Background

Excess mitochondrial reactive oxygen species (mROS) in sepsis is associated with organ failure, in part by generating inflammation through the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome. We determined the impact of a mitochondrial-targeted antioxidant (MitoTEMPO) on mitochondrial dysfunction in renal proximal tubular epithelial cells, peritoneal immune cell function ex vivo, and organ dysfunction in a rat model of sepsis.

Methods

The effects of MitoTEMPO were assessed ex vivo using adenosine triphosphate and lipopolysaccharide-stimulated rat peritoneal immune cells and fresh rat kidney slices exposed to serum from septic rats. We assessed mROS production and phagocytotic capacity (flow cytometry), mitochondrial functionality (multiphoton imaging, respirometry), and NLRP3 inflammasome activation in cell culture. The effect of MitoTEMPO on organ dysfunction was evaluated in a rat model of faecal peritonitis.

Results

MitoTEMPO decreased septic serum-induced mROS (P<0.001) and maintained normal reduced nicotinamide adenine dinucleotide redox state (P=0.02) and mitochondrial membrane potential (P<0.001) in renal proximal tubular epithelial cells ex vivo. In lipopolysaccharide-stimulated peritoneal immune cells, MitoTEMPO abrogated the increase in mROS (P=0.006) and interleukin-1β (IL-1β) (P=0.03) without affecting non-mitochondrial oxygen consumption or the phagocytotic-induced respiratory burst (P>0.05). In vivo, compared with untreated septic animals, MitoTEMPO reduced systemic IL-1β (P=0.01), reduced renal oxidative stress as determined by urine isoprostane levels (P=0.04), and ameliorated renal dysfunction (reduced serum urea (P<0.001) and creatinine (P=0.05).

Conclusions

Reduction of mROS by a mitochondria-targeted antioxidant reduced IL-1β, and protected mitochondrial, cellular, and organ functionality after septic insults.

中文翻译：

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选择性线粒体抗氧化剂 MitoTEMPO 可减轻大鼠实验性脓毒症的肾功能障碍和全身炎症

背景

脓毒症中过量的线粒体活性氧 (mROS) 与器官衰竭有关，部分原因是通过含有 NOD、LRR 和 pyrin 结构域的蛋白 3 (NLRP3) 炎性体产生炎症。我们在脓毒症大鼠模型中确定了线粒体靶向抗氧化剂 (MitoTEMPO) 对肾近端肾小管上皮细胞线粒体功能障碍、离体腹膜免疫细胞功能和器官功能障碍的影响。

方法

使用三磷酸腺苷和脂多糖刺激的大鼠腹膜免疫细胞和暴露于脓毒症大鼠血清的新鲜大鼠肾切片离体评估 MitoTEMPO 的作用。我们评估了细胞培养中 mROS 的产生和吞噬能力（流式细胞术）、线粒体功能（多光子成像、呼吸测量）和 NLRP3 炎性体激活。在粪便腹膜炎大鼠模型中评估了 MitoTEMPO 对器官功能障碍的影响。

结果

MitoTEMPO 在离体肾近端肾小管上皮细胞中降低脓毒症血清诱导的 mROS ( P <0.001) 并维持正常降低的烟酰胺腺嘌呤二核苷酸氧化还原状态 ( P = 0.02) 和线粒体膜电位 ( P <0.001) 。在脂多糖刺激的腹膜免疫细胞中，MitoTEMPO 消除了 mROS ( P =0.006) 和白细胞介素-1β (IL-1β) ( P =0.03) 的增加，而不影响非线粒体耗氧量或吞噬细胞诱导的呼吸爆发 ( P > 0.05) 。在体内，与未经治疗的脓毒症动物相比，MitoTEMPO 降低了全身性 IL-1β ( P=0.01），减少由尿异前列腺素水平确定的肾脏氧化应激（P = 0.04），并改善肾功能障碍（降低血清尿素（P <0.001）和肌酐（P = 0.05）。

结论

线粒体靶向抗氧化剂减少 mROS 会降低 IL-1β，并在脓毒症损伤后保护线粒体、细胞和器官功能。