Morin hydrate protects type-2-diabetic wistar rats exposed to diesel exhaust particles from inflammation and oxidative stress.

Background: Studies have demonstrated that exposure to diesel exhaust particle (DEP) aggravates diabetes condition by inducing oxidative and pro-inflammatory effects. Morin hydrate (MH), a flavonol found in common guava, among others has been demonstrated to possess a variety of biological activities. The present study was designed to investigate the effects of morin hydrate (MH) on the pancreas of type-2 diabetic (T2D) wistar rats exposed to DEP. Methods: Rats were induced with type 2 diabetes by oral fructose therapy for 14 days followed by injection of streptozotocin (45 mg/kg). These rats were pre-treated with DEP (0.4 mg/kg and 0.5 mg/kg) through nasal instillation prior to receiving oral MH (30 mg/kg).This study determined oxidative stress parameters using biochemical assay, and some pancreatic genes involved in oxidative stress, inflammation and glucose uptake were quantified using RT-polymerase chain reaction (PCR). Results: The results indicate that MH reverses oxidative stress in T2D rats exposed to DEP via substantial increase in superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity and reduced glutathione (GSH) levels, but a decrease in malondialdehyde (MDA) and conjugated diene (CD) levels. Moreover, PCR assay showed that MH mitigate inflammation and oxidative stress but promote glucose uptake by increasing the mRNA expression of IL-10, HO-1, and GLUT 4; decreasing mRNA expression of IL-1 and modulating AKT/PI3K/GLUT4 and AMPK/GLUT4 signaling. Histopathological examination revealed that MH reverses DEP induced pancreatic fibrosis and necrosis. Conclusion: The results suggest that MH alleviate inflammation and oxidative stress and promote glucose uptake in the pancreas of type-2 diabetic rats, either in the presence or absence of DEP.

The modulatory effects of alkaloid extracts of Cannabis sativa, Datura stramonium, Nicotiana tabacum and male Carica papaya on neurotransmitter, neurotrophic and neuroinflammatory systems linked to anxiety and depression.

This study investigated the modulatory effects of alkaloid extracts of Cannabis sativa (CSAE), Datura stramonium (DSAE), Nicotiana tabacum (NTAE) and male Carica papaya (CMAE) on neurotransmitter, neurotrophic and neuro-inflammatory systems linked to anxiety and depression. Male Wistar rats were orally administered the alkaloid extracts in doses of 5, 50, 500, and 2000 mg/kg for 90 days. On day 91, neurobehavioural studies were evaluated, rats were sacrificed, brain hippocampus removed and tissue homogenate prepared. Biochemical, cytokine and neurotransmitter metabolisms were estimated in the hippocampus. Expressions of genes linked to anxiety and depression were evaluated by RT-qPCR. Results showed CSAE, NTAE and CMAE act as anxiolytic and antidepressant agents by depleting TNF-α, IL-1ß and reactive oxygen species concentrations, and monoamine oxidase, angiotensin 1-converting enzyme and acetylcholinesterase activities while elevating IL-10 and dopamine concentrations and glutamate dehydrogenase activity at doses of 5, 50 and 500. Same doses of CSAE, NTAE and CMAE also depleted the gene expressions of GSK3ß, JNK, NF-ĸB, and Nesfatin-1 while increasing expressions of CREB, BDNF, serotonin and Nrf2. However, administration of DSAE and 2000 mg/kg CSAE, NTAE and CMAE had adverse modulatory effects on the neurochemical concentrations and activities as well as the gene expressions of the evaluated neurotransmitter, neurotrophic and inflammatory systems. In conclusion, the study established the sub-chronic instrumentalization potential of CSAE, CMAE, and NTAE for anxiolytic and anti-depressive moods, though their use may be associated with dependence and addiction, which may result in more detrimental effects than any therapeutic potential they may proffer.

Neuroprotective effects of catechin and quercetin in experimental Parkinsonism through modulation of dopamine metabolism and expression of IL-1ß, TNF-α, NF-κB, IκKB, and p53 genes in male Wistar rats.

