Inhibition of ROS-activated p38MAPK pathway is involved in the protective effect of H2S against chemical hypoxia-induced inflammation in PC12 cells

Antioxidant Activity and Chemical Composition of Geranium Oil and Its Synergistic Potential against Pneumococci with Various Antibiotic Combinations

The essential oil of Pelargonium graveolens L. is valuable for its therapeutic benefits, so this study aimed to determine the synergistic effect of the combination of the essential oil of this plant with antibiotics instead of the extracts prepared with various solvents. In addition, the second goal of this study was to determine whether the essential oil combined with various antibiotics increased the overall killing activity in mouse macrophage cells with the aim of introducing an immunotherapeutic approach to the infection treatments used today. Herein, the volatile profile of Geranium oil (G.O) was analyzed using GC/MS. The current study sought to assess the synergistic characteristics of several antibiotic combinations using G.O against pneumococci, as well as the oil's antioxidant and antimicrobial activities. The major components of the oil were citronellol, geraniol, and isomenthone. In the combinations of G.O and antibiotics, the synergism of the Streptococcus pneumoniae to antibiotics advanced. When the time-kill data were evaluated, G.O + antibiotic combinations quickly diminished the viable cell count of S. pneumoniae from the 6th h. In this study, the combined use of existing antibiotics used in infection treatments with G.O could improve antibiotic effectiveness and thus prevent bacteria from developing antibiotic resistance.

Impact Assessment of Lead-Tolerant Rhizobacteria to Improve Soil Health Using Indian Mustard (Brassica juncea) as an Indicator Plant

Due to ongoing human activities, heavy metals are heavily accumulated in the soil. This leads to an increase in the discharge and the quick spread of heavy metal pollution in human settlements and natural habitats, having a disastrous effect on agricultural products. The current experiment was planned to evaluate the effect of lead-tolerant-plant-growth-promoting rhizobacteria (LTPGPR) on growth, yield, antioxidant activities, physiology, and lead uptake in the root, shoot, and seed of Indian mustard (Brassica juncea) in lead-amended soil. Three pre-isolated well-characterized lead-tolerant rhizobacterial strains-S10, S5, and S2-were used to inoculate seeds of Indian mustard grown at three different levels of lead (300 mg kg-1, 600 mg kg-1, 900 mg kg-1) contaminated soil. The experiment was designed following a completely randomized design (CRD) under factorial arrangements. Lead nitrate was used as a source of lead contamination. At harvesting, data regarding growth, physiology, yield per plant, antioxidant activities, malondialdehyde and proline content, and lead uptake in the root, shoot, and seed of Indian mustard were recorded. Results demonstrated that lead contamination at all levels significantly reduced the plant growth, yield, and physiological processes. Plants inoculated with lead-tolerant rhizobacteria showed a significant improvement in plant growth, yield, antioxidant activities, and physiological attributes and cause a valuable reduction in the malondialdehyde contents of Indian mustard in lead-contaminated soil. Moreover, plants inoculated with lead-tolerant rhizobacteria also showed an increment in lead uptake in the vegetative parts and a significant reduction of lead contents in the seed of Indian mustard.

Sulfanegen stimulates 3-mercaptopyruvate sulfurtransferase activity and ameliorates Alzheimer's disease pathology and oxidative stress in vivo

