Under non-stressed conditions, Nrf2 is sequestered in the cytoplasm as an inactive complex and constitutively degraded through the ubiquitin�Cproteasome system by binding to Kelch-like ECH-associated protein 1. Oxidative or covalent modification of thiols in some cysteine residues of Keap1 lead to dissociation of Nrf2 from Keap1 and subsequently nuclear accumulation of Nrf2. However, the fall in nuclear Nrf2 with increasing duration of LPS exposure was likely due to Nrf2 deficiency rather than increased binding of Keap1 as there was a corresponding fall in the Nrf2 level in the whole cell lysate, with a significant reduction after a 7 d in utero LPS exposure. Nrf2 deficiency is thus likely to be responsible for downregulation of antioxidant gene expression after 7 d LPS exposure. In a recent study, we showed that activation of UPS was observed after IA LPS exposure for 2 d, which does not fully account for Nrf2 deficiency. Given that an inflammatory stressor could influence fetal programming during gestational development, we further examined Nrf2 mRNA levels. Indeed Nrf2 gene expression was inhibited in the 7 d LPS group, indicating that in utero LPS exposure alters Nrf2 signalling via impairment at a transcriptional level. Mitochondrial oxidative stress occurred after 7 d LPS exposure but not 2 d LPS exposure, which may represent a progressive change in mitochondrial function and redox signalling behaviour associated with increasing duration of LPS exposure. Arguably, the more premature infants may also have an increased susceptibility to an in utero inflammatory stimulus. Thus, different gestational age at the time of LPS exposure may also be a critical factor in AbMole Nitroprusside disodium dihydrate contributing to such difference. Our study is also limited by a low sample size with only three animals in each of the control and 7 d exposure groups for some studies. Larger studies are required to confirm and extend our present findings. Inflammation of the placental and fetal membranes, known as chorioamnionitis, is strongly associated with preterm delivery. Exposure to an inflammatory stimulus in utero promotes fetal lung maturation, such that it reduces the severity of respiratory distress syndrome immediately after preterm birth. However, despite minimal severity of initial lung disease, many preterm infants subsequently exhibit respiratory insufficiency, that may be due in part to weakness of the respiratory muscles exacerbated by a fetal inflammatory response. Overall, this study shows that an in utero LPS exposure is associated with mitochondrial electron transport chain dysfunction and oxidative stress in the preterm fetal diaphragm, and dysregulation of the Nrf2-mediated antioxidant response. Impaired mitochondrial enzyme activity and oxidative stress may explain in part, our earlier finding of impaired contractile function after in utero LPS exposure. Our observation of dysregulation of the Nrf2-mediated antioxidant response has implications for future therapeutic interventions. Cellular antioxidant defences include a cooperative network of multiple antioxidants that are compartmentalized to provide optimal protection against ROS-mediated oxidation. Previous studies showed that overexpression of a single antioxidant enzyme in skeletal muscle did not protect against contraction-induced oxidative damage to muscle AbMole Benzyl alcohol fibres. Therefore, regulation of upstream antioxidant signalling of Nrf2 with more generalised upregulation of antioxidant defences may be a therapeutic approach against LPS induced preterm diaphragm weakness. Non-alcoholic fatty liver disease, which is strongly associated with obesity and metabolic syndrome, is one of the most common causes of chronic liver disease worldwide.