Raspberry Ketone Reduced Lipid Accumulation in 3T3-L1 Cells and Ovariectomy-Induced Obesity in Wistar Rats by Regulating Autophagy Mechanisms.

This study aimed to determine the antiobesity effects of raspberry ketone (RK), one of the major aromatic compounds contained in raspberry, and its underlying mechanisms. During adipogenesis of 3T3-L1 cells, RK (300 µM) significantly reduced lipid accumulation and downregulated the expression of CCAAT/enhancer-binding protein α (C/EBPα), peroxisome proliferation-activated receptor γ (PPARγ), fatty acid-binding protein 4 (FABP4), and fatty acid synthase (FAS). RK also reduced the expression of light chain 3B (LC3B), autophagy-related protein 12 (Atg12), sirtuin 1 (SIRT1), and phosphorylated-tuberous sclerosis complex 2 (TSC2), whereas it increased the level of p62 and phosphorylated-mammalian target of rapamycin (mTOR). Daily administration of RK decreased the body weight (ovariectomy [Ovx] + RK, 352.6 ± 5 vs Ovx, 386 ± 5.8 g; P < 0.05), fat mass (Ovx + RK, 3.2 ± 0.05 vs Ovx, 5.0 ± 0.4 g; P < 0.05), and fat cell size (Ovx + RK, 6.4 ± 0.6 vs Ovx, 11.1 ± 0.7 × 103 µm2; P < 0.05) in Ovx-induced obesity in rats. The expression of PPARγ, C/EBPα, FAS, and FABP4 was significantly reduced in the Ovx + RK group compared with that in the Ovx group. Similar patterns were observed in autophagy-related proteins and endoplasmic reticulum stress proteins. These results suggest that RK inhibited lipid accumulation by regulating autophagy in 3T3-L1 cells and Ovx-induced obese rats.

Heme oxygenase-1 mediates anti-adipogenesis effect of raspberry ketone in 3T3-L1 cells.

BACKGROUND: Obesity is caused by excessive accumulation of body fat and is closely related to complex metabolic diseases. Raspberry ketone (RK), a major aromatic compound in red raspberry, was recently reported to possess anti-obesity effects. However, its mechanisms are unclear. AIM: Adipogenesis plays a critical role in obesity and, therefore, this study aimed to investigate the effect and mechanisms of action of RK on adipogenesis in 3T3-L1 preadipocytes. MATERIALS AND METHODS: 3T3-L1 preadipocytes were differentiated in medium containing insulin, dexamethasone, and 1-methyl-3-isobutylxanthine. Adipocyte lipid contents were determined using oil-red O staining while adipogenic transcription factor and lipogenic protein expressions were determined using western blotting. RESULTS: RK (300-400µM) strongly inhibited lipid accumulation during 3T3-L1 preadipocyte differentiation into adipocytes. RK reduced the CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferation-activated receptor-γ (PPAR-γ), fatty acid synthase (FAS), and fatty acid-binding protein 4 (FABP4) expressions and increased heme oxygenase-1 (HO-1), Wnt10b, and ß-catenin expressions in 3T3-L1 adipocytes. Additionally, RK inhibited lipid accumulation, and adipogenic transcription factor and lipogenic protein expressions were all decreased by inhibiting HO-1 or ß-catenin using tin protoporphyrin (SnPP) or ß-catenin short-interfering RNA (siRNA), respectively. Furthermore, Wnt10b and ß-catenin expressions were negatively regulation by SnPP. CONCLUSION: RK may exert anti-adipogenic effects through modulation of the HO-1/Wnt/beta-catenin signaling pathway.

