Detection of single-stranded DNA (ssDNA) in the vestibule of guinea pigs after the application of cisplatinum (CDDP).
BACKGROUND
Cisplatinum (CDDP) has a toxic effect on the inner ear. CDDP reacts with DNA and leads to apoptotic cell death. In this study, the presence of single-stranded DNA (ssDNA) was examined immunohistochemically.


METHODS
CDDP (10 mg/kg b.w.) was injected into the guinea pigs intra-peritoneally. Animals were sacrificed three days after the injection. The temporal bones were fixed via cardiac infusion. The tissues were embedded in paraffin and then used for immunohistochemical examination.


RESULTS
That ssDNA was detected in the CDDP treated vestibule. The sensory epithelium, transitional area, dark cells and vestibular ganglion cells exhibited a positive immunoreactivity to ssDNA.


CONCLUSIONS
DNA fragmentation is a characteristic feature of apoptosis. Fragmented DNA is detected as ssDNA. Our results indicate that CDDP involves the apoptosis in the inner ear and this is the cause of the ototoxicity of CDDP.
Watanabe
K
K
Department of Oto-Rhino-Laryngology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan. bxp02646@nifty.ne.jp
Jinnouchi
K
K
Yagi
T
T
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002945:Cisplatin / Q000494:pharmacology*; D004277:DNA, Single-Stranded / Q000032:analysis*; D006168:Guinea Pigs; D007124:Immunoenzyme Techniques; D014722:Vestibule, Labyrinth / Q000187:drug effects* / Q000473:pathology
D000970:Antineoplastic Agents; D004277:DNA, Single-Stranded; D002945:Cisplatin