Prolonged use of nitric oxide donor sodium nitroprusside induces ocular hypertension in mice.

Nitric oxide (NO) donors are promising therapeutic candidates for treating intraocular hypertension (IOP) and glaucoma. This study aims to investigate the effect of prolonged use of NO donor sodium nitroprusside (SNP) on IOP. Since SNP has a short biological half-life, a nanoparticle drug delivery system (mesoporous silica nanoparticles) has been used to deliver SNP to the target tissues (trabecular meshwork and Schlemm's canal). We find that the sustained use of NO donor initially reduced IOP followed, surprisingly, by IOP elevation, which could not recover by drug withdraw but could be reversed by the antioxidant MnTMPyP application. The IOP elevation and normalization coincide with increased and reduced protein nitration in the mouse conventional outflow tissue. These findings suggest that the prolonged use of NO donor SNP may be problematic as it can cause outflow tissue damage by protein nitration. MnTMPyP is protective of the nitrative damage which could be considered to be co-applied with NO donors.

Neonatal glucocorticoid overexposure alters cardiovascular function in young adult horses in a sex-linked manner.

Prenatal glucocorticoid overexposure has been shown to programme adult cardiovascular function in a range of species, but much less is known about the long-term effects of neonatal glucocorticoid overexposure. In horses, prenatal maturation of the hypothalamus-pituitary-adrenal axis and the normal prepartum surge in fetal cortisol occur late in gestation compared to other precocious species. Cortisol levels continue to rise in the hours after birth of full-term foals and increase further in the subsequent days in premature, dysmature and maladapted foals. Thus, this study examined the adult cardiovascular consequences of neonatal cortisol overexposure induced by adrenocorticotropic hormone administration to full-term male and female pony foals. After catheterisation at 2-3 years of age, basal arterial blood pressures (BP) and heart rate were measured together with the responses to phenylephrine (PE) and sodium nitroprusside (SNP). These data were used to assess cardiac baroreflex sensitivity. Neonatal cortisol overexposure reduced both the pressor and bradycardic responses to PE in the young adult males, but not females. It also enhanced the initial hypotensive response to SNP, slowed recovery of BP after infusion and reduced the gain of the cardiac baroreflex in the females, but not males. Basal diastolic pressure and cardiac baroreflex sensitivity also differed with sex, irrespective of neonatal treatment. The results show that there is a window of susceptibility for glucocorticoid programming during the immediate neonatal period that alters cardiovascular function in young adult horses in a sex-linked manner.

Exacerbated Headache-Related Pain in the Single Prolonged Stress Preclinical Model of Post-traumatic Stress Disorder.

Chronic headache pain is one of the most commonly reported comorbid pain conditions with post-traumatic stress disorder (PTSD) patients and resistant to effective treatment, yet no combined preclinical model of the two disorders has been reported. Here, we used a modified chronic headache pain model to investigate the contribution of single prolonged stress (SPS) model of PTSD with sodium nitroprusside (SNP)-induced hyperalgesia. Injection of SNP (2 mg/kg, i.p.) occurred every other day from day 7 to day 15 after initiation of SPS in rats. Paw withdrawal threshold (PWT) to von Frey stimuli and tail flick latencies (TFL) dramatically decreased as early as 7 days after SPS and lasted until at least day 21. Basal PWT and TFL also significantly decreased during the SNP treatment period. The lower nociceptive thresholds recovered in 6 days following the final SNP injection in SNP group, but not in SPS + SNP group. Elevated nociceptin/OFQ (N/OFQ) levels observed in cerebrospinal fluid of SPS rats were even higher in SPS + SNP group. Glial fibrillary acidic protein (GFAP) and N/OFQ peptide (NOP) receptor mRNA expression increased in dorsal root ganglia (DRG) 21 days after SPS exposure; mRNA increases in the SPS/SNP group was more pronounced than SPS or SNP alone. GFAP protein expression was upregulated in trigeminal ganglia by SPS. Our results indicate that traumatic stress exaggerated chronic SNP-induced nociceptive hypersensitivity, and that N/OFQ and activated satellite glia cells may play an important role in the interaction between both conditions.