Increased oxidative stress and inflammation are implicated in the pathogenesis of Alzheimer's disease. Treatment with hydrogen sulfide (H2S) and H2S donors such as sodium hydrosulfide (NaSH) can reduce oxidative stress in preclinical studies, however clinical benefits of such treatments are rather ambiguous. This is partly due to poor stability and bioavailability of the H2S donors, requiring impractically large doses that are associated with dose-limiting toxicity. Herein, we identified a bioavailable 3-mercaptopyruvate prodrug, sulfanegen, which is able to pose as a sacrificial redox substrate for 3-mercaptopyruvate sulfurtransferase (3MST), one of the H2S biosynthetic enzymes in the brain. Sulfanegen is able to mitigate toxicity emanating from oxidative insults and the Aβ1-42 peptide by releasing H2S through the 3MST pathway. When administered to symptomatic transgenic mouse model of AD (APP/PS1; 7 and 12 months) and mice that were intracerebroventricularly administered with the Aβ1-42 peptide, sulfanegen was able to reverse oxidative and neuroinflammatory consequences of AD pathology by restoring 3MST function. Quantitative neuropathological analyses confirmed significant disease modifying effect of the compound on amyloid plaque burden and brain inflammatory markers. More importantly, sulfanegen treatment attenuated progressive neurodegeneration in these mice, as evident from the restoration of TH+ neurons in the locus coeruleus. This study demonstrates a previously unknown concept that supplementation of 3MST function in the brain may be a viable approach for the management of AD. Finally, brought into the spotlight is the potential of sulfanegen as a promising AD therapeutic for future drug development efforts.

Redox Signaling and Advanced Glycation Endproducts (AGEs) in Diet-Related Diseases

Diets are currently characterized by elevated sugar intake, mainly due to the increased consumption of processed sweetened foods and drinks during the last 40 years. Diet is the main source of advanced glycation endproducts (AGEs). These are toxic compounds formed during the Maillard reaction, which takes place both in vivo, in tissues and fluids under physiological conditions, favored by sugar intake, and ex vivo during food preparation such as baking, cooking, frying or storage. Protein glycation occurs slowly and continuously through life, driving AGE accumulation in tissues during aging. For this reason, AGEs have been proposed as a risk factor in the pathogenesis of diet-related diseases such as diabetes, insulin resistance, cardiovascular diseases, kidney injury, and age-related and neurodegenerative diseases. AGEs are associated with an increase in oxidative stress since they mediate the production of reactive oxygen species (ROS), increasing the intracellular levels of hydrogen peroxide (H₂O₂), superoxide (O₂⁻), and nitric oxide (NO). The interaction of AGEs with the receptor for AGEs (RAGE) enhances oxidative stress through ROS production by NADPH oxidases inside the mitochondria. This affects mitochondrial function and ultimately influences cell metabolism under various pathological conditions. This short review will summarize all evidence that relates AGEs and ROS production, their relationship with diet-related diseases, as well as the latest research about the use of natural compounds with antioxidant properties to prevent the harmful effects of AGEs on health.

Biomedical Applications for Gold Nanoclusters: Recent Developments and Future Perspectives

Gold nanoclusters (AuNCs) have been extensively applied as a fluorescent probe for biomedical applications in imaging, detection, and therapy due to their unique chemical and physical properties. Fluorescent probes of AuNCs have exhibited high compatibility, superior photostablility, and excellent water solubility which resulted in remarkable biomedical applications for long-term imaging, high-sensitivity detection, and target-specific treatment. Recently, great efforts have been made in the developments of AuNCs as the fluorescent probes for various biomedical applications. In this review, we have collected fluorescent AuNCs prepared by different ligands, including small molecules, polymers, and biomacromolecules, and highlighted current achievements of AuNCs in biomedical applications for imaging, detection, and therapy. According to these advances, we further provided conclusions of present challenges and future perspectives of AuNCs for fundamental investigations and practical biomedical applications.

4'-Methoxyresveratrol Alleviated AGE-Induced Inflammation via RAGE-Mediated NF-κB and NLRP3 Inflammasome Pathway

Advanced glycation end products (AGEs) could interact with the receptor for AGE (RAGE) as a sterile danger signal to induce inflammation. 4′-methoxyresveratrol (4′MR), a polyphenol derived from Dipterocarpaceae, has not been studied for its anti-inflammation effects. In the present study, we sought to explore the protective role of 4′MR in AGEs-induced inflammatory model using RAW264.7 macrophages. 4′MR significantly inhibited gene expression of pro-inflammatory cytokines and chemokines, such as interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α) and monocyte chemoattractant protein-1 (MCP-1), as well as two typical pro-inflammatory enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2). Besides, 4′MR significantly decreased oxidative stress, demonstrated by levels of ROS production, protein carbonyl and advanced oxidation protein product via down-regulation of NADPH oxidase. Further analysis showed that 4′MR attenuated the RAGE overexpression induced by MGO-BSA. It also blocked the downstream signal of AGE-RAGE, particularly, MAPKs including p38 and JNK, and subsequently reduced NF-κB activation. Additionally, 4′MR significantly abated the activation of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome including NLRP3 and cleaved caspase-1 and reduced the secretion of mature IL-1β. Taken together, our results suggest that the anti-inflammatory effect of 4′MR is mainly through suppressing RAGE-mediated MAPK/NF-κB signaling pathway and NLRP3 inflammasome activation. 4′MR could be a novel therapeutic agent for inflammation-related diseases.