The neurobehavioral, brain redox-stabilizing and neurochemical modulatory properties of catechin and quercetin in rotenone-induced Parkinsonism, and the involvement of NF-κB-mediated inflammation, were investigated. Male Wistar rats subcutaneously administered with multiple doses of 1.5 mg/kg rotenone were post-treated with 5-20 mg/kg catechin or quercetin. This was followed by neurobehavioral evaluation, biochemical estimations, and assessment of neurotransmitter metabolism in the striatum. Expression of genes involved in the canonical pathway for the activation of NF-κB mediated inflammation (IL-1ß, TNF-α, NF-κB, and IκKB) and the pro-apoptotic gene, p53, in the striatum was determined by RT-qPCR. Catechin and quercetin mitigated neurobehavioral deficits caused by rotenone. Both flavonoids attenuated striatal redox stress and neurochemical dysfunction, optimized disturbed dopamine metabolism, and improved depletion of neuron density caused by rotenone toxicity. While administration of catechin produced a more pronounced attenuating effect on IL-1ß, TNF-α, and p53 genes, the attenuating effect of quercetin (20 mg/kg) was more pronounced on NF-κB and IκKB gene expressions when compared to the group administered with rotenone only. Comparatively, quercetin demonstrated superior protection against rotenone neurotoxicity. It is concluded that catechin and quercetin have potential relevance in Parkinson's disease therapy through amelioration of redox stress, optimization of dopamine metabolism, and modulation of anti-inflammatory and anti-apoptotic pathways.

Hesperetin protects against diesel exhaust particles-induced cardiovascular oxidative stress and inflammation in Wistar rats.

Air particulate matter exposure has been linked to cardiovascular and atherosclerosis as a result of increase oxidative stress and inflammatory response. This study aims to determine the effect of the use of hesperetin (HESP) as a therapeutic agent to mitigate the cardiovascular oxidative and pro-inflammatory effects of diesel exhaust particles in Wistar rats. DEP was collected from an Iveco cargo engine truck, and n-hexane fraction (hDEP) was obtained. Forty Wistar strains of male albino rats (6 weeks) were divided into 8 groups: control group received DMSO and CMC-Na; other groups received either n-hexane extract of DEP (0.064 or 0.640 mg/kg hDEP) or Standard Reference Material 2975 (0.064 mg/kg hSRM) in the presence or absence of 200 mg/kg HESP. Extracts were administered orally. Serum lipids, lipid peroxidation (LPO), conjugated dienes (CDs), and GSH levels were determined. Also, inflammatory cytokines, PCSK-9, LDL-receptor, and antioxidant genes expression were assessed by RT-PCR in both the heart and aorta. The molecular interaction of targeted proteins with HESP was assessed by the in silico approach. Extracts of DEP caused a significant (p < 0.001) increase in serum lipids but significantly decreased HDL-CHOL. It also increased CDs and MDA levels but decreased GSH levels. In addition, the particulate extracts caused a significant (p < 0.001) increase in pro-inflammatory genes expression in the heart and aorta but significantly decreased IL-10 and LDL-R gene expressions. Pre-treatment with hesperetin significantly reversed all these effects. This study shows that hesperetin has the ability to protect against DEP-induced oxidative stress and inflammation in the cardiovascular system.

Dihydroquercetin improves rotenone-induced Parkinsonism by regulating NF-κB-mediated inflammation pathway in rats.

This study examined the effect of dihydroquercetin (DHQ), also knofigurewn as taxifolin, on rotenone-induced Parkinsonism in rats. Male Wistar rats were administered 1.5 mg/kg rotenone for 10 days and subsequently treated with 0.25-1.0 mg/kg DHQ for 3 days followed by the assessment of parkinsonian symptoms. Brain striatal redox stress and neurochemical dysfunction markers were assessed spectrophotometrically. Histopathological evaluation of the striatum was done by hematoxylin and eosin staining technique. The expression of genes involved in the activation of NF-κB signaling pathway (IL-1ß, TNF-α, NF-κB and IκKB), and the p53 gene in the striatum were determined by RT-qPCR. DHQ attenuated parkinsonian symptoms as well as striatal redox stress, neurochemical dysfunction, and histological alterations occasioned by rotenone toxicity. Importantly, DHQ significantly suppressed the rotenone-induced upregulation of IL-1ß, NF-κB, and IκKB expression (p < 0.05) in the striatum of parkinsonian rats. DHQ demonstrated notable neurotherapeutic potential against rotenone-induced Parkinsonism in rats by improving parkinsonian symptoms (bradykinesia, catalepsy, postural instability, impaired locomotor behavior, and tremor) and neurochemical dysfunctions via modulation of genes involved in the activation of the canonical pathway of NF-κB-mediated inflammation.

