Porphyrogenic effects and induction of heme oxygenase in vivo by δ-aminolevulinic acid

The effects of single large doses of the porphyrin-heme precursor ?d-aminolevulinic acid on tissue porphyrins and on δ-aminolevulinate synthase and heme oxygenase, the rate-living enzymes of liver heme synthesis and degradation respectively, were studied in the chick embryo in ovo, in the mouse and in the rat. δ-Aminolevulinic acid treatment produced a distinctive pattern characterized by extensive tissue porphyrin accumulation and alterations in these rate-limiting enzymes in the liver. Repression of basal or allylisopropylacetamide-induced liver δ-aminolevulinate synthase was observed and, in the mouse and the rat, induction of liver heme oxygenase after δ-aminolevulinic acid treatment, in a manner similar to the known effects of hemin on these enzymes. In the chick embryo liver in ovo heme oxygenase was substantially higher than in rat and mouse liver, and was not significantly induced by δ-aminolevulinic acid or other compounds, including hemin, CS₂ and CoCl₂. Levulinic acid, an analogue of δ-aminolevulinic acid, did not induce heme oxygenase in mouse liver. δ-Aminolevunilic acid treatment did not impair ferrochelatase activity but was associated with slight and variable decreases in liver cytochrome P-450. Treatment of chick embryos with a small ‘priming’ dose of 1,4-dihydro-3,5-dicarbethoxycollidine, which impairs liver ferrochelatase activity, accentuated porphyrin accumulation after δ-aminolevulinic acid in the liver. These observations indicate that exogenous δ-aminolevulinic acid is metabolized to porphyrins in a number of tissues and, at least in the liver, to a physiologically significant amount of heme, thereby producing an increase in the size of one or more of the heme pools that regulate both heme systhesis and degradation. It is also possible than when δ-aminolevulinic acid is markedly overproduced in vivo it may be transported to many tissues and re-enter the heme pathway and alter porphyrin-heme metabolism in cells and tissues other than those in which its overproduction primarily occurs.     

Involvement of nitric oxide with activation of Toll-like receptor 4 signaling in mice with dextran sodium sulfate-induced colitis

Ulcerative colitis is an inflammatory bowel disease characterized by acute inflammation, ulceration, and bleeding of the colonic mucosa. Its cause remains unknown. Increases in adhesion molecules in vascular endothelium, and activated neutrophils releasing injurious molecules such as reactive oxygen species, are reportedly associated with the pathogenesis of dextran sodium sulfate (DSS)-induced colitis. Nitric oxide (NO) production derived from inducible NO synthase (iNOS) via activation of nuclear factor κB (NF-κB) has been reported. It is also reported that stimulation of Toll-like receptor 4 (TLR4) by lipopolysaccharide can activate NF-κB. In this study, we investigated the involvement of NO production in activation of the TLR4/NF-κB signaling pathway in mice with DSS-induced colitis. The addition of 5% DSS to the drinking water of male ICR mice resulted in increases in TLR4 protein in colon tissue and NF-κB p65 subunit in the nuclear fraction on day 3, increases in colonic tumor necrosis factor-α on day 4, and increases in P-selectin, intercellular adhesion molecule-1, NO₂⁻/NO₃⁻, and nitrotyrosine in colonic mucosa on day 5. These activated inflammatory mediators and pathology of colitis were completely suppressed by treatment with a NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, as well as an iNOS inhibitor, aminoguanidine. Conversely, a NO-releasing compound, NOC-18, increased TLR4 levels and nuclear translocation of NF-κB p65 and exacerbated mucosal damage induced by DSS challenge. These data suggest that increases in TLR4 expression induced by drinking DSS-treated water might be directly or indirectly associated with NO overproduction.     

3,5-Dicaffeoyl-4-malonylquinic acid reduced oxidative stress and inflammation in a experimental model of inflammatory bowel disease

Abstract

Aim: The aim of the present study was to examine the effects of 3,5-dicaffeoyl-4-malonylquinic acid (CA1), extract from Centella Asiatica, in rats subjected to experimental colitis.