Salvianolic acid B suppresses cell proliferation and induces apoptosis in osteosarcoma through p38-mediated reactive oxygen species generation

The present study aimed to investigate the potential anticancer effect and mechanisms of salvianolic acid B on osteosarcoma. Salvianolic acid B suppressed osteosarcoma cell proliferation and induced apoptosis in the osteosarcoma MG63 cell line, and activated the expressions of cleaved caspase-3, phosphorylated-tumor protein (p)38 mitogen-activated protein kinase (p-p38 MAPK) and phosphorylated-p53 (p-p53) proteins in the MG63 cells. Additionally, Salvianolic acid B also increased the level of reactive oxygen species (ROS) generation in the MG63 cells. The silencing of p38 expression inhibited the anticancer effect of salvianolic acid B on the levels of cell proliferation, p-p53 protein expression and ROS generation level in the MG63 cells. All these data supported the hypothesis that the anticancer effect of salvianolic acid B includes the suppression of cell proliferation and induces apoptosis in MG63 cells, and that p38 is important in the anticancer effect of salvianolic acid B on osteosarcoma cells due to the direct regulation of ROS generation. These data suggest that salvianolic acid B is important in the proliferation of osteosarcoma cells due to the direct regulation of p38-mediated ROS signaling.

Hydrogen Sulfide Exerts Anti-oxidative and Anti-inflammatory Effects in Acute Lung Injury

Acute lung injury (ALI) caused by septic stimuli is still a major problem in critical care patients. We have shown previously that hydrogen sulfide (H2S) mediates anti-inflammatory and lung protective effects. In the present study, we aimed to investigate the underlying mechanisms. C57BL/6N mice were instilled with lipopolysaccharide (LPS) intranasally in the absence or presence of inhaled H2S for 6 h. LPS instillation led to alveolar wall thickening, an elevated ALI score, increased neutrophil transmigration, and elevated interleukin-1β cytokine release into the bronchoalveolar lavage fluid. In contrast, H2S inhalation prevented lung injury and inflammation despite LPS treatment. Moreover, H2S inhalation significantly inhibited protein expression of cystathionine-β-synthetase, heat shock protein 70, phosphorylated p38 MAP kinase, NADPH oxidase 2, and the formation of reactive oxygen species (ROS) in LPS-challenged animals. In conclusion, H2S prevents LPS-induced ALI by inhibition of pro-inflammatory and oxidative responses via the concerted attenuation of stress protein, MAP kinase, and ROS signaling pathways.

Luminescent gold nanocluster-based sensing platform for accurate H2S detection in vitro and in vivo with improved anti-interference

Gold nanoclusters (Au NCs) are promising luminescent nanomaterials due to their outstanding optical properties. However, their relatively low quantum yields and environment-dependent photoluminescence properties have limited their biological applications. To address these problems, we developed a novel strategy to prepare chitosan oligosaccharide lactate (Chi)-functionalized Au NCs (Au NCs@Chi), which exhibited emission with enhanced quantum yield and elongated emission lifetime as compared to the Au NCs, as well as exhibited environment-independent photoluminescence properties. In addition, utilizing the free amino groups of Chi onto Au NCs@Chi, we designed a FRET-based sensing platform for the detection of hydrogen sulfide (H₂S). The Au NCs and the specific H₂S-sensitive merocyanine compound were respectively employed as an energy donor and acceptor in the platform. The addition of H₂S induced changes in the emission profile and luminescence lifetime of the platform with high sensitivity and selectivity. Utilization of the platform was demonstrated to detect exogenous and endogenous H₂S in vitro and in vivo through wavelength-ratiometric and time-resolved luminescence imaging (TLI). Compared to previously reported luminescent molecules, the platform was less affected by experimental conditions and showed minimized autofluorescence interference and improved accuracy of detection.

