Riboflavin ameliorates mitochondrial dysfunction via the AMPK/PGC1α/HO­1 signaling pathway and attenuates carbon tetrachloride­induced liver fibrosis in rats.

Hepatic fibrosis is a global health problem, with increasing evidence demonstrating that oxidative stress serves a pivotal role in fibrogenesis. Riboflavin is a vital nutrient in the human and animal diet, which enhances the activity of antioxidant enzymes and ameliorates oxidative stress. The present study evaluated the effect of riboflavin on liver fibrosis and the mechanisms underlying this process. Rats were subcutaneously injected with carbon tetrachloride (CCl4) dissolved in sterile olive oil twice per week to induce hepatic fibrosis. The effect of riboflavin on CCl4-induced liver fibrosis was then assessed. Blood samples and liver tissues were collected and analyzed. The liver tissue morphological changes, immunohistochemical analysis, levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in the mitochondria, and the protein expression levels of α-smooth muscle actin (α-SMA), transforming growth factor-ß1 (TGF-ß1), extracellular signal-regulated kinase (ERK), p38, c-Jun N-terminal kinase (JNK), AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and heme oxygenase 1 (HO-1) in the liver were also analyzed. The results demonstrated that riboflavin treatment significantly decreased the levels of alanine transaminase and aspartate transaminase in the serum, increased SOD activity and modulated the MDA level in the mitochondria. Furthermore, riboflavin significantly inhibited the CCl4-induced, upregulated protein expression levels of phosphorylated (p)-ERK, p-p38, p-JNK, TGF-ß1 and α-SMA. Moreover, riboflavin significantly increased the expression of p-AMPK, PGC-1α and HO-1 in the liver tissue. These results suggested that riboflavin delays CCl4-induced hepatic fibrosis by enhancing the mitochondrial function via the AMPK/PGC-1α/HO-1 and mitogen-activated protein kinase signaling pathways.

Knockout of PKC θ gene attenuates oleic acid-induced acute lung injury via reduction of inflammation and oxidative stress.

OBJECTIVES: Acute respiratory distress syndrome resulting from acute lung injury has become a momentous clinical concern because of high morbidity and mortality in discharged patients with pulmonary and nonpulmonary diseases. This study aimed to explore the effect of protein kinase C (PKC) θ gene knockout on acute lung injury. MATERIALS AND METHODS: Wt and PKC θ gene knockout mice were intravenously injected with oleic acid to induce acute lung injury. Pulmonary capillary permeability was assessed via measuring lung wet/dry weight ratio and level of protein in bronchoalveolar lavage fluid (BALF). Histological changes were used to examine acute lung injury. Malondialdehyde (MDA) level, superoxide dismutase (SOD) activity in serum, together with inflammatory cytokines including interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α), were determined. Furthermore, the expressions of heme oxygenase (HO)-1, nuclear factor kappa B (NF κB), and inhibitor of NF-κB alpha (IκB α) were detected in the lungs. RESULTS: PKC θ gene knockout decreased lung wet/dry weight ratio, reduced levels of MDA, IL-6, and TNF-α in serum together with level of protein in BALF. Furthermore, PKC θ gene knockout increased the activities of SOD. Knockout of PKC θ was also observed to increase expression of HO-1 and reduce levels of p-NF κB and p-IKB α in the lungs. CONCLUSION: These results suggest that PKC θ gene knockout attenuates oleic acid-induced acute lung injury via improving oxidative stress and inflammation.

Recombinant fusion protein by lysozyme and antibacterial peptide enhances ischemic wound healing via angiogenesis and reduction of inflammation in diabetic db/db mice.

BACKGROUND & AIMS: Lysozyme and antibacterial peptides have been reported to broad-spectrum antibacterial activity and can further improve wound healing. The aim of this study was to assess the effectiveness of a recombinant fusion protein created by combining lysozyme and an antibacterial peptide in forming new vessels and wound healing in an ischemic hind limb. METHODS: An ischemic hind limb model was established by isolation and ligation of the femoral artery in diabetic db/db mice. Cutaneous wounds were created with or without ischemia. Adductor muscles and wounds were treated with or without the fusion protein. RESULTS: The fusion protein accelerated ischemic diabetic wound healing and attenuated impairment of ischemic adductor muscle . Further, the fusion protein elevated expression of platelet derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) protein and mRNA in ischemic adductor muscle, reduced levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in serum and expression of phosphorylated nuclear factor κB (p-NF-κB) and p-IKB α in ischemic adductor. The fusion protein also enhanced levels of phosphorylated VEGF and PDGF receptors in the ischemic adductor muscles from diabetic db/db mice. CONCLUSION: The data showed that the beneficial effects of the fusion protein on ischemic wound healing may be associated with angiogenesis and reduction of inflammatory response in the ischemic adductor muscles of diabetic db/db mice.

