Figure 1. Hair cell death is observed at 4 days after cisplatin treatment.

Mouse utricles were placed in organ culture, treated for 24 hr with 10 µM cisplatin, and then rinsed and maintained in cisplatin-free medium for an additional two or four days. Control utricles were cultured in parallel (i.e., for three or five days, total), but did not receive cisplatin. Specimens were then fixed and hair cells were immunolabeled for myosin VIIa (red). No evidence for hair cell injury was observed after three days in vitro, either in control utricles (A) or utricles treated with cisplatin (B). Quantification of hair cells in these specimens confirmed this observation (C). A small reduction in hair cell numbers was evident after five days culture in control medium (D). However, a considerable loss of hair cells was observed in utricles that were maintained for four days after cisplatin treatment (E, F, *p<0.005, t-test). CP=cisplatin-treated. Scale bar = 50 µm.