Fish Scale Collagen Peptides Protect against CoCl2/TNF-α-Induced Cytotoxicity and Inflammation via Inhibition of ROS, MAPK, and NF-κB Pathways in HaCaT Cells

Skin diseases associated with inflammation or oxidative stress represent the most common problem in dermatology. The present study demonstrates that fish scale collagen peptides (FSCP) protect against CoCl₂-induced cytotoxicity and TNF-α-induced inflammatory responses in human HaCaT keratinocyte cells. Our study is the first to report that FSCP increase cell viability and ameliorate oxidative injury in HaCaT cells through mechanisms mediated by the downregulation of key proinflammatory cytokines, namely, TNF-α, IL-1β, IL-8, and iNOS. FSCP also prevent cell apoptosis by repressing Bax expression, caspase-3 activity, and cytochrome c release and by upregulating Bcl-2 protein levels in CoCl₂- or TNF-α-stimulated HaCaT cells. In addition, the inhibitory effects of FSCP on cytotoxicity and the induction of proinflammatory cytokine expression were found to be associated with suppression of the ROS, MAPK (p38/MAPK, ERK, and JNK), and NF-κB signaling pathways. Taken together, our data suggest that FSCP are useful as immunomodulatory agents in inflammatory or immune-mediated skin diseases. Furthermore, our results provide new insights into the potential therapeutic use of FSCP in the prevention and treatment of various oxidative- or inflammatory stress-related inflammation and injuries.

Pre- and posttreatment with hydrogen sulfide prevents ventilator-induced lung injury by limiting inflammation and oxidation

Although essential in critical care medicine, mechanical ventilation often results in ventilator-induced lung injury. Low concentrations of hydrogen sulfide have been proven to have anti-inflammatory and anti-oxidative effects in the lung. The aim of this study was to analyze the kinetic effects of pre- and posttreatment with hydrogen sulfide in order to prevent lung injury as well as inflammatory and oxidative stress upon mechanical ventilation. Mice were either non-ventilated or mechanically ventilated with a tidal volume of 12 ml/kg for 6 h. Pretreated mice inhaled hydrogen sulfide in low dose for 1, 3, or 5 h prior to mechanical ventilation. Posttreated mice were ventilated with air followed by ventilation with hydrogen sulfide in various combinations. In addition, mice were ventilated with air for 10 h, or with air for 5 h and subsequently with hydrogen sulfide for 5 h. Histology, interleukin-1β, neutrophil counts, and reactive oxygen species formation were examined in the lungs. Both pre-and posttreatment with hydrogen sulfide time-dependently reduced or even prevented edema formation, gross histological damage, neutrophil influx and reactive oxygen species production in the lung. These results were also observed in posttreatment, when the experimental time was extended and hydrogen sulfide administration started as late as after 5 h air ventilation. In conclusion, hydrogen sulfide exerts lung protection even when its application is limited to a short or delayed period. The observed lung protection is mediated by inhibition of inflammatory and oxidative signaling.

The protective effects of resveratrol, H2S and thermotherapy on the cell apoptosis induced by CdTe quantum dots

Quantum dots (QDs) could be used in the field of biology and medicine as excellent nano-scale fluorescent probes due to their unique optical properties, but the adverse effects of QDs are always the obstruction for its usage in living organisms. In this study, we observed that CdTe QDs exposure decreased the cell viability while increased the apoptosis rates in the L929 cells. Apart from QD-induced oxidative stress indicated by excessive ROS generation, three signal transductions, including Akt, p38 and JNK, played important roles on the regulation of cell apoptosis by CdTe QDs exposure as well. In order to reduce the toxicity of CdTe QDs, we explored the protective effects of three treatments, i.e. resveratrol, H₂S and thermotherapy at 43°C, against the cell apoptosis elicited by CdTe QDs. The results showed that resveratrol, H₂S and thermotherapy at 43°C were capable of attenuating cell apoptosis and intercellular ROS production through inhibiting signal pathways of Akt, p38 and JNK, respectively. As there is only limited number of exogenous treatments reported to diminish the toxicity of QDs, our findings will provide a novel insight for researchers who try to reduce or even eliminate the adverse health effects of QDs.