The cardiovascular protective effects of rooibos (Aspalathus linearis) extract on diesel exhaust particles induced inflammation and oxidative stress involve NF-κB- and Nrf2-dependent pathways modulation.

Studies have shown that diesel exhaust particles (DEP) induced oxidative stress and inflammation. This present study examined the molecular effects of aqueous rooibos extract (RE) on the cardiovascular toxic effect of methanol extract of DEP in exposed Wistar rats. The results showed that DEP caused significant (p < 0.001) increase in MDA and CDs levels in the aorta and heart but this increase was significantly (p < 0.001) attenuated by rooibos extract. DEP induced IL-8, TNFα, IL-1ß and decreased IL-10 gene expressions, all of which were reversed in the presence of rooibos extract. The expression of NF-κB, and IκKB genes were also significantly (p < 0.001) induced by DEP in both tissues, but pre-treatment with RE attenuated these effects. In contrast, DEP repressed IκB mRNA level, which was significantly (p < 0.001) reversed by rooibos extract pre-treatment. In addition, pre-treatment with rooibos extract attenuated the increased Nrf2 and HO-1 mRNA levels caused by DEP. This indicates the potential of rooibos extract to protect against DEP-induced cardiovascular toxicity.

Rooibos (Aspalathus linearis) and honeybush (Cyclopia species) modulate the oxidative stress associated injury of diesel exhaust particles in human umbilical vein endothelial cells.

BACKGROUND: Previous evidence show foods and beverages rich in polyphenolic compounds to have favourable effects on the cardiovascular system. HYPOTHESIS: The current study assessed the modulation of oxidative stress and associated inflammation induced by diesel exhaust particles (DEP - SRM 2975) by pre-treatment of human umbilical vein endothelial cells (HUVECs) with aqueous extracts of rooibos [fermented (FR) as well as green form (GR)] and honeybush [fermented form (FH)]. STUDY DESIGN: HUVEC are either exposed to DEP (10 µg/ml) for 4 h or pre-treated with 40 and 60 µg/ml of FR or GH or FR, or 50 µg/ml orientin (OR) for 6 h prior to DEP exposure. METHODS: In vitro antioxidant capacity of the extracts was assessed and the polyphenol contents were also assessed by HPLC. ROS, cell viability, lactate dehydrogenase leakage, lipid peroxidation, GSH:GSSG ratios, conjugated diene and protein carbonyl levels were determined as indices of oxidative stress and cytotoxicity. RT-qPCR and western blot were used to assess inflammatory cytokines and antioxidant genes expression. RESULTS: DEP caused a dose and time-dependent increase in ROS production, significant (p < 0.001) increase in protein carbonyl (PC) formation, thiobarbituric acid reactive substances and conjugated dienes levels (p < 0.01) and a significant reduction in glutathione (GSH) redox status. Pre-incubation with either the herbal extracts or orientin attenuated these effects. The significant increase in IL-1α, IL-6, IL-8, VCAM-1 and ATF4 gene expression caused by DEP (10 µg/ml) were also attenuated by the presence of the FR, GR and FH extracts, and OR . Pre-treatment with the rooibos extracts or flavone orientin enhanced cell viability, reduced LDH leakage, enhanced mRNA expression of NQO1 and Nrf2, but repressed CYP1B1 mRNA induced by DEP. Western blot showed both the herbal tea extracts and orientin to enhance NQO1 and γGSC protein induction by DEP. CONCLUSION: Taken together, the herbal extracts offer protection against DEP-induced oxidative stress and inflammatory response.

