Protective effects of two novel nitronyl nitroxide radicals on heart failure induced by hypobaric hypoxia.

Hypobaric hypoxia (HH), linked to oxidative stress, impairs cardiac function. We synthesized a novel nitronyl nitroxide radical, an HPN derivative (HEPN) and investigated the protective effects of HEPN and HPN against HH-induced heart injury in mice and the underlying mechanisms of action. Mice were administered with HPN (200 mg/kg) or HEPN (200 mg/kg) 30 min before exposed to HH. The cardiac function was measured. Serum AST, CK, LDH and cTnI were estimated. Heart tissue oxidase activity, SOD, CAT, GSH-Px, ROS and MDA were estimated. ATP content, Na+/K+-ATPase and Ca2+/Mg2+-ATPase activity was measured. The expression of HIF-1, VEGF, Nrf2, HO-1, Bax, Bcl-2, Caspase-3 was estimated. Results showed that pretreatment with HEPN or HPN led to a dramatic decrease in the activity of biochemical markers AST, CK, LDH and cTnI in murine serum. They increased the activity of SOD, CAT and GSH-Px and reduced the level of ROS and MDA in the hearts of mice. HEPN and HPN could increase the expression of Nrf2 and OH-1. They could maintain the ATPase activity. The Bax and Caspase-3 expression as well as the ratio of Bax/Bcl-2 were significantly downregulated and the Bcl-2 expression was upregulated by HPN or HEPN compared to the HH group. They may attenuate the HH-induced oxidant stress via free radical scavenging activity. The present study showed that the nitronyl nitroxide radical HEPN and HPN may be potential therapeutic agents for treatment of HH-induced cardiac dysfunction.

Jing L ，Shao J ，Sun W ，Lan T ，Jia Z ，Ma H ，Wang H ... -  《-》

Protective effect of nitronyl nitroxide against hypoxia-induced damage in PC12 cells.

Luo H ，Sun W ，Shao J ，Ma H ，Jia Z ，Jing L ... -  《-》

A novel nitronyl nitroxide radical HPN-C(6) attenuates brain damage in an acute hypobaric hypoxia mouse model through inhibition of the oxidative stress.

Hypobaric hypoxia (HH) results in the increased formation of ROS and induces a wide range of deleterious effects on the brain. Nitronyl nitroxide radicals are a kind of stable organic nitroxide radicals with a good ability to scavenge ROS. Herein, a series of new nitronyl nitroxide radicals was synthesized according to the previous method. Among them, a compound with six carbon atoms alkyl chain (HPN-C6) was screened for estimating the protective effect against HH-induced brain injury in the acute HH mouse model. The results showed that HPN-C6 ameliorated oxidative stress by decreasing the activity of LDH and the content of H2O2, NO, and MDA, increasing the activities of SOD, CAT and GSH-PX in the brain tissue of HH injured mice. Moreover, HPN-C6 exhibited an anti-inflammatory effect by reducing the level of IL-1β, TNF-α, and IL-6 in the brains of mice after HH exposure through regulating the P38 MAPK signaling pathway. In addition, HPN-C6 exhibited the protection effect by inhibiting the release of mitochondrial cytochrome C, locking the activation of caspase-3, and downregulating the expression of Bax and upregulating the expression of Bcl-2. HPN-C6 pretreatment could inhibit the caspase-dependent mitochondria apoptosis pathway. These findings indicate that HPN-C6 is a potential therapeutic agent to prevent brain damage induced by HH.

Jing L ，Huang Y ，Ma H ，Wang H ... -  《-》

Nitronyl Nitroxide Ameliorates Hypobaric Hypoxia-Induced Cognitive Impairment in Mice by Suppressing the Oxidative Stress, Inflammatory Response and Apoptosis.

Jing L ，Da Q ，Zhang S ，Zhang J ，Ma H ，Luo H ... -  《-》

The antioxidative effect of a novel free radical scavenger 4'-hydroxyl-2-substituted phenylnitronyl nitroxide in acute high-altitude hypoxia mice.

Fan PC ，Ma HP ，Jing LL ，Li L ，Jia ZP ... -  《-》