METHODS: Central chemoreflex drive and breathing function were assessed in freely moving heterozygous SOD2 knockout mice (SOD2+/- mice) and age-matched control wild type (WT) mice by whole-body plethysmography. O2.- levels were determined in RTN brainstem sections and brain isolated mitochondria, while SOD2 protein expression and tissue localization were determined by immunoblot, RNAseq and immunofluorescent staining, respectively.
RESULTS: Our results showed that SOD2+/- mice displayed reductions in SOD2 levels and high O2.- formation and mitochondrial dysfunction within the RTN compared to WT. Additionally, SOD2+/- mice displayed a heightened ventilatory response to hypercapnia and exhibited overt signs of altered breathing patterns. Both, RNAseq analysis and immunofluorescence co-localization studies showed that SOD2 expression was confined to RTN astrocytes but not to RTN chemoreceptor neurons. Finally, we found that SOD2+/- mice displayed alterations in RTN astrocyte morphology compared to RTN astrocytes from WT mice.
UNASSIGNED: These findings provide first evidence of the role of SOD2 in the regulation of O2.- levels in the RTN and its potential contribution on the regulation of central chemoreflex function. Our results suggest that reductions in the expression of SOD2 in the brain may contribute to increase O2.- levels in the RTN being the outcome a chronic surge in central chemoreflex drive and the development/maintenance of altered breathing patterns. Overall, dysregulation of SOD2 and the resulting increase in O2.- levels in brainstem respiratory areas can disrupt normal respiratory control mechanisms and contribute to breathing dysfunction seen in certain disease conditions characterized by high oxidative stress.
方法:通过全身体积描记术在自由移动的杂合子SOD2敲除小鼠(SOD2+/-小鼠)和年龄匹配的对照野生型(WT)小鼠中评估中枢化学反射驱动和呼吸功能。O2.-在RTN脑干切片和大脑分离的线粒体中确定水平,免疫印迹法测定SOD2蛋白表达和组织定位,RNAseq和免疫荧光染色,分别。
结果:我们的结果表明,SOD2+/-小鼠表现出SOD2水平降低和高O2。-与WT相比,RTN内的形成和线粒体功能障碍。此外,SOD2/-小鼠对高碳酸血症表现出增强的通气反应,并表现出明显的呼吸模式改变的迹象。两者,RNAseq分析和免疫荧光共定位研究表明,SOD2的表达仅限于RTN星形胶质细胞,而不限于RTN化学感受器神经元。最后,我们发现,与WT小鼠的RTN星形胶质细胞相比,SOD2+/-小鼠显示出RTN星形胶质细胞形态的改变.
■这些发现为SOD2在调节O2中的作用提供了第一个证据。-RTN中的水平及其对中枢化学反射功能调节的潜在贡献。我们的结果表明,脑中SOD2表达的减少可能有助于增加O2。-RTN中的水平是中枢化学反射驱动的慢性激增和改变的呼吸模式的发展/维持的结果。总的来说,SOD2的失调和由此导致的O2增加。-脑干呼吸区域中的水平可以破坏正常的呼吸控制机制,并导致在以高氧化应激为特征的某些疾病中看到的呼吸功能障碍。