目的：研究PPARγ激动剂15D-PGJ2对H2O2诱导的离体小鼠耳蜗螺旋神经节氧化损伤的防护作用。方法分离生后3-5 d的小鼠耳蜗基底膜,培养24 h后不同浓度PPARγ激动剂15D-PGJ2(10μM,30μM)预处理24h,再分别加入含有不同浓度H2O2(3mM,6mM)的培养基培养24小时。采用NF200免疫荧光染色方法行离体耳蜗基底膜螺旋神经纤维免疫荧光染色，在免疫荧光显微镜下观察各组螺旋神经纤维形态以及密度改变。结果3mM H202单独作用于原代培养的基底膜螺旋神经节24h时，螺旋神经纤维呈节断状损失改变,神经纤维逐渐变细局部断裂,染色变淡,神经纤维数量明显降低。随着H202浓度的增加，受损伤的螺旋神经微丝数目呈明显增加趋势。10μM 15D-PGJ2预处理24小时能提高H202损伤后基底膜螺旋神经纤维的数量。30μM 15D-PGJ2预处理组螺旋神经纤维数量明显增加。随着15D-PGJ2浓度提高,其保护作用加强。结论 PPARγ激动剂15D-PGJ2可减轻H2O2诱导的离体小鼠耳蜗基底膜螺旋神经节氧化损伤。%Objective To evaluate the protective effects by PPAR gamma agonist 15D-PGJ2 against hydrogen perox⁃ide (H2O2)-induced oxidative damage to auditory nerve fibers in an in vitro model. Method Cochlear basilar membranes from mice of postnatal day 3 were cultured for 24 h and subjected to 24 h treatment of H2O2 (3 mM, 6 mM), with or without 24 h pretreatment with various concentrations of PPAR gamma agonist 15D-PGJ2 (10μM, 30μM) and followed by H2O2 treat⁃ment for 24 h, respectively. Auditory nerve fibers from spiral ganglion neurons projecting to the organ of Corti were labeled with neurofilament-200 via immunohistochemistry and quantified for evaluation of surviving auditory nerve fibers. The data were statistically analyzed. Results The auditory nerve fibers from spiral ganglion neurons appeared normal in the control group. In contrast, intact nerve fibers were significantly reduced by H2O2 treatment in a dose dependent manner. When cochle⁃ar explants were pretreated with 15D-PGJ2 before H2O2 treatment for 24 h, surviving auditory nerve fibers were significantly increased, suggesting strengthened protective effects by increasing 15D-PGJ2 concentration against H2O2. Conclusion PPAR gamma agonist 15D-PGJ2 can protect auditory nerve fibers from spiral ganglion neurons against H2O2 damage in mice.
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