subnetwork was obtained by analyzing the PPI network with nine core genes: CASP3, MMP2, IL1B, TP53, EGFR, CXCL8, ESR1, PTGS2, and IL6. In addition, a molecular docking analysis revealed that quercetin strongly binds the core proteins. CONCLUSION: According to the analysis, HFO can be utilized to repair perforations by influencing cellular oxidative stress. Quercetin is one of the active compounds that potentially plays an important role in TM regeneration by influencing 17 gene proteins.

Early age conductive hearing loss causes audiogenic seizure and hyperacusis behavior.

Recent clinical reports found a high incidence of recurrent otitis media in children suffering hyperacusis, a marked intolerance to an otherwise ordinary environmental sound. However, it is unclear whether the conductive hearing loss caused by otitis media in early age will affect sound tolerance later in life. Thus, we have tested the effects of tympanic membrane (TM) damage at an early age on sound perception development in rats. Two weeks after the TM perforation, more than 80% of the rats showed audiogenic seizure (AGS) when exposed to loud sound (120 dB SPL white noise, < 1 min). The susceptibility of AGS lasted at least sixteen weeks after the TM damage, even the hearing loss recovered. The TM damaged rats also showed significantly enhanced acoustic startle responses compared to the rats without TM damage. These results suggest that early age conductive hearing loss may cause an impaired sound tolerance during development. In addition, the AGS can be suppressed by the treatment of vigabatrin, acute injections (250 mg/kg) or oral intakes (60 mg/kg/day for 7 days), an antiepileptic drug that inhibits the catabolism of GABA. c-Fos staining showed a strong staining in the inferior colliculus (IC) in the TM damaged rats, not in the control rats, after exposed to loud sound, indicating a hyper-excitability in the IC during AGS. These results indicate that early age conductive hearing loss can impair sound tolerance by reducing GABA inhibition in the IC, which may be related to hyperacusis seen in children with otitis media.

Attenuation of Fos expression to airpuff startle stimuli following tympanic membrane rupture.

The airpuff startle stimulus consists of two modalities, tactile and acoustic. Tympanic membrane rupture (TMR) effectively deafens a rat, thus preventing it from perceiving the acoustic component of the airpuff and permitting study of the tactile component in isolation. Previous studies have shown that the tactile modality is sufficient to drive the cardiovascular response to the airpuff, but cannot elicit the full behavioral startle response. In the present study Fos protein was used as a marker of neuronal activation to identify brain regions activated by the airpuff in both intact and TMR rats. Results show an attenuation of Fos expression following TMR in the dorsal and ventral cochlear nuclei, ventral nucleus of the lateral lemniscus and medial geniculate nucleus. In contrast, Fos expression following TMR was unchanged in the locus coeruleus, the laterodorsal tegmental nucleus, the supramammilary nucleus, and the ventromedial hypothalamic nucleus. Analysis of behavioral data confirmed that the startle response to the airpuff was diminished following TMR. These data are the first of which we know to employ an immediate early gene approach to discriminate between brain regions activated by the tactile and acoustic startle stimulus modalities. The results are discussed in terms of the classical acoustic startle circuit, and the central autonomic pathways activated by the tactile component of the airpuff.