Results: Colitis was induced in rats by intracolonic instillation of dinitrobenzene sulphonic acid (DNBS). CA1 was administered daily orally (0.2 or 2 mg/kg). Four days after DNBS administration, treatment with CA1 significantly reduced the appearance of diarrhoea and the loss of body weight. This was associated with a significant reduction in colonic MPO activity. CA1 also reduced NF-κB activation, the pro-inflammatory cytokines release, the appearance of I-NOS, nitrotyrosine, PARP and proMMP-9 and -2 activity in the colon and reduced the up-regulation of ICAM-1 and the expression of P-Selectin.

Conclusions: The results of this study suggested that administration of CA1 may be beneficial for treatment of inflammatory bowel disease.     

Betulinic acid inhibits cell proliferation,migration, and inflammatory response in rheumatoid arthritis fibroblast-like synoviocytes

Betulinic acid (BA), a pentacyclic triterpene derived from the bark of the white birch tree, has been reported to have a variety of pharmacological effects, including antioxidant, anti-inflammatory, antitumor, immunomodulatory, and antiarthritis properties. However, the role of BA in rheumatoid arthritis (RA) remains unclear. Thus, the objective of this study was to examine the effects of BA on RA fibroblast-like synoviocytes (RA-FLS) proliferation, migration, and inflammatory response, and further explore the potential underlying mechanisms. Our results showed that BA inhibited the proliferation, migration, and invasion of RA-FLSs. BA also attenuated tumor necrosis factor-α (TNF-α), enhanced matrix metalloproteinases (MMPs) expression, and inflammatory cytokines production in RA-FLS. Furthermore, BA prevented the activation of Akt/NF-κB pathway in RA-FLS exposed to TNF-α. In conclusion, these findings indicated that BA inhibits cell proliferation, migration, and inflammatory response in RA-FLS; and the Akt/NF-κB signaling pathway was involved in the protective effect of BA on RA-FLS. Thus, BA might be a potential therapeutic agent for the treatment of RA.     

Effects of allopurinol on uric acid concentrations,xanthine oxidoreductase activity and oxidative stress in broiler chickens

The purpose of this study was to determine the effects of allopurinol (AL) on xanthine oxidoreductase (XOR) activity and uric acid (UA) levels in chickens. Thirty 5-week-old broilers were divided into three groups and fed 0 (control), 25 (AL25) or 50 (AL50) mg AL per kg of body mass for 5 weeks. Chicks were weighed twice weekly and leukocyte oxidative activity (LOA) and plasma purine levels were determined weekly in five birds per group. Chicks were sacrificed after 2 or 5 weeks, and samples from tissues were taken for analysis of XOR activity. Plasma UA concentrations were lower (P < 0.001) and xanthine and hypoxanthine concentrations were greater (P < 0.001) in AL25 and AL50 birds compared to controls, whereas no differences (P = 0.904) were detected in allantoin concentrations. By week 5, body mass was reduced (P < 0.001) to 84.0 and 65.1% of that in controls for AL25 and AL50 broilers, respectively, and LOA was 4.1 times greater (P < 0.05) in AL25 compared to control birds. Liver XOR activity was increased by 1.1 and 1.2 times in AL25 and AL50 birds, but there was no change (P > 0.05) in XOR activity in the pancreas and intestine. These results suggest that AL effect on XOR activity is tissue dependent.     

不同浓度5-氨基乙酰丙酸(ALA)浸种对NaCl胁迫下番茄种子发芽率及芽苗生长的影响

为探讨外源5-氨基乙酰丙酸(ALA)对NaCl胁迫下番茄种子发芽率及芽苗生长的影响,以‘中杂九号’番茄种子为试材,不同浓度ALA(0、0.1、0.5、1.0、5.0、10.0mg/L)浸种24h后,在0、25、50、100mmol/L NaCl胁迫下,28℃,黑暗培养7d,研究ALA对番茄种子发芽参数(发芽率、发芽势、发芽指数、活力指数、芽苗总鲜重)及胚芽和胚根中的抗氧化酶(超氧化物歧化酶SOD、过氧化物酶POD、过氧化氢酶CAT)活性和丙二醛(MDA)含量的影响.结果表明:非盐胁迫下,ALA浸种使番茄种子的发芽势、发芽指数、活力指数、芽苗总鲜重增加,胚根中SOD、POD活性降低,MDA含量减少;25 mmol/L NaCl胁迫能够提高发芽率、活力指数、芽苗总鲜重,而50-100mmol/L NaCl胁迫极显著的降低发芽率、发芽势、发芽指数、活力指数;0.1-0.5mg/L ALA浸种能够提高NaCl胁迫下番茄种子的发芽率、发芽指数、活力指数、芽苗总鲜重和抗氧化酶活性,降低MDA含量,而高浓度ALA(10.0mg/L)浸种导致发芽率、发芽指数、活力指数降低.总之,ALA浸种能够促进番茄种子萌发和芽苗生长,浸种浓度不宜超过5.0mg/L,NaCl胁迫下以0.1 mg/L ALA浸种处理效果最佳.     

