Mori Ramulus Suppresses Hydrogen Peroxide-Induced Oxidative Damage in Murine Myoblast C2C12 Cells through Activation of AMPK.

Mori Ramulus, the dried twigs of Morus alba L., has been attracting attention for its potent antioxidant activity, but its role in muscle cells has not yet been elucidated. The purpose of this study was to evaluate the protective effect of aqueous extracts of Mori Ramulus (AEMR) against oxidative stress caused by hydrogen peroxide (H2O2) in C2C12 mouse myoblasts, and in dexamethasone (DEX)-induced muscle atrophied models. Our results showed that AEMR rescued H2O2-induced cell viability loss and the collapse of the mitochondria membrane potential. AEMR was also able to activate AMP-activated protein kinase (AMPK) in H2O2-treated C2C12 cells, whereas compound C, a pharmacological inhibitor of AMPK, blocked the protective effects of AEMR. In addition, H2O2-triggered DNA damage was markedly attenuated in the presence of AEMR, which was associated with the inhibition of reactive oxygen species (ROS) generation. Further studies showed that AEMR inhibited cytochrome c release from mitochondria into the cytoplasm, and Bcl-2 suppression and Bax activation induced by H2O2. Furthermore, AEMR diminished H2O2-induced activation of caspase-3, which was associated with the ability of AEMR to block the degradation of poly (ADP-ribose) polymerase, thereby attenuating H2O2-induced apoptosis. However, compound C greatly abolished the protective effect of AEMR against H2O2-induced C2C12 cell apoptosis, including the restoration of mitochondrial dysfunction. Taken together, these results demonstrate that AEMR could protect C2C12 myoblasts from oxidative damage by maintaining mitochondrial function while eliminating ROS, at least with activation of the AMPK signaling pathway. In addition, oral administration of AEMR alleviated gastrocnemius and soleus muscle loss in DEX-induced muscle atrophied rats. Our findings support that AEMR might be a promising therapeutic candidate for treating oxidative stress-mediated myoblast injury and muscle atrophy.

The preventive effect of Mori Ramulus on oxidative stress-induced cellular damage in skeletal L6 myoblasts through Nrf2-mediated activation of HO-1.

The aim of the present study is to investigate the preventive effect of water extract of Mori Ramulus (MRWE) on oxidative stress-mediated cellular damages in rat skeletal L6 myoblasts. Our results demonstrated that MRWE pretreatment markedly improved cell survival and suppressed cell cycle arrest at the G2/M phase and apoptosis in hydrogen peroxide (H2O2)-treated L6 cells. H2O2-triggered DNA damage was also notably reduced by MRWE, which since it was correlated with protection of reactive oxygen species (ROS) production. Additionally, H2O2 stimulated cytosolic release of cytochrome c and up-regulation of Bax/Bcl-2 ratio, whereas MRWE suppressed these changes following by H2O2. Moreover, MRWE inhibited the cleavage of poly(ADP-ribose) polymerase as well as the activity of caspase-3 by H2O2. Furthermore, MRWE enhanced H2O2-mediated expression of nuclear factor erythroid 2-associated factor 2 (Nrf2) and its representative downstream enzyme, heme oxygenase-1 (HO-1). However, the protective effects of MRWE on H2O2-induced ROS production, cell cycle arrest and apoptosis were significantly attenuated by HO-1 inhibitor. In conclusion, our present results suggests that MRWE could protect L6 myoblasts from H2O2-induced cellular injury by inhibiting ROS generation along with Nrf2-mediated activation of HO-1, indicating this finding may expand the scope of application of Mori Ramulus in medicine.

The herbal composition GGEx18 from Laminaria japonica, Rheum palmatum, and Ephedra sinica reduces obesity via skeletal muscle AMPK and PPARα.