Cardiac dysfunction is attenuated by ginkgolide B via reducing oxidative stress and fibrosis in diabetic rats.

OBJECTIVES: Diabetic cardiomyopathy is a leading factor of high morbidity and mortality in diabetic patients. Our previous results revealed that ginkgolide B alleviates endothelial dysfunction in diabetic rats. This study aimed to investigate the effect of ginkgolide B on cardiac dysfunction and its mechanism in diabetic rats. MATERIALS AND METHODS: Diabetes was induced in rats through the intraperitoneal injection of streptozotocin (STZ). Hemodynamics was monitored to assess cardiac function. Oxidative stress was examined by detecting levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in serum, and expression of sirtuin (SIRT)1, heme oxygenase (HO)-1, and phosphorylated AMPK in the heart. Masson's trichrome staining and expression of transforming growth factor (TGF)-ß1, smooth muscle actin (α-SMA), and phosphorylated (p-) Smad2 and Smad3 were used to evaluate cardiac fibrosis. Inflammatory cytokine in serum and levels of p-PI3K, p-Akt, p-p38, and p-JNK in the heart were determined. RESULTS: Ginkgolide B significantly improved hemodynamics in diabetic rats. Compared with diabetic rats, treatment with ginkgolide B significantly decreased levels of inflammatory cytokines, improved oxidative stress via reducing MDA concentration, and elevating SOD activity in serum and increasing expression of SIRT1, HO-1, and p-AMPK. Further, ginkgolide B alleviated cardiac fibrosis by decreasing expression of TGF-ß1, α-SMA, and p-Smad2 and p-Smad3. Meanwhile, ginkgolide B reduced Levels of p-P38, and p-JNK, and increased levels of p-PI3K and p-Akt. CONCLUSION: The results suggested that ginkgolide B alleviated cardiac dysfunction by reducing oxidative stress and cardiac fibrosis.

The extract from Agkistrodon halys venom protects against lipopolysaccharide (LPS)-induced myocardial injury.

BACKGROUND: Snake venoms contain various bioactive constituents which possess potential therapeutic effects. The aim of this work was to investigate the effect of the extract from Agkistrodon halys venom on lipopolysaccharide (LPS)-induced myocardial injury. METHODS: Thirty male Sprague-Dawley rats were randomly assigned to three groups (10 rats per group): control group, LPS group and LPS + extract group. Rats in control and the LPS groups were intravenously injected with sterile saline solution, and rats in the LPS + extract group with the extract. After 2 h, rats of the control group were intraperitoneally injected sterile saline solution, and rats in the LPS and the LPS + extract groups were treated with LPS (20 mg per kg body weight). Levels of creatine kinase (CK) and lactate dehydrogenase (LDH) in serum were determined. Anti-inflammation of the extract was analyzed via determination of TNF-α and IL-6 in serum, and expression of TNF-α, IL-6, COX-2 and p-ERK protein in hearts. Heme oxygenase-1 (HO-1) and p-NF-κB protein expression in hearts, superoxide dismutase (SOD) activity and malondialdehyde (MDA) level in serum were used to evaluate the anti-oxidative properties of the extract. RESULTS: Extract pretreatment significantly decreased the level of serum CK and LDH, reduced the generation of inflammatory cytokines such as TNF-α and IL-6, and also reduced serum level of MDA in the LPS + extract group compared with the LPS group. In addition, the extract increased SOD activity in serum, HO-1 protein expression in hearts, and decreased TNF-α, IL-6, COX-2, p-NF-κB and p-ERK1/2 protein expression. CONCLUSION: Our results suggested that beneficial effect of this extract might be associated with an improved anti-oxidation and anti-inflammatory effect via downregulation of NF-κB/COX-2 signaling by activating HO-1/CO in hearts.

Hydrogen sulfide improves vessel formation of the ischemic adductor muscle and wound healing in diabetic db/db mice.

