抗腫瘍剤(ナイトロミン,シスプラチン)による蝸牛障害とステロイドの影響

抄録

When anticancer drugs are used clinically, steroid hormone are combined commonly for prevention of the side effects. We studied the cochlear damage by anti-cancer drugs (Nitromin, Cisplatin) and the infuluence of steroid hormone against this damage, in guinea pigs. Now, we observed the cochlear damage by Nitromin or Cisplatin with or without steroid hormone. Nitromin was administered intracardially by one shot, while, Cisplatin was administered intraperitoneally for 5 days once a day. We measured Nitromin-concentration in cochlear emulsion, and Pt-concentration in cochlear emulsion and blood. This damage was also observed morphologically by sccanning electronmicroscopy and light microscopy.
The following interesting findings were obtained:
(1) As for the Nitromin-induced cochlear damage, it was observed mainly in outer hair cells, and it started at the lower basal turn in about 8 hours after administration of Nitromin. In case of the combined steroid hormone, the degree of this damage was more severely and broadly. However, it was impossible to measure the Nitromin-concentration in cochlear emulsion.
(2) As for the Cisplatin-induced cochlear damage, it was observed mainly in outer hair cells, too. The degree of this damage were not depended on Pt-concentration in blood, but in cochlear emulsion. Pt- concentration in blood with steroid hormone was more lower than that without steroid hormone. However, Pt-concentration in cochlear emulsion with steroid hormone was more higher than that without steroid hormone, in one hour after adminstration. But, the former was more lower than the latter, in 24 hours after administration. In case of the combined steroid hormone, the degree of this damage was more severely like a Nitromin-induced cochlear damage.
Therefore, steroid hormone would accelerate the drug-permeability into the cochlea when we conjectured this cause.