In this study, Zhan and colleagues dissected how cisplatin treatment affected the cochlea in mice. To do so, they extracted the cochlea from mice and moved them to laboratory dishes, where they added cisplatin and tracked how this affected hair cells.
What the Sun Yat-Sen University researchers found was that cisplatin caused the death of hair cells in a time- and concentration-dependent manner; that is, the toxicity of cisplatin increased with longer and more concentrated exposures. Cisplatin also caused dysfunction of mitochondria, important cell structures that take charge of vital functions like energy production and protection against oxidative stress — where harmful, oxygen-containing molecules accumulate.
Zhan and colleagues also looked at how NAD+ levels were correlated to cisplatin ototoxicity because NAD+ has emerged as a potential therapeutic molecular target in various diseases. Although small concentrations and short lengths of cisplatin treatment led to slight increases in NAD+ levels, the highest concentrations and longest treatments of cisplatin led to major decreases in NAD+ levels.