The differential NF-kB modulation by S-adenosyl-L-methionine,N-acetylcysteine and quercetin on the promotion stage of chemical hepatocarcinogenesis

S-adenosylmethionine (SAM), N-acetylcysteine (NAC) and quercetin exhibit a chemoprotective effect. Likely this effect is mediated by counteracting, oxidative stress and NF-kB activation. To test this hypothesis F344 rats were subjected to hepatocarcinogenesis with or without antioxidants. NAC decreased foci in number and area, SAM and quercetin decreased area. Lipid-peroxidation was decreased by antioxidants, but only SAM increased glutathione. SAM, in its regulation from IKK downwards, abolished the NF-kB activation. NAC decreased IKK and IkB-a phosphorylation, and Rel-A/p65 and NF-kB binding, though the last two were affected with less intensity compared to the NF-kB inhibitor. Quercetin decreased Rel-A/p65, without modifying upstream signalling. Although all antioxidants inhibited oxidative stress as shown by reduction of lipid peroxidation, not all exerted the same effect on NF-kB signalling pathway and only SAM increased GSH. The mechanisms exerted by SAM in the reduction of foci makes this compound a potential liver cancer therapeutic agent.     

The effect of Cu,Zn and Fe chelates on the antioxidative status of thigh meat of broiler chickens

The studies aimed to verify the effect of Cu, Zn and Fe glycine chelate on the antioxidative status in the thigh meat of broiler chickens. The study assumption was that due to the antioxidative or prooxidative effect of Cu, Zn and Fe, these elements supplemented to chickens in an easily assimilable form would modify the antioxidative status of meat and those having a prooxidative effect could deteriorate the quality of meat. The experiment involved three hundred and fifty Ross 308 chickens divided into seven equipotent experimental groups. Over 42 days of the experiment, the chickens were administered Cu, Zn and Fe glycine chelates in an amount corresponding to 50% of the requirement (experimental factor I) or 25% of the requirement (experimental factor II). The level of oxidative stress indicators such as superoxide dismutase, catalase, glutathione, glutathione peroxidase and malondialdehyde was determined in the muscles and blood. The groups receiving Zn or Cu chelate showed statistically confirmed higher activity of superoxide dismutase, catalase, and a higher level of glutathione in comparison to the group receiving Fe chelate. In order to increase the antioxidative stability of thigh meat, it is sufficient that broiler chickens receive Zn or Cu in the form of glycine chelate in an amount covering 25% of their requirement of such minerals. On the other hand, the use of Fe glycine chelates decreased antioxidative stability due to an increase in the level of malondialdehyde, so it should be considered whether the administration of pro-oxidative Fe chelate to broilers is advisable.     

circLRP6 regulates high glucose-induced proliferation,oxidative stress,ECM accumulation,and inflammation in mesangial cells