Myeloid HO-1 modulates macrophage polarization and protects against ischemia-reperfusion injury.

Macrophages polarize into heterogeneous proinflammatory M1 and antiinflammatory M2 subtypes. Heme oxygenase 1 (HO-1) protects against inflammatory processes such as ischemia-reperfusion injury (IRI), organ transplantation, and atherosclerosis. To test our hypothesis that HO-1 regulates macrophage polarization and protects against IRI, we generated myeloid-specific HO-1-knockout (mHO-1-KO) and -transgenic (mHO-1-Tg) mice, with deletion or overexpression of HO-1, in various macrophage populations. Bone marrow-derived macrophages (BMDMs) from mHO-1-KO mice, treated with M1-inducing LPS or M2-inducing IL-4, exhibited increased mRNA expression of M1 (CXCL10, IL-1ß, MCP1) and decreased expression of M2 (Arg1 and CD163) markers as compared with controls, while BMDMs from mHO-1-Tg mice displayed the opposite. A similar pattern was observed in the hepatic M1/M2 expression profile in a mouse model of liver IRI. mHO-1-KO mice displayed increased hepatocellular damage, serum AST/ALT levels, Suzuki's histological score of liver IRI, and neutrophil and macrophage infiltration, while mHO-1-Tg mice exhibited the opposite. In human liver transplant biopsies, subjects with higher HO-1 levels showed lower expression of M1 markers together with decreased hepatocellular damage and improved outcomes. In conclusion, myeloid HO-1 expression modulates macrophage polarization, and protects against liver IRI, at least in part by favoring an M2 phenotype.

Diesel Exhaust Particles and the Induction of Macrophage Activation and Dysfunction.

Diesel exhaust particles (DEP) are an important component of air particulate matter, generated from the incomplete combustion of fossil fuel in diesel engines. Several epidemiological and experimental data have shown the ability of DEP to induce oxidative stress and pro-inflammatory response as mechanisms in macrophage activation and dysfunction. Macrophages are very important to immunity and immune response due to their ability to phagocyte microbes and parasites. They also respond to toxic chemicals, such as DEP, in the environment and studies have shown that their functions may be impaired by their exposure to DEP. For instance, the ultrafine particles (UFP) of DEP are capable of penetrating deep into the lungs and getting deposited in the alveolar component, where they can mitigate against the phagocytosis function of the alveolar macrophages. In this review, data linking DEP exposure to macrophage activation and dysfunction are addressed together with the various mechanisms involved in these DEP-induced effects.

Air particulate matter induced oxidative stress and inflammation in cardiovascular disease and atherosclerosis: The role of Nrf2 and AhR-mediated pathways.

Air particulate matter (PM) is an important component of air pollution, which has been reported to play important role in the adverse health effects of the latter. Extensive experimental data and epidemiological studies have shown that the increased cardiovascular morbidity and mortality and atherosclerosis caused by air pollution are mainly due to the PM component. Implicated in these adverse health effects of PM, is their ability to induce oxidative stress and pro-inflammatory events in the vascular system. The association between the cardiovascular ischemic events and atherosclerosis induced by PM has been linked to the ultrafine and fine components. These particles have a high content of redox cyclic chemicals. This, together with their ability to combine with proatherogenic molecules enhanced tissue oxidative stress. Studies have shown that the oxidative stress induced by PM could up-regulates the expression of phase I and phase II metabolize enzymes. This up-regulation occurs by the activation of transcription factors (such as nuclear factor (erythroid-derived 2) -like 2-related factor (Nrf2) and aryl hydrocarbon receptor (AhR)). This review will focus on data supporting the role of oxidative stress and inflammation in PM-induced cardiovascular diseases and atherosclerosis and the importance of Nrf2-and AhR- dependent regulatory pathways in the PM-induced cardiovascular events and atherosclerosis.

Heme oxygenase-1 attenuates cadmium-induced mitochondrial-caspase 3- dependent apoptosis in human hepatoma cell line.