OBJECTIVES: It has been demonstrated that hydrogen sulfide plays a vital role in physiological and pathological processes such as regulating inflammation, oxidative stress, and vessel relaxation. The aim of the study was to explore the effect of hydrogen sulfide on angiogenesis in the ischemic adductor muscles of type 2 diabetic db/db mice and ischemic diabetic wound healing. MATERIALS AND METHODS: The femoral arteries of diabetic db/db mice were isolated and ligated for preparation of ischemic hind limb model. Round incision was made on ischemic and non-ischemic limbs. The wounds were treated with sodium bisulfide (hydrogen sulfide donor). Real-time PCR and Western blotting were used to measure transcription of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), platelet derived growth factor (PDGF), hypoxia inducible factor-1α (HIF-1α) and endothelial nitric oxide synthase (eNOS) and protein expression of VEGF, VEGF receptor (VEGFR) and PDGF, PDGF receptor (PDGFR), respectively. Angiogenesis and morphological changes in adductor muscles were observed. RESULTS: Hydrogen sulfide significantly increased transcription of VEGF, EGF, PDGF, HIF-1α, eNOS and protein expression of VEGF, PDGF, and phosphorylated VEGFR and PDGFR. Treatment with hydrogen sulfide significantly improved ischemic wound healing and formation of granulation tissue, and increased the number of small vessels in the ischemic adductor muscles. CONCLUSION: Our data suggested that hydrogen sulfide attenuated injury of ischemic adductor muscle, and promoted the ischemic diabetic wound healing via modulating angiogenesis in type 2 diabetic db/db mice.

Lycopene attenuates LPS-induced liver injury by inactivation of NF-κB/COX-2 signaling.

AIM: This study aimed to investigate the effect of lycopene on LPS-induced liver injury in mice and its mechanisms. METHODS: Male C57bl/6 mice were randomly assigned to three groups: sham control group (S-C), LPS control group (L-C), lycopene treatment group (L-T). The mice from the L-T were treated with lycopene for 2 weeks, and the remaining mice with solvent. Afterwards, the mice from the L-C and the L-T received an intraperitoneal injection of LPS (20 mg/kg, dissolved in sterile saline), and the S-C mice were injected with sterile saline. Serum levels of alanine transaminase (ALT) and aspartate aminotransferase (AST) were determined for analysis of liver function. Levels of inflammatory cytokines including tumor necrosis factor (TNF)-α and interleukin (IL)-6, malondialdehyde (MDA) content, and the activity of superoxide dismutase (SOD), were detected in serum. Liver tissues were operated for morphologic analysis and determination of protein by western blot. RESULTS: Pretreatment with lycopene significantly decreased levels of ALT, AST, and TNF-α and IL-6, reduced MDA content, and increased activity of SOD in serum compared with the L-C mice. Lycopene increased expression of nuclear factor-erythroid 2 related factor 2 (Nrf2), and reduced expression of cyclooxygenase (COX)-2, and phosphorylation of nuclear factor-kappa B (NF-κB) and extracellular regulated protein kinases 1/2 (ERK1/2). CONCLUSION: The results showed that lycopene attenuates LPS-induced liver injury by reducing NF-κB/COX-2 signaling by upregulation of Nrf2/HO-1 activation.

Heme Oxygenase-1 Promotes Delayed Wound Healing in Diabetic Rats.

Diabetic ulcers are one of the most serious and costly chronic complications for diabetic patients. Hyperglycemia-induced oxidative stress may play an important role in diabetes and its complications. The aim of the study was to explore the effect of heme oxygenase-1 on wound closure in diabetic rats. Diabetic wound model was prepared by making an incision with full thickness in STZ-induced diabetic rats. Wounds from diabetic rats were treated with 10% hemin ointment for 21 days. Increase of HO-1 protein expression enhanced anti-inflammation and antioxidant in diabetic rats. Furthermore, HO-1 increased the levels of VEGF and ICAM-1 and expressions of CBS and CSE protein. In summary, HO-1 promoted the wound closure by augmenting anti-inflammation, antioxidant, and angiogenesis in diabetic rats.

[Study of PL Spectra of PbSe Quantum Dots for IC Chip Temperature Dependence].