Protective effects of fusidic acid against sodium nitroprusside-induced apoptosis in C6 glial cells.

Fusidic acid, a steroidal antibiotic, possesses antimicrobial, antioxidant, and anti-inflammatory properties, but the effect of fusidic acid against neurodegenerative disease-related cell death has not been studied. Here, we investigated the protective effects of fusidic acid on sodium nitroprusside (SNP)-induced toxicity in C6 glial cells. Fusidic acid (5-20 µM) prevented SNP (100 µM)-induced cell death dose dependently, and effectively attenuated SNP-induced generation of nitric oxide (NO), total reactive oxygen species (ROS), and peroxynitrite (ONOO). Fusidic acid (20 µM) pretreatment significantly suppressed SNP (100 µM)-induced apoptotic events, such as nuclear condensation and caspase-3 activation. In addition, fusidic acid effectively attenuated SNP-induced endoplasmic reticulum (ER) stress markers, such as GRP78, IRE1, ATF6, PERK, XBP1s, eIF2α, CHOP, and caspase-12. A specific adenosine monophosphate-activated protein kinase (AMPK) inhibitor, compound C (10 µM), reversed the preventive effects of fusidic acid against SNP-induced cytotoxicity, CHOP elevation, and caspase-3 activation. These results suggest that fusidic acid can protect C6 glial cells against cytotoxicity, through the regulation of AMPK pathway and apoptotic events.

Activation of anti-oxidant of curcumin pyrazole derivatives through preservation of mitochondria function and Nrf2 signaling pathway.

Oxidative stress is an important cause of neurodegenerative diseases. Antioxidant is an potential important method to treat such diseases. The aim of this study is to discover new and effective antioxidants and their mechanism. The neuroprotective effect of six curcumin pyrozole compounds were first evaluated on sodium nitroprusside (SNP) - induced PC12 cell injury by testing cell viability and LDH release. The results showed that four compounds (C1-C4) have more significant protective effects compared to curcumin and edaravone. Furthermore, compounds C1-C4 can attenuate the intracellular ROS, and compound C3 is the most effective one which can preservate the mitochondria function by inhibiting the mitochondrial membrane potential loss and enhance nuclear translocation of Nrf2 in PC12 cell. These results indicated that C3 may be a potential candidate drug for treating neurodegenerative diseases.

NXY-059, a Failed Stroke Neuroprotectant, Offers No Protection to Stem Cell-Derived Human Neurons.

BACKGROUND: Developing new medicines is a complex process where understanding the reasons for both failure and success takes us forward. One gap in our understanding of most candidate stroke drugs before clinical trial is whether they have a protective effect on human tissues. NXY-059 is a spin-trap reagent hypothesized to have activity against the damaging oxidative biology which accompanies ischemic stroke. Re-examination of the preclinical in vivo dataset for this agent in the wake of the failed SAINT-II RCT highlighted the presence of a range of biases leading to overestimation of the magnitude of NXY-059's effects in laboratory animals. Therefore, NXY-059 seemed an ideal candidate to evaluate in human neural tissues to determine whether human tissue testing might improve screening efficiency. MATERIALS AND METHODS: The aim of this randomized and blinded study was to assess the effects of NXY-059 on human stem cell-derived neurons in the presence of ischemia-like injury induced by oxygen glucose deprivation or oxidative stress induced by hydrogen peroxide or sodium nitroprusside. RESULTS: In MTT assays of cell survival, lactate dehydrogenase assays of total cell death and terminal deoxynucleotidyl transferase dUTP nick end labeling staining of apoptotic-like cell death, NXY-059 at concentrations ranging from 1 µm to 1 mm was completely without activity. Conversely an antioxidant cocktail comprising 100 µm each of ascorbate, reduced glutathione, and dithiothreitol used as a positive control provided marked neuronal protection in these assays. CONCLUSION: These findings support our hypothesis that stroke drug screening in human neural tissues will be of value and provides an explanation for the failure of NXY-059 as a human stroke drug.