Aberrant regulation in mesangial cell proliferation, extracellular matrix (ECM) accumulation, oxidative stress, and inflammation under hyperglycemic condition contributes significantly to the occurrence and development of diabetic nephropathy (DN). However, the mechanisms underlying the hyperglycemia-induced dysregulations have not been clearly elucidated. Here, we reported that high mobility group box 1 (HMGB1) was highly elevated in high glucose (HG)-treated mesangial cells, and induced the phosphorylation, nuclear translocation, and DNA binding activity of NF-κB via toll-like receptor 4 (TLR4). Function assays showed that inhibition of HMGB1 mitigated HG-induced proliferation, oxidative stress, ECM accumulation, and inflammation in mesangial cells via TLR4/NF-κB pathway. Increasing evidence has shown that circRNA, a large class of noncoding RNAs, functions by binding with miRNAs and terminating regulation of their target genes. We further investigated whether HMGB1 is involved in circRNA–miRNA–mRNA regulatory network. First, HMGB1 was identified and confirmed to be the target of miR-205, and miR-205 played a protective role against HG-induced cell injure via targeting HMGB1. Then circLRP6 was found to be upregulated in HG-treated mesangial cells, and regulate HG-induced mesangial cell injure via sponging miR-205. Besides, overexpression of miR-205 or knockdown of circLRP6 inhibited the NF-κB signaling pathway. Collectively, these data suggest that circLRP6 regulates HG-induced proliferation, oxidative stress, ECM accumulation, and inflammation in mesangial cells via sponging miR-205, upregulating HMGB1 and activating TLR4/NF-κB pathway. These findings provide a better understanding for the pathogenesis of DN.     

Inhibitory effects of dynorphin 3-14 on the lipopolysaccharide-induced toll-like receptor 4 signalling pathway

Dynorphin 1-17 (DYN 1-17) is biotransformed rapidly to a range of fragments in rodent inflamed tissue with dynorphin 3-14 (DYN 3-14) being the most stable and prevalent. DYN 1-17 has been shown previously to be involved in the regulation of inflammatory response following tissue injury, in which the biotransformation fragments of DYN 1-17 may possess similar features. This study investigated the effects of DYN 3-14 on lipopolysaccharide (LPS)-induced nuclear factor-kappaB/p65 (NF-κB/p65) nuclear translocation and the release of pro-inflammatory cytokines interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in differentiated THP-1 cells. Treatment with DYN 3-14 (10 nM) resulted in 35% inhibition of the LPS-induced nuclear translocation of NF-κB/p65. Furthermore, DYN 3-14 modulated both IL-1β and TNF-α release; inhibiting IL-1β and paradoxically augmenting TNF-α release in a concentration-independent manner. A number of opioids have been implicated in the modulation of the toll-like receptor 4 (TLR4), highlighting the complexity of their immunomodulatory effects. To determine whether DYN 3-14 modulates TLR4, HEK-Blue™⁻hTLR4 cells were stimulated with LPS in the presence of DYN 3-14. DYN 3-14 (10 μM) inhibited TLR4 activation in a concentration-dependent fashion by suppressing the LPS signals around 300-fold lower than LPS-RS, a potent TLR4 antagonist. These findings indicate that DYN 3-14 is a potential TLR4 antagonist that alters cellular signaling in response to LPS and cytokine release, implicating a role for biotransformed endogenous opioid peptides in immunomodulation.     

Cloacal temperature responses of broiler chickens administered with betaine and ascorbic acid during the hot-dry season

The experiment was performed to evaluate cloacal temperature (CT) responses in broiler chickens, administered with betaine and ascorbic acid (AA) during the hot–dry season. Broilers were divided into four groups: Group I (control) was given sterile water; Group II, betaine at 250 mg/kg; Group III, AA at 50 mg/kg and Group IV, betaine (250 mg/kg) + AA (50 mg/kg). The different solutions were given orally for 42 days. Dry-bulb temperature (DBT), relative humidity (RH) and temperature-humidity index (THI) in the pen, and CT of each broiler chicken were measured bihourly (06:00–18:00 h) on days 28, 35 and 42. DBT, RH and THI values were outside the thermo-neutral zone for broiler chickens. Results showed that AA lowered (p < 0.001) CT, while betaine + AA increased (p < 0.001) CT, compared with controls. In conclusion, betaine + AA or AA alone modulated CT responses of broiler chickens subjected to the thermal stress in the hot–dry season.     

