What is the impact of the platinum nanoparticles on the cell viability of the mouse organ of Corti cell line (HEI-OC1) and the rat spiral ganglion neurons (SGN)?

Introduction So far, systemic application of cortisone and antibiotics are not able to recover CI-patients from increased impedances. Recent studies revealed corroded platinum electrode contacts which may cause the reduced speech perception. Aim of this study is the characterisation of the effects of platinum nanoparticles (Pt-NP, 3 nm) on HEI-OC1 cells and rat primary SGN.Methods The metabolic activity of the HEI-OC1 cells was determined at 50-150 µg/ml Pt-NP by using resazurine. The SGN were dissociated from the cochleae of postnatal rats (P5) and cultivated for 48 h following exposition to 20-100 µg/ml Pt-NP. The SGN survival rate and neurite outgrowth were quantified by staining of the neurofilament antigene. Also, scanning (SEM) and transmission electron microscopy (TEM) were used to examine morphological and ultrastructural changes.Results 75 and 150 µg/ml of the Pt-NP reduced the metabolic activity of the HEI-OC1 cells without demonstrating cytotoxic effects. However, TEM demonstrated not only apoptosis at 100 µg/ml Pt-NP, but also induction of repair processes by means of autophagosomale-lysosomale mechanisms. Neither SGN loss nor reduction of the neurite outgrowth was found at any Pt-NP concentration.Conclusions From 75 µg/ml up Pt-NP decreased the mitochondrial activities, but did not induce cell death. Accordingly, TEM revealed effective repair mechanisms in the HEI-OC1 cells in response to Pt-NP exposure. In contrast, Pt-NP had no effects on the metabolic activities of the SGN. Thus, it has to be elucitated if SGN and glial cells exposed to Pt-NP for longer cultivation period may undergo cell death.

Publication History

Article published online:
24 May 2022