BACKGROUND: Cadmium (Cd) is a well known environmental and industrial toxicant causing damaging effects in numerous organs. In this study, we examined the role of heme oxygenase-1 (HO-1) in modulating the Cd-induced apoptosis in human hepatoma (HepG2) cells after 24 h exposure. METHODS: HepG2 cells were exposed to 5 and 10 µM Cd as CdCl2 for 24 h while other sets of cells were pre-treated with either 10 µM Cobalt protoporphyrin (CoPPIX) or 10 µM Tin protoporphyrin (SnPPIX) for 24 h, or 50 µM Z-DEVD-FMK for 1 h before exposure to 5 and 10 µM CdCl2 for 24 h. Expressions of caspase 3, cytosolic cytochrome c, mitochondrial Bax and anti-apoptotic BCL-xl proteins were assessed by western blot. Intracellular reactive oxygen species (ROS) production was determined using the dihydrofluorescein diacetate (H2DFA) method. Cell viability was assessed by MTT assay, while a flow cytometry method was used to assess the level of apoptosis in the cell populations. RESULTS: Our results show that there were a significant increase in the expression of cytosolic cytochrome c, mitochondrial Bax protein, and caspase 3 at 5 and 10 µM compared to the control, but these increases were attenuated by the presence of CoPPIX. The presence of SnPPIX significantly enhanced Cd-induced caspase 3 activities. CoPPIX significantly decreased the level of ROS production by 24.6 and 22.2 % in 5 and 10 µM CdCl2, respectively, but SnPPIX caused a significant increase in ROS production in the presence of CdCl2. HepG2 cell viability was also significantly impaired by 13.89 and 32.53 % in the presence of 5 and 10 µM CdCl2, respectively, but the presence of CoPPIX and Z-DEVD-FMK significantly enhanced cell survival, while SnPPIX enhanced Cd-impaired cell viability. The presence of CoPPIX and Z-DEVD-FMK also significantly decreased the population of apoptotic and necrotic cells compared with Cd. CONCLUSION: In summary, the present study showed that HO-1 attenuates the Cd-induced caspase 3 dependent pathway of apoptosis in HepG2 cells, probably by modulating Cd-induced oxidative stress.

Diesel exhaust particulate increases the size and complexity of lesions in atherosclerotic mice.

OBJECTIVE: Diesel exhaust particulate (DEP), a major component of urban air pollution, has been linked to atherogenesis and precipitation of myocardial infarction. We hypothesized that DEP exposure would increase and destabilise atherosclerotic lesions in apolipoprotein E deficient (ApoE-/-) mice. METHODS: ApoE-/- mice were fed a 'Western diet' (8 weeks) to induce 'complex' atherosclerotic plaques, with parallel experiments in normal chow fed wild-type mice. During the last 4 weeks of feeding, mice received twice weekly instillation (oropharyngeal aspiration) of 35 µL DEP (1 mg/mL, SRM-2975) or vehicle (saline). Atherosclerotic burden was assessed by en-face staining of the thoracic aorta and histological examination of the brachiocephalic artery. RESULTS: Brachiocephalic atherosclerotic plaques were larger in ApoE-/- mice treated with DEP (59 ± 10%) than in controls (32 ± 7%; P = 0.017). In addition, DEP-treated mice had more plaques per section of artery (2.4 ± 0.2 vs 1.8 ± 0.2; P = 0.048) and buried fibrous layers (1.2 ± 0.2 vs 0.4 ± 0.1; P = 0.028). These changes were associated with lung inflammation and increased antioxidant gene expression in the liver, but not with changes in endothelial function, plasma lipids or systemic inflammation. CONCLUSIONS: Increased atherosclerosis is caused by the particulate component of diesel exhaust producing advanced plaques with a potentially more vulnerable phenotype. These results are consistent with the suggestion that removal of the particulate component would reduce the adverse cardiovascular effects of diesel exhaust.

Phospholipase C mediates cadmium-dependent apoptosis in HEK 293 cells.