Effects of antioxidants and nitric oxide on TNF-alpha-induced adhesion molecule expression and NF-kappaB activation in human dermal microvascular endothelial cells

Cell adhesion molecules expressed on endothelial cells in inflamed skin appear to be controlled by the actions of cytokines and reactive oxygen species. However, molecular mechanisms of the expression of adhesion molecules during skin inflammation are currently not well understood. To evaluate the role of antioxidants and nitric oxide in modulating inflammatory processes in the skin, we examined the effects of pyrrolidine dithiocarbamate (PDTC, 0.1 mM) and spermine NONOate (Sper-NO, 1 mM) on adhesion molecule expression and nuclear factor kappa B (NF-kappaB) activation induced by TNF-alpha (10 ng/ml) in cultured human dermal microvascular endothelial cells (HDMEC). Treatment of cells with TNF-alpha for 4 h significantly induced the surface expression of E-selectin and intercellular adhesion molecule-1 (ICAM-1). Treatment with TNF-alpha for 8 h significantly induced the surface expression of E-selectin, ICAM-1 and vascular cell adhesion molecule-1 (VCAM-1). The up-regulation of these adhesion molecules was suppressed significantly by pretreatment with PDTC or Sper-NO for 1 h. The mRNA expression of E-selectin, ICAM-1 and VCAM-1, and activation of NF-kappaB induced by TNF-alpha for 2 h were significantly decreased by the above two pretreatments. N-acetylcysteine (10 mM) and S-nitroso-N-acetylpenicillamine (1 mM) had no significant inhibitory effects on the cell surface and mRNA expression of these adhesion molecules stimulated by TNF-alpha. These findings indicate that both cell surface and mRNA expression of adhesion molecules in HDMEC induced by TNF-alpha are inhibited significantly by pretreatment with PDTC or Sper-NO, possibly in part through blocking the activation of NF-kappaB. These results suggest a potential therapeutic approach using antioxidant agents or nitric oxide pathway modulators in the treatment of inflammatory skin diseases.     

Effects of heme oxygenase-1 on induction and development of chemically induced squamous cell carcinoma in mice

Heme oxygenase-1 (HO-1) is an antioxidative and cytoprotective enzyme, which may protect neoplastic cells against anticancer therapies, thereby promoting the progression of growing tumors. Our aim was to investigate the role of HO-1 in cancer induction. Experiments were performed in HO-1^+/+, HO-1^+/−, and HO-1^−/− mice subjected to chemical induction of squamous cell carcinoma with 7,12-dimethylbenz[a]anthracene and phorbol 12-myristate 13-acetate. Measurements of cytoprotective genes in the livers evidenced systemic oxidative stress in the mice of all the HO-1 genotypes. Carcinogen-induced lesions appeared earlier in HO-1^−/− and HO-1^+/− than in wild-type animals. They also contained much higher concentrations of vascular endothelial growth factor and keratinocyte chemoattractant, but lower levels of tumor necrosis factor-α and interleukin-12. Furthermore, tumors grew much larger in HO-1 knockouts than in the other groups, which was accompanied by an increased rate of animal mortality. However, pathomorphological analysis indicated that HO-1^−/− lesions were mainly large but benign papillomas. In contrast, in mice expressing HO-1, most lesions displayed dysplastic features and developed to invasive carcinoma. Thus, HO-1 may protect healthy tissues against carcinogen-induced injury, but in already growing tumors it seems to favor their progression toward more malignant forms.     

Effects of zinc supplementation on inflammatory biomarkers and oxidative stress in adults: A systematic review and meta-analysis of randomized controlled trials

Background & ObjectiveCurrent evidence is debatable regarding the feasible effects of zinc supplementation on the inflammation and oxidative stress status of adults. This systematic review and meta-analysis aimed to clarify this inconclusiveness.Materials and MethodsLiterature search was conducted via online databases such as PubMed, Scopus, ISI Web of Science, Cochrane Library, and Google Scholar until June 2020. The overall effect was presented as the weighted mean difference (WMD) at 95 % confidence interval (CI) in a random-effects meta-analysis model. Publication bias was also assessed using Egger’s and Begg’s statistics.ResultsIn total, 25 clinical trials (n = 1428) were reviewed, which indicated that zinc supplementation significantly affects the concentration of C- reactive protein (WMD: -0.03 mg/l; 95 % CI: -0.06, 0.0; P = 0.029), interlukin-6 (WMD: -3.81 pg/mL; 95 % CI: -6.87, -0.76; P = 0.014), malondialdehyde (WMD: -0.78 μmol/l; 95 % CI: -1.14, -0.42; P < 0.001), and total antioxidant capacity (WMD: 95.96 mmol/l; 95 % CI: 22.47, 169.44; P = 0.010). In addition, a significant between-study heterogeneity and a non-significant increment was reported in nitric oxide (WMD: 1.47 μmol/l; 95 % CI: -2.45, 5.40; P = 0.461) and glutathione (WMD: 34.84 μmol/l; 95 % CI: -5.12, 74.80; P = 0.087).ConclusionAccording to the results, zinc supplementation may have beneficial anti-inflammatory and anti-oxidative effects in adults.     