Anti-apoptotic effect of interleukin-22 on fibroblast-like synoviocytes in patients with rheumatoid arthritis is mediated via the signal transducer and activator of transcription 3 signaling pathway.

AIM: Inadequate apoptosis of fibroblast-like synoviocytes (FLS) plays a crucial role in the immunopathogenesis of rheumatoid arthritis (RA). Interleukin-22 (IL-22) is a novel member of the cytokine network that has been found to be involved in the immunological process underlying RA. In this study, we investigated the effect of IL-22 on the survival of RA-FLS from RA patients and examined the possible mechanism to determine new therapeutic strategies for RA. METHODS: FLS obtained from patients with RA were cultured in vitro and treated with sodium nitroprussiate (SNP) to induce apoptosis in the presence or absence of IL-22. RA-FLS viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RA-FLS apoptosis was analyzed by annexin V/propidium iodide staining (AV/PI). The levels of IL-22R1, pSTAT3-Y705, pSTAT3-S727, total STAT3, Bcl-xL and Bcl-2 were detected by Western blot analysis. RESULTS: IL-22R1 was expressed on RA-FLS. IL-22 pretreatment at concentrations ranging from 10 to 100 ng/mL increased RA-FLS viability and prevented SNP-induced apoptosis. Treatment with the STAT3 inhibitors, HO3867 or STA21, reversed the protective effect of IL-22 on SNP-induced apoptosis of RA-FLS. IL-22-induced phosphorylation of STAT3 (pSTAT3-Y705 and pSTAT3-S727) was increased in RA-FLS. Also IL-22 increased Bcl-2 expression in SNP-treated RA-FLS, and the effect was reversed by treatment with HO3867 or STA21. CONCLUSION: IL-22 protects against SNP-induced apoptosis in RA-FLS by activating the STAT3 pathway and the downstream target gene, Bcl-2. Therefore, therapeutic strategies that target the IL-22/STAT3 pathway are implicated as candidates for RA treatment.

Dural stimulation in rats causes brain-derived neurotrophic factor-dependent priming to subthreshold stimuli including a migraine trigger.

Migraine is one of the most common and most disabling disorders. Between attacks, migraine patients are otherwise normal but are sensitized to nonnoxious events known as triggers. The purpose of these studies was to investigate whether a headache-like event causes sensitization, or priming, to subsequent subthreshold events. Interleukin-6 (IL-6) was applied to the rat cranial dura mater which produced cutaneous facial and hind paw allodynia that lasted 24 hours. At 72 hours, IL-6-treated rats developed allodynia in response to dural stimulation with either a pH 6.8 or pH 7.0 solution and to a systemic nitric oxide (NO) donor, a well-known migraine trigger. Vehicle-treated rats did not respond to either pH stimulus or to the NO donor, demonstrating that IL-6 exposure primes rats to subthreshold stimuli. Inhibitors of brain-derived neurotrophic factor (BDNF) signaling given either systemically or intracisternally 24 hours after IL-6 eliminated responses to dural pH stimulation at 72 hours. Additionally, intracisternal administration of BDNF without previous dural stimulation produced allodynia and once resolved, animals were primed to dural pH 6.8/pH 7.0 and a systemic NO donor. Finally, hind paw IL-6 produced paw allodynia but not priming to paw injection of pH 7.0 at 72 hours demonstrating differences in priming depending on location. These data indicate that afferent input from the meninges produces BDNF-dependent priming of the dural nociceptive system. This primed state mimics the interictal period of migraine where attacks can be triggered by normally nonnoxious events and suggests that BDNF-dependent plasticity may contribute to migraine.

Inhibitory effects of SRT1720 on the apoptosis of rabbit chondrocytes by activating SIRT1 via p53/bax and NF-κB/PGC-1α pathways.