Colloidal PbSe QDs were prepared with the particle size of 3. 6, 5. 1 and 6. 0 nm, and the temperature-dependent optical properties of colloidal PbSe QDs were investigated. At the room temperature, the experiment showed that there is red shift with increasing temperature; photoluminescence spectra of large size colloidal PbSe QDs is blue shifted with increasing temperature. Proposed a temperature detection method of integrated circuit was proposed based on photoluminescence spectra of colloidal PbSe QDs. The method for temperature detection includes colloidal PbSe quantum dots deposited on the surface of the printed circuit board, colloidal PbSe quantum dots of the surface are excited by the laser and infrared spectrometer receives photoluminescence spectra. Image acquisition system used for micron scale areas of temperature detection collects a tiny and specific areas imaging in the surface of chip. Experiments showed that the measurement accuracy is ±3 °C and the relative error is less than 5%.

Ginkgolide B increases hydrogen sulfide and protects against endothelial dysfunction in diabetic rats.

AIM: To evaluate the effect of ginkgolide B treatment on vascular endothelial function in diabetic rats. METHODS: The study included four groups with 15 male Sprague-Dawley rats: control group; control group treated with ginkgolide B; diabetic group; and diabetic treated with ginkgolide B. The activity of superoxide dismutase (SOD), malondialdehyde content, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, and glutathione peroxidase 1 (GPX1) protein expression were determined in aortic tissues. Vasoconstriction to phenylephrine (PHE) and vasorelaxation to acetylcholine (Ach) and sodium nitroprusside (SNP) were assessed in aortic rings. Nitric oxide (NO) and hydrogen sulfide (H2S) were measured, as well as cystathionine γ lyase (CSE) and cystathionine ß synthetase (CBS) protein expression, and endothelial nitric oxide synthase (eNOS) activity. RESULTS: Diabetes significantly impaired PHE-induced vasoconstriction and Ach-induced vasorelaxation (P<0.001), reduced NO bioavailability and H2S production (P<0.001), SOD activity, and GPX1 protein expression (P<0.001), and increased malondialdehyde content and NADPH oxidase subunits, and CSE and CBS protein expression (P<0.001). Ginkgolide B treatment improved PHE vasoconstriction and Ach vasorelaxation (P<0.001), restored SOD (P=0.005) and eNOS (P<0.001) activities, H2S production (P=0.044) and decreased malondialdehyde content (P=0.014). Vasorelaxation to SNP was not significantly different in control and diabetic rats with or without ginkgolide B treatment. Besides, ginkgolide B increased GPX1 protein expression and reduced NADPH oxidase subunits, CBS and CSE protein expression. CONCLUSION: Ginkgolide B alleviates endothelial dysfunction by reducing oxidative stress and elevating NO bioavailability and H2S production in diabetic rats.

Taurine attenuates oxidative stress and alleviates cardiac failure in type I diabetic rats.

AIM: To investigate cardioprotective effect of taurine in diabetic rats. METHODS: Male Sprague-Dawley rats were assigned randomly into four groups of 15 rats: control group, control+taurine group, streptozotocin (STZ) group, and STZ + taurine group. Rats in STZ and STZ+ taurine groups were treated by a single injection of STZ (70 mg kg-1, intraperitoneally) dissolved in 0.01 M citrate buffer (pH 4.5) for induction of diabetes, and rats in control and control+taurine groups were treated with the same volume citrate buffer. Taurine was orally administered to rats in control+taurine and STZ + taurine groups daily for 8 weeks. Rats were examined for diabetic cardiomyopathy by left ventricular (LV) hemodynamic analysis. Myocardial oxidative stress was assessed by measuring the activity of superoxide dismutase (SOD) and the level of malondialdehyde (MDA). Myocardial protein kinase B (Akt/PKB) phosphorylation and heme oxygenase-1 (HO-1) protein levels were measured by Western blot in all rats at the end of the study. RESULTS: In untreated diabetic rats, LV systolic pressure, rate of pressure rise, and rate of pressure fall were decreased, while LV end-diastolic pressure was increased, indicating reduced LV contractility and slowing of LV relaxation. The levels of Akt/PKB phosphorylation and SOD activity were decreased and HO-1 protein expression and MDA content increased. Taurine treatment significantly improved LV systolic and diastolic function, and there were persistent increases in activities of Akt/PKB and SOD, and the level of HO-1 protein. CONCLUSION: Taurine treatment ameliorates myocardial function and heart oxidant status, while increasing myocardial Akt/PKB phosphorylation, and HO-1 levels have beneficial effects on diabetic cardiomyopathy.

