Background: Taxifolin is a flavanonol with efficacious cytoprotective properties, such as anti-inflammatory, antioxidant, anticancer, hepatoprotective, and nephroprotective effects. However, the potential protective effects of taxifolin against gentamicin-induced ototoxicity have not been confirmed. In this study, the possible mechanisms underlying the effects of taxifolin on gentamicininduced death of UB/OC-2 cochlear cells were investigated. Methods: Mouse cochlear UB/OC-2 cells with or without taxifolin pretreatment were exposed to gentamicin, and the effects on cytotoxicity, reactive oxygen species (ROS) production, mitochondrial permeability transition, and apoptotic marker expression were examined using biochemical techniques, flow cytometry, western blotting, and fluorescent staining. Results: Little or no apparent effect of taxifolin on cell viability was observed at concentrations less than 40 μM. Further investigations showed that gentamicin significantly inhibited cell viability in a concentration-dependent manner. Pretreatment with taxifolin attenuated gentamicin-induced lactate dehydrogenase release, as well as cellular cytotoxicity. In addition, taxifolin significantly prevented gentamicin-induced cell damage by decreasing ROS production, stabilizing mitochondrial membrane potential, and downregulating the mitochondrial pathway of apoptosis. Conclusion: In summary, pretreatment with taxifolin is effective for mitigating gentamicin-induced apoptotic cell death mediated by the mitochondrial pathway. Our data suggest that taxifolin provides a new approach to combat gentamicin-induced ototoxicity.

Gentamicin is an important aminoglycoside antibiotic used in the treatment of gram-negative bacterial infections, but nephrotoxicity and ototoxicity reduce its utility. The autophagy pathway is involved in damage of auditory hair cells. With the aim of developing new strategies for attenuating gentamicin ototoxicity, the present study investigated the otoprotective mechanism of 2,3,4′,5-tetrahydroxystilbene-2-O-β-D-glucoside (THSG) in vitro using the mouse cochlear cell line UB/OC-2. MTT assay demonstrated that gentamicin reduced UB/OC-2 cell viability and western blotting showed that gentamicin upregulated autophagy-related proteins, such as Beclin, autophagy related 5 and LC3-II. THSG significantly attenuated gentamicin-induced cytotoxicity, clearly reduced LDH release observed by LDH assay and decreased the expression of autophagy-related proteins. Reverse-transcription-quantitative (RT-q) PCR and western blotting showed that THSG against gentamicin-induced autophagy via suppressing the expression of Sesn2, at both the mRNA and protein level and a possible involvement of AMP-activated protein kinase (AMPK)/mTOR signaling response. Collectively, the present study demonstrated that THSG decreased gentamicin-induced ototoxicity in UB/OC-2 cochlear cells via the autophagic signaling in regulating Sesn2/AMPK/mTOR pathway. These results suggested that THSG might be a new therapeutic agent with the potential to attenuate gentamicin ototoxicity.

Background/Aim: Gentamicin has been widely prescribed since the last two decades despite its ototoxicity and nephrotoxicity. Bisdemethoxycurcumin (BDMC) is an affordable and safe curcuminoid with medicinal properties. We aimed to understand the effects of BDMC on the gentamicin-induced hair cell damage in mouse cochlear UB/OC-2 cells, in order to elucidate the therapeutic potential of BDMC against gentamicin-induced ototoxicity. Materials and Methods: We quantified the cell membrane potential and examined the regulators and cascade proteins in the intrinsic pathway of hair cell apoptosis. Mouse cochlear UB/OC-2 cells were treated with BDMC before exposure to gentamicin. The effects of BDMC on hair cell viability, mitochondrial function, and apoptosis-related proteins were examined by flow cytometry, western blot, and fluorescent staining. Results: Our results revealed that BDMC reversed gentamicin-mediated cycle arrest at the G 2 /M phase, stabilizing the mitochondrial membrane potential, decreasing cleaved caspase proteins, and successfully reversing hair cell apoptosis. Conclusion: BDMC is a potential agent for reducing gentamicin-induced ototoxicity.Gentamicin is a broad-spectrum aminoglycoside (AG) antibiotic effective against aerobic gram-negative and grampositive bacteria. It is known for its efficacy against neonatal sepsis and tuberculosis (1-3). Owing to their affordable cost, AGs have been widely used in the last two decades, especially in developing countries. However, gentamicin has serious adverse effects such as ototoxicity and nephrotoxicity (4-6).For several years, researchers have attempted to find novel therapies against gentamicin-induced ototoxicity (6-8).

A novel technique utilizing the adsorptive potential of immobilized multi-walled carbon nanotubes (I-MWCNT) in hollow fiber liquid-phase microextraction (HF-LPME) was developed for the determination of diuretics in urine. In this study, the potential of carbon nanotubes as a sorbent for three-phase liquid-phase microextraction of diuretics from urine samples was evaluated. Analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A novel method was applied to detect acetazolamide (AAA), chlorothiazide (CTA), hydrochlorothiazide (HCT), hydroflumethiazide (HFT), clopamide (CA), trichlormethiazide (TCM), althiazide (AT) and bendroflumethiazide (BFT) in urine. Two-step extractions using different times and temperatures for each step were adopted. Parameters influencing the extraction efficiency, including the extraction solvent, sample pH, salt concentration, extraction time and extraction temperature were systematically optimized. Under the resulting optimal extraction conditions, this method showed good linearity over an analytes concentration range of 1 to 1000 ng/mL, high extraction repeatability with relative standard deviations of less than 6%, and low detection limits (0.09 to 0.51 ng/mL). The application of the methods to the determination of diuretics in real samples was tested by analyzing urine samples of patient.

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