Objective:To study whether cisplatin may induce apoptosis in the pericytes of cochlear stria vascularis and underlying mechanisms.Methods:Twenty male C57BL/6J mice aged 6-8 weeks were divided into control group and a cisplatin group. Primary cultured mouse cochlear vascular peristriatal cells were identified and divided into control group, cisplatin group, and N-acetylcysteine+cisplatin group. Auditory brainstem response (ABR) was used to detect hearing in mice. Hematoxylin eosin (HE) staining was used to observe morphological changes in the stria vascularis of the cochlea. The total superoxide dismutase (SOD) activity test kit (WST-1 method) and thiobarbituric acid (TBA) method were used to detect SOD activity and Malondialdehyde (MDA) content, respectively. DCFH-DA fluorescence probe was used to detect the content of reactive oxygen species in peripheral cells. Hoechst 33 342 and flow cytometry were used to detect the apoptosis rate of pericytes. Immunofluorescence technology was used to detect the distribution and expression of apoptosis related proteins in pericytes of cochlear stria vascularis. Immunohistochemistry and Western blotting (WB) were used to detect the expression of apoptosis-and mitochondrial-related proteins. Mito SOX TM-red and JC-1 were used to detect the mitochondrial function of pericytes. Evans blue staining was used to observe the permeability of the blood labyrinth barrier (BLB). Statistical analysis was conducted using SPSS 18.0 software. Results:Compared with the control group, the cisplatin group significantly increased in the hearing threshold ( t=4.72, P<0.01), Ⅰ-wave latency ( t=12.25, P<0.05), and the levels of oxidative stress in the cochlea and pericytes ( t=38.34, P<0.01), and also cisplatin caused disorder and contraction of the cochlear stria vascularis structure, increased BLB permeability [Evans blue leakage (1.08±0.42) AU vs (0.55±0.23) AU, t=4.64, P<0.05], with a statistically significant difference, enhanced the expressions of apoptotic proteins c-Caspase-3 ( t=5.01, P<0.01) and Bax ( t=6.33, P<0.01) in the peristriatal cells of cochlear blood vessels in mice treated with cisplatin increased. And cisplatin can induce apoptosis of primary cultured pericytes and up-regulate the expression of c-Caspase-3 and Bax ( P<0.05). The NAC+cisplatin group partially reversed cisplatin-induced pericyte apoptosis ( P<0.05). Cisplatin caused damage to the mitochondrial function of peripheral cells, and induced the release of apoptosis-inducing factor (AIF) and cytochrome C (cyt-c) into the cytoplasm ( P<0.05). The NAC+cisplatin group partially reversed cisplatin induced pericyte apoptosis ( P<0.05) and mitochondrial damage ( P<0.05). Conclusion:Cisplatin can increase the level of oxidative stress in the cochlea and cause mitochondrial pathway apoptosis in C57BL/6J mouse cochlear vascular peristriatal cells.