Protective Effects of Luteolin on Diabetic Nephropathy in STZ-Induced Diabetic Rats.

Diabetic nephropathy is a long-term complication of diabetic mellitus. Many experimental evidences suggest that persistent hyperglycaemia generates intracellular reactive oxygen species (ROS) and upregulates transforming growth factor-b1 and extracellular matrix expression in mesangial and tubular epithelial cells, which is involved of free radicals in the pathogenesis of diabetes and more importantly in the development of diabetic complications. Antioxidants effectively inhibit high-glucose- and H2O2-induced transforming growth factor-b1 and fibronectin upregulation, thus providing evidence that ROS play an important role in high glucose-induced renal injury. The flavonoid luteolin has been shown to possess direct antioxidant activity, therefore we hypothesize that it may be useful in treatment of many chronic disease associated with oxidative stress, such as diabetic nephropathy via its antioxidant properties. Our results suggested that protection against development of diabetic nephropathy by luteolin treatment involved changes in superoxide dismutase (SOD) activity, the malondialdehyde (MDA) content and expression of Heme Oxygenase-1 (HO-1) protein.

[Protective effects of luteolin preconditioning on rat liver under ischemia/reperfusion].

The aim of the study is to explore the effects of luteolin preconditioning on hepatic ischemia/reperfusion injury in rats and its mechanism, and investigate the effects of the change of heme oxygenase-1 (HO-1) activity on hepatic ischemia/reperfusion injury. Sprague-Dawley rats were divided into 5 groups randomly: control, model, luteolin, luteolin + zinc protoporphyrin (ZnPP, an inhibitor of HO-1) and hemin groups (n = 8 for each group). The rats in control, model and hemin groups received a standard chow daily. The rats in luteolin and luteolin + ZnPP groups received a chow supplemented with luteolin (200 mg/kg) daily. After 4 weeks, ZnPP (25 µmol/kg) and hemin (20 µmol/kg) were injected hypodermically 6 h before ischemia/reperfusion in luteolin + ZnPP and hemin groups, respectively. Portal vein and hepatic artery supplying the middle and left hepatic lobe were clamped with an atraumatic vascular clip for induction of partial hepatic ischemia in all rats except control group. After the 60 min of hepatic ischemia, a 60-minute reperfusion period was initiated by removal of the arterial clip. The levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were detected in serum, and the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) in serum and liver were measured with assay kit. The expression of HO-1 protein and activity of HO-1 were examined in liver. The results showed that the luteolin and hemin pretreatment led to significant decreased levels of AST and ALT in serum, increased activity of SOD and decreased content of MDA in serum and liver compared with model group (P < 0.01). In addition, the expression of HO-1 protein and activity of HO-1 were elevated in luteolin and hemin groups (P < 0.01). ZnPP markedly increased the levels of AST and ALT in serum, and decreased the activities of SOD and HO-1, elevated MDA content in liver when compared with those in luteolin group (P < 0.01). Cytoplasmic vacuolation and swelling of hepatocytes were revealed in the model group after ischemia/reperfusion. Treatments with luteolin and hemin markedly relieved the liver structural changes. These results suggest that HO-1 protects rat liver from ischemia/reperfusion injury, and luteolin reduces the content of MDA and increases the activity of SOD and the expression of HO-1, which indicate that luteolin can elevate the antioxidation in rat liver, and thus protects rat liver from ischemia/reperfusion injury.

[Apoptosis of K562 cells induced by extract of Agkistrodon Halys' venom].

The study was purposed to investigate the effect of extract of Agkistrodon Halys venom on proliferation and apoptosis of K562 cells. The inhibition of K562 cell proliferation was measured by MTT assay; The morphologic changes of K562 cells was observed by microscopy; the apoptosis of K562 cells was measured by flow cytometry; the activity of extracellular signal-regulated kinase (ERK) in K562 cells was detected by Western blot. The results showed that when K562 cells were treated with 0, 1, 10, 20 microg/ml of the extraction for 48 hours, the apoptosis rates were 2.1%, 21.3%, 49.7%, 70.1%, respectively. The proliferation of K562 cells was obviously inhibited in dose-dependent manner. Typical morphologic changes significantly appeared in the extract-treated K562 cells. The extract obviously inhibited the activity of ERK in K562 cells. It is concluded that the extract of Agkistrodon Halys' venom can inhibit the proliferation of K562 cells and induce apoptosis of K562 cells.