シスプラチン誘発性難聴に対する注射用治療薬の神経細胞モデルを用いた予備的評価

Though ototoxic, cisplatin is a mainstay of chemotherapy for a variety of cancers. One suggested mechanism of cisplatin ototoxicity involves damage to the spiral ganglion afferent neurons in the inner ear. There is a need for a high-throughput model to screen medications for efficacy against cisplatin and to develop a local therapeutic to mitigate cisplatin's debilitating side effects. Microparticles encapsulating a therapeutic medication are an injectable and tunable method of sustained drug delivery, and thus a promising treatment.

SH-SY5y human neuroblastoma cells were used as a cell line model for the spiral ganglion neurons. The cells were dosed with cisplatin and four potential therapeutics (melatonin, metformin, cyclosporine, and N-acetylcysteine), with cell viability measured by CCK-8 assay. The most promising therapeutic, N-acetylcysteine (NAC), was then encapsulated into multiple poly(lactic-co-glycolic acid) (PLGA) microparticle subtypes of varied lactide-glycolide (L:G) ratios and NAC amounts. The elution profile of each microparticle subtype was determined over two months.

Of the therapeutics screened, only cells dosed with 1 or 10 mM NAC prior to cisplatin injury demonstrated an improvement in cell viability (73.8%, p < 1 × 10^-8) when compared to cells dosed with cisplatin alone. The 75:25 L:G microparticles demonstrated an increase in the amount of NAC released compared to the 50:50 L:G microparticles.

NAC is a potential therapeutic agent for cisplatin toxicity when tested in a neuronal cell line model. NAC was encapsulated into PLGA microparticles and eluted detectable concentrations of NAC for 6 days, which is a first step towards otoprotection for the weeks long duration of chemotherapy treatment. This work describes a method of screening potential therapeutics and a strategy to develop local drug eluting treatments to protect against cisplatin ototoxicity.