Celastrol prevents circulatory failure via induction of heme oxygenase-1 and heat shock protein 70 in endotoxemic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Celastrol, a quinone methide extracted from the root of Tripterygium wilfordii Hook, possesses anti-oxidant and anti-inflammatory effects. Tripterygium wilfordii Hook is officially listed in the Chinese Pharmacopoeia and is used traditionally against rheumatoid arthritis, ankylosing spondylitis, and cancer. Furthermore, the circulatory protective effect of celastrol on an in vivo animal model of sepsis was investigated. AIM OF THE STUDY: Sepsis is a systemic inflammatory disorder that increases tissue oxidative stress and leads to multiple organ injury. We evaluated the beneficial effects of celastrol on multiple organ failure induced by lipopolysaccharide (LPS) in rats. MATERIALS AND METHODS: Celastrol (0.5 and 1.0 mg/kg, i.v.) was administered to anaesthetized rats 2 h before and 30 min after LPS challenge (10 mg/kg, i.v.). Eight hours later, cardiac and aortic protein expressions related to inflammatory responses, superoxide anion production, and reduced glutathione (GSH) level were measured. RESULTS: Treatment with celastrol prevented circulatory failure (bradycardia and hypotension) 8h after LPS challenge. The plasma levels of ALT, LDH, TNF-α, and nitric oxide metabolites increased markedly during sepsis, which significantly reduced after celastrol treatments. Celastrol attenuated iNOS, TNF-α, NF-κB phospho-p65 expression, superoxide anion production, and caspase 3 activity in the cardiovascular system, all of which were markedly elevated after LPS challenge. Furthermore, celastrol induced HO-1 and HSP70 expressions increase in nuclear levels of Nrf2 and HSF-1, respectively, and increase cardiac GSH level 8h after LPS challenge. CONCLUSION: Anti-inflammatory and anti-oxidant effects of celastrol contribute to prevent circulatory failure in sepsis. Induction of HO-1 and HSP70 by celastrol participates in these beneficial effects.

Reciprocal effects of α-lipoic acid on adenosine monophosphate-activated protein kinase activity in obesity induced by ovariectomy in rats.

OBJECTIVE: Adenosine monophosphate (AMP)-activated protein kinase (AMPK) plays an important role in regulating whole-body energy homeostasis. The aim of this study was to investigate dietary α-lipoic acid (α-LA) supplementation on the activation of AMPK in both central and peripheral tissues in obese rats induced by ovariectomy. METHODS: Ovariectomized (Ovx) rats were treated with α-LA (200 mg/kg) 3 to 10 weeks after surgery. Body weight, food intake, fat mass, phosphorylated AMPKα (pAMPKα), and phosphorylated acetyl-CoA carboxylase (ACC) protein expression in both the hypothalamus and white adipose tissue (WAT) as well as plasma leptin and adiponectin levels were measured in rats after either Ovx or sham operations. RESULTS: Compared with control rats, ovariectomy led to increased body weight, food intake, and WAT mass 2 to 10 weeks after surgery. Furthermore, plasma leptin and adiponectin levels as well as hypothalamic pAMPKα expression were significantly increased after ovariectomy, accompanied by a reduction in pAMPKα expression in WAT after ovariectomy. However, after treatment with α-LA, the elevation of leptin and adiponectin levels and the activation of hypothalamic AMPKα and ACC, as induced by ovariectomy, were significantly suppressed. Meanwhile, decreased fat mass and increased pAMPKα and phosphorylated ACC expression in the WAT were observed in Ovx rats treated with α-LA. CONCLUSIONS: α-LA significantly decreased appetite and fat accumulation, possibly through the regulation of central and peripheral AMPK activities in rats. Therefore, this study provides a rationale for the therapeutic use of α-LA for obesity in postmenopausal women.

Wogonin suppresses arrhythmias, inflammatory responses, and apoptosis induced by myocardial ischemia/reperfusion in rats.