SRT1720, a new discovered drug, was reported to activate silent information regulator 1 (SIRT1) and inhibit the chondrocyte apoptosis. However, the underlying mechanism remains elusive. In the present study, the chondrocytes were extracted from the cartilage tissues of New Zealand white rabbits, cultured in the presence of sodium nitroprusside (SNP) (2.5 mmol/L) and divided into five groups: 1, 5, 10, and 20 µmol/L SRT1720 groups and blank control group (0 µmol/L SRT1720). MTT assay was used to detect the chondrocyte viability and proliferation, and DAPI staining and flow cytometry to measure the chondrocyte apoptosis. The expression levels of SIRT1, p53, NF-κB/p65, Bax, and peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) were detected by Western blotting and the expression levels of SIRT1, type II collagen, and aggrecan mRNA by RT-PCR. The results showed that in the SRT1720-treated groups, the nuclei of chondrocytes were morphologically intact and had uniform chromatin. In the blank control group, nuclear rupture into debris was observed in chondrocytes. With the SRT1720 concentration increasing, the chondrocyte viability increased, the apoptosis rate decreased, the protein expression levels of SIRT1 and PGC-1α and the mRNA expression levels of type II collagen and aggrecan increased ({ptP}<0.05), and the expression levels of p53, NF-κB and bax decreased (P<0.05). It was suggested that SRT1720 inhibits chondrocyte apoptosis by activating the expression of SIRT1 via p53/bax and NF-κB/PGC-1α pathways.

Protective Effect of Dimethyl Fumarate on an Oxidative Stress Model Induced by Sodium Nitroprusside in Mice.

Recent reports have shown that dimethyl fumarate (DMF) prevents brain damage induced by intracerebral hemorrhage and this beneficial effect is mediated by the nuclear erythroid 2 p45-related factor-2-antioxidant response element (Nrf2-ARE) pathway. However, the downstream mechanism underlying the activation of the Nrf2-ARE pathway is unclear. Here, we investigated the protective effect of DMF using an in vivo model of oxidative stress induced by sodium nitroprusside (SNP) and rat primary striatal cultures. Oral administration of DMF prevented SNP-induced motor dysfunction. Pre-administration of DMF (60-200 mg/kg) for 24 h dose-dependently protected against brain damage induced by the striatal injection of SNP. Next, we investigated the protective effect and mechanism of DMF against oxidative stress using rat primary striatal cell cultures. Treatment of striatal cells with DMF (10 µM) markedly prevented hydrogen peroxide-induced cytotoxicity. The protective effect of DMF against oxidative stress in vitro was inhibited by zinc protoporphyrin IX, an inhibitor of heme oxygenase-1, but not by buthionine sulfoximine, an inhibitor of glutathione synthesis. These results suggest that the activation of heme oxygenase-1 plays an important role in the protective effect of DMF.

Artemisinin conferred ERK mediated neuroprotection to PC12 cells and cortical neurons exposed to sodium nitroprusside-induced oxidative insult.

The production of nitric oxide (NO) is one of the primary mediators of ischemic damage, glutamate neurotoxicity and neurodegeneration and therefore inhibition of NO-induced neurotoxicity may be considered a therapeutic target for reducing neuronal cell death (neuroprotection). In this study, artemisinin, a well-known anti-malaria drug was found to suppress sodium nitroprusside (SNP, a nitric oxide donor)-induced cell death in the PC12 cells and brain primary cortical neuronal cultures. Pretreatment of PC12 cells with artemisinin significantly suppressed SNP-induced cell death by decreasing the extent of oxidation, preventing the decline of mitochondrial membrane potential, restoring abnormal changes in nuclear morphology and reducing lactate dehydrogenase release and inhibiting caspase 3/7 activities. Western blotting analysis revealed that artemisinin was able to activate extracellular regulated protein kinases (ERK) pathway. Furthermore, the ERK inhibitor PD98059 blocked the neuroprotective effect of artemisinin whereas the PI3K inhibitor LY294002 had no effect. Cumulatively these findings support the notion that artemisinin confers neuroprotection from SNP-induce neuronal cell death insult, a phenomenon coincidentally related to activation of ERK phosphorylation. This SNP-induced oxidative insult in PC12 cell culture model may be useful to investigate molecular mechanisms of NO-induced neurotoxicity and drug-induced neuroprotection, and to generate novel therapeutic concepts for ischemic disease treatment.

