Fig. 4

Cisplatin is retained in human cochleae long after cessation of treatment. a Platinum concentrations measured in cochlear sections of human temporal bones. Matched pairs of patients who received cisplatin chemotherapy and control (cisplatin-naive) patients are plotted by the time elapsed between the patient’s last cisplatin infusion and their death. Each data point represents an individual 20 µm cochlear section. Multiple two-tailed t-tests with correction for multiple comparisons by the Holm–Šidák method were used to determine significance. Data are expressed as mean ± s.e.m. *P < 0.05. b Representative brightfield image of a cochlear section prior to ICP-MS analysis. Similar sections were digested whole and analyzed for total cisplatin content. This section was laser ablated in the region outlined in red. Scale bar = 1 mm. c Laser ablation ICP-MS image of platinum distribution in the area in the red box in b from a patient who was treated with cisplatin. This patient died 25 days after their last cisplatin infusion. Green arrowhead marks stria vascularis, yellow arrowheads mark cochlear nerve fibers, white arrowheads mark the boundary between the cochlear nerve and the bone of the cochlear modiolus, white arrows mark the endosteum which lines the cochlear canal, asterisks mark surrounding cochlear bone, and white box frames organ of Corti. Scale bar = 500 µm. Platinum signal intensity values are in arbitrary units