Wogonin is a flavonoid isolated from Scutellaria baicalensis Georgi, a traditional Chinese medicine, and it possesses antioxidant and anti-inflammatory effects. The aim of this study is to investigate the in vivo effect of wogonin on myocardial ischemia/reperfusion injury in an open-chest anesthetized rat model, which was induced by 45-minute left coronary artery occlusion and 2-hour reperfusion. Rats were treated with wogonin (5, 10, and 20 mg/kg, intraperitoneal) 40 minutes before ischemia or treatment with 10 mg/kg of wogonin 15 minutes after occlusion. Pretreatment with 10 mg/kg of wogonin significantly delayed the occurrence of ventricular premature contractions and tachycardia, and it suppressed the incidence of ventricular tachycardia and ventricular fibrillation, and mortality elicited by ischemia when compared with that in the control group, accompanied by reducing the arrhythmia scores. After 2-hour reperfusion, pretreatment and posttreatment with wogonin significantly reduced the infarct size and plasma levels of creatine kinase muscle-brain fraction and lactate dehydrogenase. Wogonin also significantly reduced the elevation of plasma tissue necrosis factor-α and superoxide anion production in the myocardium with ischemia/reperfusion. The expression of monocyte chemoattractant protein-1, phosphorylated p38 mitogen-activated protein kinase, p65 and IκBα, and active caspase-3 in ischemic myocardium pronouncedly increased in the control group; these were significantly attenuated by treatment with wogonin. In conclusion, wogonin demonstrated in vivo cardioprotective effects by the attenuation of the severity of ischemia-induced arrhythmias and irreversible ischemia/reperfusion injury, which is associated with its antioxidant capacity and anti-inflammatory effects. The suppression of nuclear factor-κB and p38 mitogen-activated protein kinase activation and the inhibition of monocyte chemoattractant protein-1 expression contribute to the beneficial effects of wogonin.

Baicalein, an active component of Scutellaria baicalensis Georgi, improves cardiac contractile function in endotoxaemic rats via induction of heme oxygenase-1 and suppression of inflammatory responses.

AIM OF THE STUDY: To evaluate the protective effect of baicalein on myocardial dysfunction caused by endotoxaemia in rats and to explore the possible mechanisms. MATERIALS AND METHODS: Baicalein (10mg/kg, intravenous) was administered to conscious Wistar rats 30min after lipopolysaccharide (LPS; 10mg/kg, intravenous) challenge. Six hours after LPS administration, the contractile function of the isolated heart was examined using the Langendorff technique. Cardiac protein expression related to inflammatory responses, superoxide anion production and caspase-3 activity were measured. RESULTS: Post-treatment with baicalein significantly attenuated the LPS-induced hypotension with accompanying tachycardia. The contractile function of isolated heart was significantly preserved 6h after LPS administration, following treatment with baicalein. Furthermore, baicalein induced the expression of heme oxygenase-1 protein and reduced superoxide anion formation in the myocardium of LPS-treated rats. Cardiac levels of inducible nitric oxide synthase, monocyte chemoattractant protein-1, phospho-IκBα and phospho-p65 protein and caspase-3 activity significantly increased 6h after LPS challenge but baicalein significantly attenuated these LPS-induced changes. CONCLUSIONS: Baicalein improves myocardial contractility in LPS-induced sepsis, which may be related to reductions in oxidative stress, myocardial inflammatory responses and apoptosis.

The role of hypothalamic AMP-activated protein kinase in ovariectomy-induced obesity in rats.

OBJECTIVE: Adenosine monophosphate-activated protein kinase (AMPK) acts as a cellular energy sensor, being activated during states of low energy charge. Hypothalamic AMPK is altered by hormonal and metabolic signals and mediates the feeding response. The aims of this study were to examine whether the phosphorylation of AMPKα in the hypothalamus is affected by ovariectomy (Ovx) and thus would be involved in the development of obesity in rats. METHODS: Body weight, food intake, hypothalamic phosphorylated AMPKα (pAMPKα) protein expression, and plasma leptin and adiponectin levels were measured in female rats after either Ovx or sham operations. These patterns were also observed after treatment with 17ß-estradiol, compound C, and leptin in Ovx rats. RESULTS: Compared with control rats, Ovx led to increased body weight and food intake at 2 to 8 weeks after operation. Meanwhile, plasma leptin and adiponectin levels and hypothalamic pAMPKα expression were significantly increased after Ovx. Replacement of estradiol significantly reversed these effects. Treatment with compound C, an AMPKα inhibitor, for 1 week produced a reduction in food intake, body weight, and plasma leptin and adiponectin levels. Meanwhile, these effects were reversed upon withdrawal of compound C. In addition, central injection of leptin also significantly reduced body weight, food intake, plasma leptin and adiponectin levels, and hypothalamic pAMPKα expression relative to those of the Ovx group. CONCLUSIONS: Increased hypothalamic pAMPKα expression may contribute to hyperphagia during the development of Ovx-induced obesity in rats.