The neurotoxicity of iron, copper and cobalt in Parkinson's disease through ROS-mediated mechanisms

Parkinson's disease (PD) is the second most common neurodegenerative disease with gradual loss of dopaminergic neurons. Despite extensive research in the past decades, the etiology of PD remains elusive. Nevertheless, multiple lines of evidence suggest that oxidative stress is one of the common causes in the pathogenesis of PD. It has also been suggested that heavy metal-associated oxidative stress may be implicated in the etiology and pathogenesis of PD. Here we review the roles of redox metals, including iron, copper and cobalt, in PD. Iron is a highly reactive element and deregulation of iron homeostasis is accompanied by concomitant oxidation processes in PD. Copper is a key metal in cell division process, and it has been shown to have an important role in neurodegenerative diseases such as PD. Cobalt induces the generation of reactive oxygen species (ROS) and DNA damage in brain tissues.

Key Role of ROS in the Process of 15-Lipoxygenase/15-Hydroxyeicosatetraenoiccid-Induced Pulmonary Vascular Remodeling in Hypoxia Pulmonary Hypertension

We previously reported that 15-lipoxygenase (15-LO) and its metabolite 15-hydroxyeicosatetraenoic acid (15-HETE) were up-regulated in pulmonary arterial cells from both pulmonary artery hypertension patients and hypoxic rats and that these factors mediated the progression of pulmonary hypertension (PH) by affecting the proliferation and apoptosis of pulmonary arterial (PA) cells. However, the underlying mechanisms of the remodeling induced by 15-HETE have remained unclear. As reactive oxygen species (ROS) and 15-LO are both induced by hypoxia, it is possible that ROS are involved in the events of hypoxia-induced 15-LO expression that lead to PH. We employed immunohistochemistry, tube formation assays, bromodeoxyuridine (BrdU) incorporation assays, and cell cycle analyses to explore the role of ROS in the process of 15-HETE-mediated hypoxic pulmonary hypertension (HPH). We found that exogenous 15-HETE facilitated the generation of ROS and that this effect was mainly localized to mitochondria. In particular, the mitochondrial electron transport chain and nicotinamide-adenine dinucleotide phosphate oxidase 4 (Nox4) were responsible for the significant 15-HETE-stimulated increase in ROS production. Moreover, ROS induced by 15-HETE stimulated endothelial cell (EC) migration and promoted pulmonary artery smooth muscle cell (PASMC) proliferation under hypoxia via the p38 MAPK pathway. These results indicated that 15-HETE-regulated ROS mediated hypoxia-induced pulmonary vascular remodeling (PVR) via the p38 MAPK pathway.

Dioscin alleviates BDL- and DMN-induced hepatic fibrosis via Sirt1/Nrf2-mediated inhibition of p38 MAPK pathway

Oxidative stress is involved in hepatic stellate cells (HSCs) activation and extracellular matrix overproduction. We previously reported the promising effects of dioscin against CCl4-induced liver fibrosis, but its effects and mechanisms on BDL- and DMN-induced liver fibrosis remain unknown. The results in the present study indicated that dioscin significantly inhibited HSCs activation and attenuated hepatic fibrosis in rats. Furthermore, dioscin markedly up-regulated the levels of sirtuin 1 (Sirt1), HO-1, GST, GCLC and GCLM via increasing the nuclear translocation of nuclear erythroid factor 2-related factor 2 (Nrf2), which in turn inhibited mitogen-activated protein kinase 14 (p38 MAPK) phosphorylation and reduced the levels of COL1A1, COL3A1, α-SMA and fibronectin. These results were further validated by knockdown of Sirt1 and Nrf2 using siRNAs silencing, and abrogation of p38 MAPK using SB-203580 (a p38 MAPK inhibitor) in HSC-T6 and LX-2 cells. Collectively, our findings confirmed the potent effects of dioscin against liver fibrosis and also provided novel insights into the mechanisms of this compound as a candidate for the prevention of liver fibrosis in the future.