ST2 suppresses IL-6 production via the inhibition of IkappaB degradation induced by the LPS signal in THP-1 cells

LPS induces the production of inflammatory cytokines via the stimulation of Toll-like receptors. In this study, we demonstrated that a soluble secreted form of the ST2 gene product (ST2), a member of the interleukin-1 receptor family, suppressed the production of IL-6 in an LPS-stimulated human monocytic leukemia cell line, THP-1. Immunofluorescence confocal microscopy revealed the binding of ST2 to the surface of the THP-1 cells, in which ST2 led to decreased binding of nuclear factor-kappaB to the IL-6 promoter. Furthermore, the degradation of IkappaB in the cytoplasm after LPS stimulation was reduced by pretreatment with ST2. These results demonstrated that ST2 negatively regulates LPS-induced IL-6 production via the inhibition of IkappaB degradation in THP-1 cells.     

Effect of hypoxia/reoxygenation on the biological effect of IGF system and the inflammatory mediators in cultured synoviocytes

Hypoxia/reoxygenation (H/R) plays an important role in the pathogenesis of osteoarthritis. Fibroblast-like synoviocytes (FLS), which are highly sensitive to H/R, are thought to be associated with cartilage degradation during osteoarthritis development. In this study, we investigated the biological effects of insulin-like growth factor (IGF) system and the expression of inflammatory mediators in FLS. We also pretreated FLS with tumor necrosis factor-α (TNF-α) before H/R in order to observe the response of FLS with the background of inflammatory cytokines. H/R increased the levels of TNF-α-induced C-C chemokine ligand 5 (CCL5), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in cell-free culture supernatants; H/R also increased the expression of TNF-α-induced insulin-like growth factor binding protein 3 (IGFBP-3), downregulated the expression of insulin-like growth factor 1 (IGF-1), promoted the loss of mitochondrial membrane potential (MMP), the openness of mitochondrial permeability transition pore (MPTP), the release of intracellular reactive oxygen species (ROS), and mitochondrial matrix swelling, outer membrane rupture and decrease in cristae. Furthermore, H/R induced the expression of catabolic factors and activated the NF-κB signaling pathway in FLS. We therefore concluded that H/R may play a role in inducing inflammation and increase the TNF-α-induced inflammatory effect in FLS, contributing to osteoarthritis pathogenesis.     

Effects of total glucosides of paeony on immune regulatory toll-like receptors TLR2 and 4 in the kidney from diabetic rats

TLRs are a family of receptors that play a critical role in the pathogenesis of diabetic nephropathy. TGP have been shown to have anti-inflammatory and immuno-regulatory activities. However, the relation between TGP and TLRs on diabetic nephropathy remains unknown. In this study, we examined effects of TGP on immune regulatory TLR2 and 4 in the kidney from streptozotocin-induced diabetic rats. TGP decreased the levels of 24 h urinary albumin excretion rate significantly in diabetic rats. Western blot analysis showed that TGP significantly inhibited the expression of TLR2 and 4, MyD88, p-IRAK1, NF-κB p65, p-IRF3, TNF-α and IL-1β. Quantitative real-time PCR analysis showed that the significantly increased levels of TLR2 and 4, and MyD88mRNA in the kidneys of diabetic rats were significantly suppressed by TGP treatment. Macrophages infiltration were also markedly increased in the kidneys of the diabetic rats, but were significantly inhibited by TGP in a dose-dependent manner. These results suggest that TGP has protective effects on several pharmacological targets in the progress of diabetic nephropathy by selectively blocking TLRs activation in vivo.