Alterations in the stria vascularis in relation to cisplatin ototoxicity and recovery.
We have investigated whether or not cisplatin-induced depression of the endocochlear potential (EP), and its subsequent recovery, possesses a morphological correlate in the stria vascularis. Guinea pigs implanted with round window electrodes were treated daily with cisplatin (1.5 mg/kg/day) until the compound action potential showed a profound hearing loss (> or =40 dB at 8 kHz after 5-18 days). Animals were either sacrificed immediately after the shift in hearing threshold ('SHORT' group) or allowed to recover for > or =4 weeks and subsequently sacrificed ('LONG' group). Control animals ('CONTROL' group) were not treated with cisplatin. Using stereological methods we measured the total strial cross-sectional area together with the areas occupied by the different strial components: the marginal, intermediate and basal cells. The total strial cross-sectional area in the basal turn of the LONG group was found to be significantly smaller than that of the SHORT and the CONTROL groups, whereas the EP was normal in the LONG group (in comparison to the CONTROL group) and markedly decreased in the SHORT group. The smaller area in the LONG group was mainly due to a decrease in the area occupied by the intermediate cells and to a lesser extent to a decrease in the marginal cell area. The area occupied by the basal cells did not change. Thus, the marked decrease in EP after 5-18 days of cisplatin administration was not related to shrinkage of the stria vascularis. Moreover, 4 weeks later the EP showed full recovery, whereas the stria vascularis had shrunk markedly.
Hearing Research Laboratories, Department of Otorhinolaryngology, University Medical Center Utrecht, Room G.02.531, P.O. Box 85.500, 3508 GA Utrecht, The Netherlands.
Steven
S
Sluyter
Sjaak F L
SF
Klis
John C M J
JC
de Groot
Guido F
GF
Smoorenburg
D000200:Action Potentials / Q000187:drug effects; D019412:Anatomy, Cross-Sectional; D000818:Animals; D000970:Antineoplastic Agents / Q000506:poisoning*; D002945:Cisplatin / Q000506:poisoning*; D003051:Cochlea / Q000473:pathology / Q000503:physiopathology*; D004427:Ear Diseases / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology*; D004594:Electrophysiology; D005260:Female; D006168:Guinea Pigs; D034381:Hearing Loss / Q000139:chemically induced* / Q000503:physiopathology*; D008854:Microscopy, Electron; D020127:Recovery of Function; D013316:Stria Vascularis / Q000473:pathology*
D000970:Antineoplastic Agents; D002945:Cisplatin