A comparative immunological analysis of CoCl2 treated cells with in vitro hypoxic exposure

The hypoxic preconditioning of mammalian cells has been shown to have beneficial effects against hypoxic injuries. However, very little information is available on the comparative analysis of immunological responses to hypoxic and hypoxia mimetic exposure. Therefore, in the present study, mouse peritoneal macrophages and splenocytes were subjected to hypoxia exposure (0.5 % O2) and hypoxia mimetic Cobalt chloride (CoCl2) treatment to evaluate their effect on immune response and delineate the underlying signaling mechanisms. The results obtained indicated that super oxide generation increased while TLR4 expression and cell surface markers like CD25, CD40 and CD69 were suppressed in both the treatments as compared to normoxia. Cobalt chloride treatment increased NF-κB expression, nitric oxide (NO) and iNOS expression, cytokines TNF-α and IL-6 as compared to hypoxia exposure. Our study showed that CoCl2 stabilizes HIF-1α to create hypoxia like conditions but it mainly influences the inflammatory response via NF-κB signaling pathway by skewing the production of proinflammatory molecules like TNF-α, IL-6 and NO.

Protective effect of Xuebijing injection on paraquat-induced pulmonary injury via down-regulating the expression of p38 MAPK in rats

Background

Exposure to paraquat results in acute lung injury. A systemic inflammatory response has been widely established as a contributor to paraquat-induced acute lung injury. Recent studies have reported that consumption of Xuebijing prevents inflammatory response-induced diseases. This study investigated whether consumption of Xuebijing protected rats against paraquat-induced acute lung injury.

Methods

Adult male Sprague Dawley rats were randomly divided into four groups: control group; paraquat group; paraquat + Xuebijing group; and paraquat + dexamethasone group. Rats in the paraquat, paraquat + Xuebijing and paraquat + dexamethasone groups were intraperitoneally injected with paraquat (30 mg/kg) or administered paraquat and Xuebijing at 8 mL/kg or dexamethasone at 5 mg/kg, respectively, via an injection into the tail vein. Lung p38 MAPK, NF-κB65, IkB, p-IκB-α, HIF-1α, Nrf2 and TGF-β1 expression were essayed using western blotting. IL-6, TNF-α, IL-1β, IL-10, TGF-β1 and PIIIP were measured using ELISA. ROS, oxidised glutathione and glutathione activity were measured.

Results

After inducing acute lung injury with paraquat for 24 h, Xuebijing was observed to block lung p-p38 MAPK, NF-κB65, HIF-1α, p-IκB-α and TGF-β1 expression, and increased Nrf2 and IkB expression. The numbers of neutrophils and lymphocytes and total number of cells were significantly lower in the Xuebijing group compared with the control group. IL-6, TNF-α, IL-1β, TGF-β1 and PIIIP levels were significantly decreased in the Xuebijing group. ROS and oxidised glutathione activity were markedly inhibited by Xuebijing. Histological evaluation showed attenuation of the effects of Xuebijing on paraquat-induced lung injury. Compared with the paraquat + dexamethasone group, the Xuebijing + paraquat group showed no significant differences.

Conclusions

Inhibiting the expression of p38 MAPK and NF-κB65 was crucial for the protective effects of Xuebijing on paraquat-induced acute lung injury. The findings suggest that Xuebijing could effectively ameliorate paraquat-induced acute lung injury in rats. Xuebijing was as effective as dexamethasone at improving paraquat-induced lung injury by regulating lung inflammation, lung function and oxidative stress responses.