Alpha-ketoglutarate attenuates toxic effects of sodium nitroprusside and hydrogen peroxide in Drosophila melanogaster.

The protective effects of dietary alpha-ketoglutarate (AKG) are described that aid fruit flies, Drosophila melanogaster, to resist sodium nitroprusside (SNP) and hydrogen peroxide toxicity. Food supplementation with 10mM AKG alleviated toxic effects of 1mM SNP added to food and improved fly development. Dietary AKG also prevented the increase in levels of oxidative stress markers seen in SNP-reared adult flies. In vitro AKG did not affect the rate of SNP decomposition and did not bind iron and nitrite ions released in this process. Alpha-ketoglutarate also displayed high H2O2-scavenging activity in vitro and efficiently protected adult flies against this compound in combined treatments. Based on the observed antioxidant activity of AKG, it may be suggested that the antioxidant mode of AKG action (apart from its cyanide-binding capability) may be used to prevent the toxic effects of SNP and improve general physiological state of D. melanogaster and other animals and humans.

Rutin, A Natural Flavonoid Protects PC12 Cells Against Sodium Nitroprusside-Induced Neurotoxicity Through Activating PI3K/Akt/mTOR and ERK1/2 Pathway.

Free radicals induced neural damage is implicated in CNS diseases and rutin isolated form Lonicera japonica are reported to have neuroprotective activity. Previously, we confirmed that rutin exerted neuroprotective effect against sodium nitroprusside (SNP)-induced cell death in PC12 cells. However, the neuroprotective mechanism of rutin is still not fully uncovered. Here, we found that rutin significantly decreased SNP-induced reactive oxygen species in PC12 cells. Rutin reversed the declined GSH/GSSG ratio and mitochondrial membrane potential induced by SNP. Moreover, rutin activated both the protein Akt/mTOR and the extracellular signal-regulated kinase (ERK1/2) signaling pathways and the neuroprotective effects of rutin were blocked by either the specific PI3K inhibitor LY294002 or the MAPK pathway inhibitor PD98059. In summary, these results demonstrated that the neuroprotective effects of rutin might be through activating both the PI3K/Akt/mTOR and ERK1/2 signaling pathways. Our findings support that rutin may have therapeutic potential for the treatment of CNS diseases related to NO neurotoxicity.

Xanthan gum protects rabbit articular chondrocytes against sodium nitroprusside-induced apoptosis in vitro.

We have previously reported that intra-articular injection of xanthan gum (XG) could significantly ameliorate the degree of joint cartilage degradation and pain in experimental osteoarthritis (OA) model in vivo. In this present study, we evaluated the protective effect of XG against Sodium nitroprusside (SNP)-induced rabbit articular chondrocytes apoptosis in vitro. Rabbit articular chondrocytes were incubated with various concentrations of XG for 24h prior to 0.5mmol/L SNP co-treatment for 24h. The proliferation of chondrocytes was analyzed using MTT assay. The chondrocytes early apoptosis rates were evaluated using Annexin V-FITC/PI flow cytometry. The morphology of apoptosis chondrocytes were observed by scanning electron microscopy (SEM). The loss/disruption of mitochondrial membrane potential was detected using rhodamin 123 by confocal microscope. The concentration of prostaglandin E2 (PGE2) in cell culture supernatants was evaluated using ELISA assay. The results showed that XG could significantly reverse SNP-reduced cell proliferation and inhibited cell early apoptosis rate in a dose-dependent manner. XG alleviated loss/disruption of mitochondrial membrane potential and decreased the PGE2 level of chondrocytes cell culture supernatants in SNP-induced chondrocytes. These results of the present research strongly suggest that XG can protect rabbit articular chondrocytes against SNP-induced apoptosis in vitro.

Inhibition of neuronal p38α, but not p38ß MAPK, provides neuroprotection against three different neurotoxic insults.