Protective effect of baicalein against endotoxic shock in rats in vivo and in vitro.

Dried roots of Scutellaria baicalensis Georgi (Huang qin) are widely used in traditional Chinese medicine. Baicalein is a major bioactive flavonoid component of H. qin that shows a wide range of biological activities, including antioxidant and anti-inflammatory actions. We evaluated therapeutic effects and possible mechanisms of action of baicalein on circulatory failure and vascular dysfunction during sepsis induced by lipopolysaccharide (LPS; 10 mg/kg, i.v.) in anesthetized rats. Treatment of the rats with baicalein (20 mg/kg, i.v.) significantly attenuated the deleterious hemodynamic changes of hypotension and tachycardia caused by LPS and significantly inhibited the elevation of plasma tumor necrosis factor alpha (TNF-alpha). Baicalein also decreased levels of inducible nitric oxide synthase (iNOS) and the overproduction of NO and superoxide anions caused by LPS. It also increased the survival rate of ICR mice (25-30 g) challenged by LPS (60 mg/kg). Moreover, infiltration of neutrophils into the liver and lungs of rats 6h after treatment with LPS was also reduced by baicalein. To investigate the mechanism of action of baicalein on sepsis, RAW 264.7 cells were used as a model. Baicalein inhibited iNOS protein production, and suppressed LPS-induced degradation of IkappaBalpha, the formation of a nuclear factor kappa B (NF-kappaB)-DNA complex and NF-kappaB-dependent reporter gene expression. Thus, the therapeutic effects of baicalein were associated with reductions in TNF-alpha and superoxide anion levels during sepsis. The inhibitory effects of baicalein on iNOS production may be mediated by inhibition of the activation of NF-kappaB. Baicalein may thus prove a potential agent against endotoxemia.

Tetramethylpyrazine induces heme oxygenase-1 expression and attenuates myocardial ischemia/reperfusion injury in rats.

The accumulation of oxygen free radicals and activation of neutrophils are strongly implicated as pathophysiological mechanisms mediating myocardial ischemia/reperfusion injury. Heme oxygenase-1 (HO-1) has been reported to play a protective role in oxidative tissue injuries. In this study, the cardioprotective activity of tetramethylpyrazine (TMP), an active ingredient of Chinese medicinal herb Ligusticum wallichii Franchat, was evaluated in an open-chest anesthetized rat model of myocardial ischemia/reperfusion injury. Pretreatment with TMP (5 and 10 mg/kg, i.v.) before left coronary artery occlusion significantly suppressed the occurrence of ventricular fibrillation. After 45 min of ischemia and 1 h of reperfusion, TMP (5 and 10 mg/kg) caused a significant reduction in infarct size and induced HO-1 expression in ischemic myocardium. The HO inhibitor ZnPP (50 microg/rat) markedly reversed the anti-infarct action of TMP. Superoxide anion production in ischemic myocardium after 10 min reperfusion was inhibited by TMP. Furthermore, TMP (200 and 500 microM) significantly suppressed fMLP (800 nM)-activated human neutrophil migration and respiratory burst. In conclusion, TMP suppresses ischemia-induced ventricular arrhythmias and reduces the infarct size resulting from ischemia/reperfusion injury in vivo. This cardioprotective activity of TMP may be associated with its antioxidant activity via induction of HO-1 and with its capacity for neutrophil inhibition.