Comparison of Cytotoxic and Ototoxic Effects of Lipoplatin and Cisplatin in Neuroblastoma In Vivo Tumor Model

BACKGROUND: This study aimed to compare the cytotoxic, cytostatic, and ototoxic effects of lipoplatin compared to cisplatin application in the subcutaneous xenograft nude mouse neuroblastoma tumor model. METHODS: In this study, C1300 neuroblastoma cells were administered subcutaneously to 21 male nude mice. When the tumor reached 150 mm(3) diameter, mice were randomized into 3 groups. Saline, cisplatin, and lipoplatin were given intraperitoneally. The auditory function tests were performed before administration and 72 hours after administration. Mice were sacrificed and the tumor and cochlea were removed after 72 hours. Histopathologic evaluation of necrosis and apoptosis was determined by the TdT-mediated dUTP-biotin nick end labeling (TUNEL) method. Cyclooxygenase 2, superoxide dismutase 2, and inducible nitric oxide synthase levels were determined by immunohistochemistry in tissue samples. RESULTS: Apoptosis and necrosis rates were higher in lipoplatin group than in cisplatin group (P = .035 and P = .010, respectively) in tumor tissue. In the spiral ganglion, apoptosis and necrosis were lower in the lipoplatin group than in cisplatin group (P = .002 and P = .002, respectively). Cyclooxygenase 2 pattern in the cochlea was positive in both control and lipoplatin group and negative in cisplatin group (P = .001). Superoxide dismutase 2 and inducible nitric oxide synthase 2 protein expressions showed no difference between groups. The auditory functions were similar to baseline values and had a better threshold value in lipoplatin group than cisplatin group. CONCLUSION: For the treatment of neuroblastoma, the use of lipoplatin seems to be beneficial in reducing side effects of cisplatin. We recommend that the mechanism of these properties of lipoplatin should be evaluated in further studies.