Abstract

HYPOTHESIS Erythropoietin (EPO) may protect against cisplatin-induced ototoxicity in HEI-OC1 auditory cell line. BACKGROUND Cisplatin is a widely used chemotherapeutic agent for the treatment of human solid tumors limited by its high incidence of ototoxicity. Currently, there are no clinical solutions. EPO has been reported to have varieties of neuroprotective effects. However, nothing has yet been reported on its potential to prevent cisplatin ototoxicity in auditory cell lines and possible mechanism. METHODS HEI-OC1 cells were incubated with 20 μM of cisplatin for 48 hours, after application of various concentrations of EPO for 24 hours. Cell viability was determined using a Cell Counting Kit-8 (CCK-8) assay. Oxidative stress and apoptosis were assessed by reactive oxygen species (ROS) measurement, Hoechst 33258 staining, and flow cytometry (FC). Western blot (WB) and real-time quantitative PCR were used to detect nuclear factor erythroid 2-related factor 2 (Nrf2), NAD (P)H quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), Bcl-2 and Bcl-xl protein and mRNA expression levels. RESULTS Pretreatment with 40, 8, and 1.6 ng/mL of EPO for 24 hours before application of 20 μM cisplatin increased cell viability in HEI-OC1 cells. Besides, EPO enhanced the expression of Nrf-2, HO-1, and NQO1. Moreover, upregulation of the expression of Bcl-2 and bcl-xl were also observed. CONCLUSION Our results suggest that EPO alleviates cisplatin-induced ototoxicity by activating Nrf2-ARE signaling.