Age-related changes in mitochondrial antioxidant enzyme Trx2 and TXNIP-Trx2-ASK1 signal pathways in the auditory cortex of a mimetic aging rat model: changes to Trx2 in the auditory cortex.

Age-associated degeneration in the central auditory system, which is defined as central presbycusis, can impair sound localization and speech perception. Research has shown that oxidative stress plays a central role in the pathological process of central presbycusis. Thioredoxin 2 (Trx2), one member of thioredoxin family, plays a key role in regulating the homeostasis of cellular reactive oxygen species and anti-apoptosis. The purpose of this study was to explore the association between Trx2 and the phenotype of central presbycusis using a mimetic aging animal model induced by long-term exposure to d-galactose (d-Gal). We also explored changes in thioredoxin-interacting protein (TXNIP), apoptosis signal regulating kinase 1 (ASK1) and phosphorylated ASK1 (p-ASK1) expression, as well as the Trx2-TXNIP/Trx2-ASK1 binding complex in the auditory cortex of mimetic aging rats. Our results demonstrate that, compared with control groups, the levels of Trx2 and Trx2-ASK1 binding complex were significantly reduced, whereas TXNIP, ASK1 p-ASK1 expression, and Trx2-TXNIP binding complex were significantly increased in the auditory cortex of the mimetic aging groups. Our results indicated that changes in Trx2 and the TXNIP-Trx2-ASK1 signal pathway may participate in the pathogenesis of central presbycusis.

Bioavailability comparison of a new form of vilazodone XVII to IV in beagles using liquid chromatography/mass spectrometry.

Vilazodone hydrochloride (CAS 163521-12-8) is polymorphic and has 15 crystal forms, referred to as I-XI and XIII-XVI. In the study, we prepared and performed structural identification of a new crystal form named XVII. To investigate this in vivo, a rapid and sensitive method based on liquid-liquid extraction, followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed and validated for the determination of vilazodone hydrochloride in dog plasma. This HPLC-MS/MS method was successfully applied to a bioavailability comparison of two crystal forms of vilazodone hydrochloride (IV and XVII) in six healthy beagles using a single-dose, two-way crossover design. The maximum plasma concentration (C(max)), the time taken to reach C(max), and the area under the concentration-time curve were determined following oral administration of 10 mg vilazodone hydrochloride (IV or XVII) to beagles. These analyses revealed no significant bioavailability differences between vilazodone hydrochloride forms IV and XVII in dogs.