CISPLATIN-INDUCED CHANGES IN THE NUMBER OF ARGYROPHILIC NUCLEOLAR GRANULES IN CULTURED CHICK DORSAL-ROOT GANGLION NEURONS

Changes in the number of argyrophilic nucleolar granules (ANGs) caused by cisplatin treatment were studied in sensory neurons isolated from dorsal root ganglia of 12-day-old chick embryos. The number of ANGs ch anged during culture in untreated cultures. The mean number of ANGs pe r cell was 10.6 +/- 4.6 at 24 h. A dramatic increase of ANGs (mean num ber 32.8 +/- 6.7) was observed after 48 h in vitro, followed by a slig ht decrease to 26.8 +/- 0.3 at 72 h. Cisplatin treatment caused a sign ificant decrease of the number of ANGs per neuron depending on the con centration of the drug in culture medium as well as on the exposure ti me. The profile of changes of ANGs within the time was at low concentr ations of cisplatin (1 and 2.5 mu g/ml) identical with untreated cultu res. The mean number of ANGs was unchanged in the cells exposed for 24 h only and reduced in cultures treated for 48 and 72 h. At higher con centrations of cisplatin (from 5 to 20 mu g/ml), a prominent decrease of the mean number of ANGs was observed in all cultures in all time in tervals. These findings provide evidence that cisplatin influences the nucleolar organizer regions of dorsal root ganglia neurons. Thus, nuc leolar RNA and protein synthesis can be reduced. This alteration of ce ll metabolism probably contributes to the development of peripheral se nsory neuropathy.