Aims: Preterm birth (PTB), recognized as delivery before 37 weeks of gestation, is a multifactorial syndrome characterizing as the main cause of neonatal mortality. Reactive oxygen species (ROS) have been identified as proinflammatory factors to cause placental inflammation, thereby resulting in several pregnancy outcomes. To date, limited knowledge regarding the underlying mechanisms of ROS-induced PTB has been reported. In this study, we aimed to investigate the role of oxidative stress in PTB and the protective effects of mitochondria-targeted antioxidant MitoTEMPO (MT) on preterm labor and offspring mice. Results: In this study, we found that preterm placentas had abnormal mitochondrial function, oxidative stress, and inflammatory response. In the lipopolysaccharide (LPS)-induced PTB mouse model, MT inhibited PTB by ameliorating maternal oxidative stress and inflammation, especially in placentas, thus improving placental function to maintain pregnancy. Antenatal administration of MT prevented LPS-induced fetal brain damage in acute phase and improved long-term neurodevelopmental impairments. Furthermore, our in vitro investigations validated that MT retarded the ROS accumulation and inflammatory response in LPS-stimulated trophoblast cells by promoting Kelch-like ECH-associated protein 1 (Keap1) degradation and subsequently activating nuclear factor erythroid 2-related factor 2 (Nrf2). By inhibiting Nrf2 activation, we discovered that the anti-inflammation and protective characteristics of MT were Nrf2/ARE pathway dependent. Innovation and Conclusion: MT inhibited PTB and fetal brain injury by inhibiting maternal inflammation and improving placental function through Keap1/Nrf2/antioxidant response element signaling pathway. Our findings provide a novel therapeutic strategy for PTB.
Keywords: Keap1/Nrf2; MitoTEMPO; fetal brain injury; inflammation; mitochondrial oxidative stress; preterm birth.