Cadmium is a heavy metal that is known to cause toxicity to cells and, at low concentrations, can initiate apoptosis. This study was undertaken with the aim of defining the role of phospholipase C (PLC) in mediating cadmium-induced apoptosis in human embryonic kidney (HEK 293) cells. We have shown that intracellular Ca(2+) levels increased significantly in HEK 293 cells after 24-hr exposure to Cd. The activity of the calcium-dependent protease calpain rose by four times. The PLC-specific inhibitor, U73122, prevented the Cd-dependent increase in Ca(2+) levels and also abolished Cd-dependent calpain and caspase 3 activation as well as Cd-dependent mitochondrial Bax accumulation. Inhibition of PLC also leads to an increased cell viability following exposure to Cd. Taken together, the results show that the PLC pathway is involved in mediating Cd-induced apoptosis in HEK 293 cells.

The chemopreventive effects of aged garlic extract against cadmium-induced toxicity.

Garlic has been reported in many previous studies as a potent chemopreventive agent. The protective effect of garlic has been ascribed to the presence of organosulphur compounds (OSC). In this study, the efficacy of aged garlic extract (AGE) compared to diallyl disulfide (DADS) in protecting against toxicity induced by cadmium (Cd) in 1321N1 and HEK293 cells was investigated. The involvement of the transcription factor Nrf2 in this protection was also examined. The results show that AGE significantly prevented loss of cell viability in Cd-treated 1321N1 and HEK293 cells. In comparison DADS had no significant effect in protecting HEK293 cells but did protect 1321N1 cells. AGE significantly reduced Cd-induced TBARS production and LDH leakage in the two cell lines, and AGE and DADS both increased GSH levels in Cd-treated cell lines. Pre-treatment of cells with AGE or DADS increased expression of the protective enzyme NAD(P)H:quinone oxidoreductase (NQO1), and this was associated with the accumulation of the transcription factor Nrf2. These results show that AGE and DADS have beneficial effects against Cd-induced toxicity, and this protection appears to be mediated via induction of cytoprotective enzymes in an Nrf2-dependent manner. This indicates the potential for using AGE as a chemoprevention strategy for Cd toxicity.

Nrf2-mediated adaptive response to cadmium-induced toxicity involves protein kinase C delta in human 1321N1 astrocytoma cells.

Cadmium (Cd) is a toxic heavy metal, and exposure to Cd causes a range of changes within the cell. At high concentrations, Cd causes damage to cells via a range of mechanisms. At low concentrations, Cd can stimulate expression of genes that are part of an adaptive response. In this study, we have used the astrocytoma cell line 1321N1 as a model to investigate the induction of protective enzymes in response to Cd. We have shown that expression of NAD(P)H:quinone oxidoreductase and haem oxygenase enzymes are induced as the protein level by -fold and -fold, and in response to 5 and 10 µM Cd. Levels of NQO1 and HO1 mRNA are also increased by -fold and -fold following 24h exposure to 5 and 10 µM cadmium. An increase in the nuclear accumulation of the transcription factor Nrf2 was also observed following Cd treatment. Through the use of the protein kinase C inhibitor bisindolylmaleimide (VIII) acetate we have demonstrated the involvement PKC in the Nrf2-mediated response of 1321N1 cells to 5-10 µM Cd. We have also shown through the used of 10 µM rottlerin that PKCδ is the isoform responsible for mediating this response.

Dual Path Platform HIV 1/2 assay: evaluation of a novel rapid test using oral fluids for HIV screening at the National Hospital in Abuja, Nigeria.

HIV/AIDS disease is endemic in Nigeria and associated with stigmatization. Availability of a reliable rapid testing kit and procedure will increase uptake of services. The study aimed to determine the correlation between detection of HIV antibodies in blood to that in oral fluid and to determine the sensitivity and specificity of the Dual Path Platform (DPP) testing kit using oral fluid samples. HIV antibodies detected in oral mucosa transudate and whole capillary blood from HIV-positive, high-risk and low-risk participants were compared with results obtained with whole venous blood from the same participants tested with Determine and Western blot (for discordant cases). Oral fluid test has sensitivity and specificity of 100% relative to Determine rapid assay, while whole capillary blood test has sensitivity of 100% and specificity of 99.5%. DPP oral fluid test is a reliable point-of-care test and may be deployed in large-scale screening exercises.