The aim of this study is to determine whether the c-Jun N-terminal kinase (JNK) signaling is a regulator of oxidative DNA damage, germ cell apoptosis (GCA), and mitochondrial dysfunction during testicular ischemia reperfusion injury (tIRI) using the JNK inhibitor SP600125. Male Sprague Dawley rats (n = 36) were equally divided into three groups: sham, tIRI only, and tIRI + SP600125 (15 mg/kg). Testicular ischemia was induced for 1 h followed by 4 h of reperfusion prior to animal sacrifice. Spermatogenesis was evaluated by light microscopy, while expression of oxidative stress and GCA-related mRNAs and proteins were evaluated by real-time polymerase chain reaction and colorimetric assays, respectively. Expressions of JNK, p53, and survivin were detected by immunofluorescence (IF) staining. Indicators of mitochondrial dysfunction were examined by western blot analysis and colorimetric assay. In comparison to sham, the tIRI testes showed a significant increase in lipid and protein oxidation products. Oxidative DNA damage was reflected by a significant increase in the number of DNA strand breaks, increased concentration of 8-OHdG, and elevated poly (ADP-ribose) polymerase activity. Spermatogenic damage was associated with the activation of caspase 3 and elevated Bax to Bcl2 ratio. This was also accompanied by a significantly heightened IF expression of the phosphorylated forms of JNK and p53 paralled with the suppression of survivin. Mitochondrial dysfunction was reflected by NAD⁺ depletion, overexpression of uncoupling protein 2, and increased level of cytochrome c. Such tIRI-induced modulations were all attenuated by SP600125 treatment prior to reperfusion. In conclusion, JNK signaling regulates oxidative DNA damage, GCA, and mitochondrial dysfunction through activation of p53 and suppression of survivin during tIRI.

中文翻译：

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JNK抑制可减轻睾丸缺血再灌注损伤中的氧化DNA损伤，生殖细胞凋亡和线粒体功能障碍。

这项研究的目的是确定使用JNK的c-Jun N末端激酶（JNK）信号是否是睾丸缺血再灌注损伤（tIRI）期间氧化DNA损伤，生殖细胞凋亡（GCA）和线粒体功能障碍的调节剂。抑制剂SP600125。雄性Sprague Dawley大鼠（n = 36）分为三组：假手术，仅tIRI和tIRI + SP600125（15 mg / kg）。在处死动物之前，先诱导睾丸局部缺血1小时，然后再灌注4小时。通过光学显微镜评估精子发生，同时通过实时聚合酶链反应和比色法评估氧化应激和GCA相关的mRNA和蛋白质的表达。通过免疫荧光（IF）染色检测JNK，p53和survivin的表达。通过蛋白质印迹分析和比色测定法检查线粒体功能障碍的指标。与假手术相比，tIRI睾丸显示脂质和蛋白质氧化产物显着增加。DNA链断裂数量的显着增加，8-OHdG浓度的增加，和提高的聚（ADP-核糖）聚合酶活性。生精损伤与胱天蛋白酶3的活化和升高的Bax与Bcl2的比例有关。这还伴随着JNK和p53磷酸化形式的IF表达的显着升高，这与survivin的抑制平行。NAD反映线粒体功能障碍⁺耗竭，解偶联蛋白2的过表达和细胞色素c的水平升高。在再灌注之前，这些tIRI诱导的调节均通过SP600125处理减弱。总之，JNK信号传导通过在tIRI期间激活p53和抑制survivin来调节氧化性DNA损伤，GCA和线粒体功能障碍。