The p38 mitogen-activated protein kinase (MAPK) pathway plays a key role in pathological glial activation and neuroinflammatory responses. Our previous studies demonstrated that microglial p38α and not the p38ß isoform is an important contributor to stressor-induced proinflammatory cytokine upregulation and glia-dependent neurotoxicity. However, the contribution of neuronal p38α and p38ß isoforms in responses to neurotoxic agents is less well understood. In the current study, we used cortical neurons from wild-type or p38ß knockout mice, and wild-type neurons treated with two highly selective inhibitors of p38α MAPK. Neurons were treated with one of three neurotoxic insults (L-glutamate, sodium nitroprusside, and oxygen-glucose deprivation), and neurotoxicity was assessed. All three stimuli led to neuronal death and neurite degeneration, and the degree of neurotoxicity induced in wild-type and p38ß knockout neurons was not significantly different. In contrast, selective inhibition of neuronal p38α was neuroprotective. Our results show that neuronal p38ß is not required for neurotoxicity induced by multiple toxic insults, but that p38α in the neuron contributes quantitatively to the neuronal dysfunction responses. These data are consistent with our previous findings of the critical importance of microglia p38α compared to p38ß, and continue to support selective targeting of the p38α isoform as a potential therapeutic strategy.

Protective effects of resveratrol oligomers from Vitis amurensis against sodium nitroprusside-induced neurotoxicity in human neuroblastoma SH-SY5Y cells.

Nitric oxide (NO) induces apoptosis in neuronal cells, and has been implicating in a variety of neuronal pathological process. Thus, there is much interest in identifying natural substances which have protective effects against damage induced by nitrosative stress. The roots of Vitis amurensis have been used as traditional medicine and contain structurally diverse resveratrol oligomers with various biological activities. However, there have been few studies on the protective effect of resveratrol oligomers against neurotoxic reactive nitrogen species. In this study, we evaluated the protective effects of two resveratrol oligomers from V. amurensis, vitisin A and heyneanol A, against NO-induced toxicity. Additionally, their antioxidant activities were determined by measuring NO and hydroxyl radical scavenging ability. Both vitisin A and heyneanol A reduced cell death and DNA fragmentation induced by sodium nitroprusside in SH-SY5Y cells. The present study indicates that radical scavenging activities of vitisin A and heyneanol A contribute to protecting neuronal cells against nitrosative stress.

IGF-1 signaling via the PI3K/Akt pathway confers neuroprotection in human retinal pigment epithelial cells exposed to sodium nitroprusside insult.

The pathological increase in the levels of the second messenger nitric oxide (NO) in the vitreous cavity and retina leads to injury and cell death of the retinal pigment epithelium (RPE) cells and eventually may contribute to the occurrence and development of diabetic retinopathy. In this study, we developed a cellular model of retinopathy using D407 cells (a human RPE cell line) exposed to sodium nitroprusside (SNP) and investigated the protective effect of the insulin-like growth factor-1 (IGF-1) towards this insult. Cell death and apoptosis were examined by the methyl thiazolyl tetrazolium assay and Hoechst staining, respectively. Specific inhibitors were used and phosphorylation of relevant signaling proteins was determined by Western blotting. SNP, in a concentration-dependent fashion, increased the production of reactive oxygen species (ROS) and lipid peroxidation process causing cell death by apoptosis of D407 cells. IGF-1, in a time- and dose-dependent manner, conferred protection towards SNP-mediated insult. Both phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) and mitogen-activated protein kinase (MAPK) were activated by IGF-1 in relation to the protective effect. Blockade of the PI3K/Akt pathway abolished the protective effect of IGF-1 whereas inhibition of the MAPK pathway was ineffective. SNP decreased the phosphorylation of Akt in the cells while IGF-1 reversed this inhibitory effect. These results indicate that the protective effect of IGF-1 on D407 exposed to SNP insult is mediated by the PI3K/Akt pathway. This proposal may be exploited in the clinic to improve the viability of insulted retinal cells for maintaining physiological vision.

[Protective effect of rutin against oxidative injury in neuronal cells].