Effect of intermittent hypoxia on neuro-functional recovery post brain ischemia in mice

Intermittent hypoxia was a simulation of a high-altitude environment. Neuro-inflammation post brain ischemia was considered as a vital impact which contributed to cognitive-functional deficit. The isoform of nitric oxide synthase (iNOS) was an inflammation factor secreted by microglias in neuro-inflammation. In this study, we established a high-altitude environment as the hypoxic condition. Twenty mice were selected and randomized into a hypoxia group (n = 10) or a normoxia group (n = 10) post three vessel occlusion-induced brain ischemia. An enhancement of cognitive-functional recovery was presented in the hypoxia group by survival neuron counting and revealed by the Morris water maze test. Meanwhile, a high level of hypoxia-inducable factor 1 (HIF-1) expression associated with a lower expression of iNOS was observed in the border between infarcts and normal tissue of the hippocampus in the hypoxia group. However, these phenomenons were blocked by HIF-1 inhibition. This suggested that the acceleration of cognitive-functional recovery induced by intermittent hypoxia may depend on HIF-1 activating. An imitation of the hypoxic condition with or without HIF-1 inhibition was operated on the BV-2 cell. A high level of HIF-1 expression associated with a lower-level expression of iNOS was performed in the hypoxic condition. These data suggested that intermittent hypoxia can accelerate cognitive function recovery through attenuating neuro-inflammation.

Rosmarinic acid inhibits chemical hypoxia-induced cytotoxicity in primary cultured rat hepatocytes

We examine the effect of rosmarinic acid (RA) in chemical hypoxia-induced injury in rat hepatocytes. Cell viability was significantly decreased by cobalt chloride (CoCl2), a well-known hypoxia mimetic agent in a time- and dose- dependent manner. RA pretreatment before exposure to CoCl2 significantly attenuated the CoCl2-induced decrease of cell viability. Additionally, pretreatment with RA potentiated the decrease of Bcl-2 expression and attenuated the increase of Caspase-3 expression by CoCl2. CoCl2 treatment resulted in an increase of intracellular ROS generation, which is inhibited by RA or N-acetyl-cysteine (NAC, a ROS scavenger), and p38MAPK phosphorylation, which is also blocked by RA or NAC. CoCl2-induced increase of Bax/Bcl-2 ratio and Caspase-3 expression was attenuated by RA, NAC and SB203580 (p38MAPK inhibitor). CoCl2-induced decrease of cell viability was also attenuated by RA, NAC and SB203580 pretreatment. Additionally, RA inhibited CoCl2-induced COX-2 expression and prostaglandin E2 (PGE2) secretion. Similar to the effect of RA, both NAC and NS-398 (COX-2 inhibitor) blocked CoCl2-induced COX-2 expression and PGE2 secretion. NS-398 attenuated not only CoCl2-induced increase of Bax/Bcl-2 ratio and Caspase-3 expression, but decrease of cell viability. Taken together, RA protects primary cultured rat hepatocytes against CoCl2-induced cell injury through inhibition of ROS-activated p38MAPK and COX-2/PGE2 pathway.

Therapeutic benefits of H₂S in Alzheimer's disease

Hydrogen sulfide (H2S), an endogenously generated gaseous mediator, has been discovered to regulate a series of physiological and pathological processes in mammalian systems. In recent decades scientific interest has grown in the physiological and pathological implications of H2S, specifically its role in the central nervous system (CNS). H2S can work in the CNS as a neuromodulator to promote long-term potentiation and regulate intracellular calcium concentration and pH level in brain cells. H2S may protect the nervous system from oxidative stress, apoptosis, or degeneration. The aim of this review is to present the current understanding of H2S as a potential agent for the treatment of Alzheimer's disease (AD). Dysregulation of H2S homeostasis is implicated in the pathological processes of AD. Substantial evidence from both in vivo and in vitro studies shows that H2S prevents neuronal impairment and attenuates cognitive dysfunction in the experimental model of AD. The mechanisms underlying the protective role of H2S in AD involve its antioxidant, anti-apoptotic, and anti-inflammatory effects. We conclude that H2S has potential therapeutic value for the treatment of AD.