Up-regulation thioredoxin contributes to inhibite diabetic hearing impairment

Abstract

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia. An association between DM and hearing impairment has been widely discussed. It’s essential to find effective prevetion or diagnosis of diabetic hearing loss. Thioredoxin (Trx) is a small molecule protein (12kDa) and plays biological functions such as anti-apoptotic, transcriptional regulation. In this study, our aim is to clarify the protective effect of Trx on diabetic hearing loss to find the early potential therapeutic target of diabetic hearing impairment in clinic in the future. Trx transgenic(Tg) mice was used to induce diabetic model by intraperitoneal injected Streptozotocin (STZ) and with/without SF or PX12 treatment. Succinate Dehydrogenase (SDH) Staining was used to evaluate the loss of hair cells. The relative expression of related proteins and genes was detected by Western blot and qRT-PCR. In diabetic mice, the outer hair cells were lost significantly. However, the loss of hair cells was delayed over-expression Trx. Moreover, the expression of PGC-1α, bcl-2 and LC3 was increased in Tg(+)-DM mice compared with Tg(-)-DM mice. The expression of ASK1, Txnip, GRP78, CHOP and p62 was decreased in Tg(+)-DM mice compared with Tg(-)-DM mice. Taken together, up-regulation Trx can protect cochlear hair cell from damage in diabetes. The underlying mechanism may be related to regulate ER stress through ASK1 and mitochondria pathway or autophagy via Txnip.