Redox Imaging of lung inflammation in mice

[0507] Female headstart in key factors responsible for mitochondrial functioning as a protective mechanism towards hyperoxia oxidative injury A. Saric*, S. Sobocanec, T. Balog, M. Popovic Hadzija, B. Kusic, T. Marotti et al Rudjer Boskovic Institute, Croatia It is known that mitochondria are a critical target of oxidative injury and exhibit altered redox potentials resulting in activation of cell death pathways. However, not much is known about sex-related mitochondrial status in hyperoxia oxidative condititons. Here, we observed greater female survival compared to males (95% vs. 63%, respectively) after exposing 4months old CBA mice to pure oxygen for 48 horus. Next, we investigated several parameters involved in acute oxidative stress conditions: DNA damage, TBARS and carbonyl levels were found to be significantly increased only in males following hyperoxia treatment. Greater levels of protective parameters (eNOS and Sirt1) found in control females could represent better female headstart in resistance to oxidative stress conditions. Moreover, MnSOD protein was found to be induced upon hyperoxia only in females, giving them the additional protection. We also investigated the role of apoptosis in tolerance to hyperoxia and found the association of greater resistance to oxygen and mitochondria-mediated apoptosis, as observed by degradation of proactive caspase 9 and caspase 3 forms in females. The work is now in progress to test the hypothesis that a key component of protective response to hyperoxia in females is occurring by estrogen regulation of eNOS and Sirt1 and consequent improved mitochondrial biogenesis, oxidative phosphorylation and metabolism in females compared to males. Keywords: hyperoxia, mitochondria, apoptosis, sexrelated doi:10.1016/j.freeradbiomed.2012.08.467 [0540] Redox Imaging of lung inflammation in mice K. Ichikawa*1, S. Sato1, T. Naganuma2, K. Yasukawa1, H. Utsumi1 1 Kyushu University, Japan, 2Japan Redox Inc., Japan Pneumonia is initiated by virus infection, inhalation to ozone, diesel exhaust particles etc. Water content in lung is low and the pneumonia is imaged by MRI technique only after severe inflammation occurred. Since

pneumonia is an oxidative diseases propagated by inflammatory cells, in vivo redox status changed in the diseases. In current study, we imaged a lung redox status of LPS-induced mouse using Overhauser enhanced MRI (OMRI) / nitroxyl spin probe technique. OMRI is a new technique for imaging free radicals / redox status in animals based on the Overhauser effect. Female Balbc mouse was intratracheally injected with 50 μg of LPS. The redox status of the mouse was measured 3, 6, 9 and 12 hours after the instillation. Carbamoyl or carboxy PROXYL was injected intratrachealy or intravenously to obtain OMRI images. The lung redox map was successfully obtained using OMRI technique for the first time. In the case of Carbamoy PROXYL, redox status at trachea domain changed significantly 3 hours after LPS-injection, while it took 6 hours until significant redox change was observed at venous domain. In the case of Carboxy PROXYL, no redox status changed at trachea domain, and significant changes were observed after 9 hours at venous domain. Current result clearly showed the propagation of LPSinduced inflammation from bronchial area to alveolocapillary domain. Keywords: redox, OMRI, reactive oxygen species doi:10.1016/j.freeradbiomed.2012.08.468 [0544] In vivo detection of myeloperoxidase activity by LC/MS analysis of 2-chloro-ethidium, a novel product formed from the reaction of hydroethidine with hypochlorous acid and chloramines G.J. Maghzal1, K. Cergol2, C. Suarna1, D. Newington1, A.J. Kettle3, R.J. Payne2, R. Stocker*1 et al 1 Centre for Vascular Research, School of Medical Sciences (Pathology) and Bosch Institute, University of Sydney, Australia, 2School of Chemistry, University of Sydney, Australia, 3Free Radical Research Group, Department of Pathology, University of Otago, New Zealand Hypochlorous acid (HOCl) is a strong 2-electron oxidant produced by myeloperoxidase (MPO) expressed predominantly in neutrophils that can damage biomolecules and deplete antioxidants either directly or through secondary reactions via chloramines. MPOderived oxidants are thought to contribute to atherosclerosis and related vascular diseases via multiple mechanisms including the oxidative inactivation of endothelial nitric oxide synthase, inhibition of reverse cholesterol transport by HDL, and foam cell formation by LDL. Indeed, MPO and HOCl-modified LDL and HDL are present in human atherosclerotic plaques. In vivo

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