OBJECTIVE: To observe the protective effect of rutin (RUT) on neuronal cells against sodium nitroprusside (SNP) induced neurotoxicity. METHODS: PC12 cells were treated with different concentration of SNP for 24 h and MTT assay was applied to analyze the survival rate; PC12 cells were pretreated with rutin for 1 h, and then incubated for 24 h with SNP. MTT assay, morphological observation, as well as immunofluorescence were performed to evaluate both the SNP neurotoxicity and the protective effects of RUT, Western blot was used to analyzed the level of phosphorylated extra cellular regulated protein kinases (ERK1/2) after treatment with RUT, the results were also testified in primary cultured neurons. RESULTS: Results from MTT assay showed that SNP caused cell death in a concentration-dependent manner in PC12 cells. The effect of SNP was observed at 200 - 1 000 micromol/L and was significant at 800 micromol/L. 25 micromol/L rutin partly blocked the neurotoxicity of SNP by preventing PC12 cells from apoptosis. Hoechst and PI staining indicated that SNP treatment decreased the number of viable cells and induced shrinkage and aggregation of the nucleus, whereas RUT pretreatment attenuated the toxic effects of SNP, after treatment with RUT in PC12 cells, the phosphorylation of ERK1/2 was increased and peaked at 20 min. Most importantly, the protective effect of RUT on PC12 cells was confirmed on cultured neurons. CONCLUSION: RUT possesses protective effect against neuronal apoptosis induced by SNP and this effect may be partially related with ERK1/2 signaling.

α-Lipoic acid protected cardiomyoblasts from the injury induced by sodium nitroprusside through ROS-mediated Akt/Gsk-3ß activation.

It has been long noted that cardiac cell apoptosis provoked by excessive production of nitric oxide (NO) plays important roles in the pathogenesis of variant cardiac diseases. Attenuation of NO-induced injury would be an alternative therapeutic approach for the development of cardiac disorders. This study investigated the effects of α-lipoic acid (LA) on the injury induced by sodium nitroprusside (SNP), a widely used NO donor, in rat cardiomyoblast H9c2 cells. SNP challenge significantly decreased cell viability and increased apoptosis, as evidenced by morphological abnormalities, nuclear condensation and decline of mitochondrial potential (ΔΨm). These changes induced by SNP were significantly attenuated by LA pretreatment. Furthermore, LA pretreatment prevented the SNP-triggered suppression of Akt and Gsk-3ß activation. Blockade of Akt activation with triciribin (API) completely abolished the cytoprotection of LA against SNP challenge. In addition, LA moderately increased intracellular ROS production. Interestingly, inhibition of ROS with N-acetylcysteine abrogated Akt/Gsk-3ß activation and the LA-induced cytoprotection following SNP stimulation. Taken together, the results indicate that LA protected the SNP-induced injury in cardiac H9c2 cells through, at least in part, the activation of Akt/Gsk-3ß signaling in a ROS-dependent mechanism.

Dosing-time dependent oxidative effects of sodium nitroprusside in brain, kidney, and liver of mice.

UNLABELLED: The purpose of this study was to investigate if the oxidative effects of sodium nitroprusside (SNP) are dosing-time dependent. Therefore, the variation of malondialdehyde (MDA) status was assessed after a single i.p. administration of SNP (2.5mgkg(-1) b.w.) or vehicle (9‰ NaCl) to different and comparable groups of mice (n=48) at two different circadian times (1 and 13h after light onset [HALO]). Brain, kidney, and liver tissues were excised over 36h, and their MDA contents were estimated at 0, 1, 3, 6, 9, 12, 24, and 36h after SNP administration. RESULTS: indicated mean MDA level was not significantly changed in each investigated tissue compared with the control. In contrast, the mean MDA value varied among organs and was comparable in brain and liver but lower than in kidney. The data show SNP significantly (P<0.05) increases MDA status in both tissues and exerts time-dependent oxidative effects with the greatest toxicity coinciding with the beginning of the diurnal rest span (local time: 08:00h, i.e., at 1 HALO). The obtained results reveal SNP-induced oxidative damage (evidenced by MDA accumulation) varies according to both the dosing-time and the target organ.