CONTEXT: Since AMP-activated protein kinase (AMPK) activation in skeletal muscle of obese rodents stimulates fatty acid oxidation, it is reasonable to hypothesize that pharmacological activation of AMPK might be of therapeutic benefit in obesity. OBJECTIVE: To investigate the effects of the traditional Korean anti-obesity drug GGEx18, a mixture of three herbs, Laminaria japonica Aresch (Laminariaceae), Rheum palmatum L. (Polygonaceae), and Ephedra sinica Stapf (Ephedraceae), on obesity and the involvement of AMPK in this process. MATERIALS AND METHODS: After high fat diet-induced obese mice were treated with GGEx18, we studied the effects of GGEx18 on body weight, fat mass, skeletal muscle lipid accumulation, and the expressions of AMPK, peroxisome proliferator-activated receptor ά (PPARα), and PPARα target genes. The effects of GGEx18 and/or the AMPK inhibitor compound C on lipid accumulation and expression of the above genes were measured in C2C12 skeletal muscle cells. RESULTS: Administration of GGEx18 to obese mice for 9 weeks significantly (p < 0.05) decreased body and adipose tissue weights compared with obese control mice (p < 0.05). Lipid accumulation in skeletal muscle was inhibited by GGEx18. GGEx18 significantly (p < 0.05) increased skeletal muscle mRNA levels of AMPKα1 and AMPKα2 as well as PPARα and its target genes. Consistent with the in vivo data, GGEx18 inhibited lipid accumulation, and similar activation of genes was observed in GGEx18-treated C2C12 cells. However, compound C inhibited these effects in C2C12 cells. DISCUSSION AND CONCLUSION: These results suggest that GGEx18 improves obesity through skeletal muscle AMPK and AMPK-stimulated expression of PPARα and its target enzymes for fatty acid oxidation.

Potential roles of GABA receptors in morphine self-administration in rats.

It is well established that the reinforcing effect of drugs of abuse is linked to the mesolimbic dopamine (DA) system. Morphine produces an increase in DA release in the brain, which may provide positive reinforcement contributing to the development of motivational aspects of drug-seeking and maintenance behavior. Several studies suggest that the GABA receptor system may play a significant role in the modulating the mesolimbic DA system. The purpose of this study was to investigate potential roles for GABA agonists in morphine self-administration behavior. Male Sprague-Dawley rats were trained to self-administrated morphine (0.1 mg/kg per injection) during daily 1-h sessions under a fixed ratio 1 schedule. Rats received an intravenous injection of the selective GABA(B) antagonist SCH 50911 (2.0 mg/kg) or an intraperitoneal injection of the GABA(A) antagonist bicuculline (1.0 mg/kg), immediately followed by either an intraperitoneal injection of baclofen (1.25 or 1.8 mg/kg) or muscimol (0.5 or 1.0 mg/kg, i.p.), 30 min prior to the start of test session. Results showed that pretreatment with baclofen or muscimol reduced morphine-maintenance response in a dose-dependent fashion and that baclofen and muscimol effects were reversed by injections of SCH 50911 and bicuculline, respectively. These data suggest that activation of both GABA(A) and GABA(B) receptors may be effective in suppressing the reinforcing effects of morphine.

Acupuncture normalizes the release of accumbal dopamine during the withdrawal period and after the ethanol challenge in chronic ethanol-treated rats.

Many studies have shown that acupuncture can contribute to the biochemical balance in the central nervous system and maintenance or recovery of homeostasis. It is well known that chronic administration of ethanol may produce depletion or sensitization of extracellular dopamine levels in the nucleus accumbens. The present study was designed to investigate the effects of acupuncture on chronic ethanol-induced changes in extracellular dopamine levels in the nucleus accumbens shell (using in vivo microdialysis in unanesthetized rats). Male Sprague-Dawley rats were treated with 3 g/kg/day of ethanol (20%, w/v) or saline by intraperitoneal injection for 21 days. Following 72 h of ethanol withdrawal, acupuncture was applied at bilateral Shenmen (HT7) points for 1 min. Different group of rats using the same paradigm of ethanol treatment were acupunctured at the same points after the systemic ethanol challenge (3 g/kg, i.p.). Acupuncture at the specific acupoint HT7, but not at control points (PC6 or tail) significantly prevented both a decrease of extracellular dopamine levels in the nucleus accumbens during ethanol withdrawal and an increase in accumbal dopamine levels induced by the ethanol challenge. These results provided strong evidence that stimulation of the specific acupoint HT7 helps to normalize the release of dopamine in the mesolimbic system following chronic ethanol treatment.

Effect of acupuncture on behavioral hyperactivity and dopamine release in the nucleus accumbens in rats sensitized to morphine.

Acupuncture as a therapeutic intervention has been used for the treatment of many functional disorders including substance abuse. However, there are still many unanswered question about the basic mechanism underlying acupuncture's effectiveness in the treatment of drug addiction. Repeated injection of psycostimulants or morphine can produce behavioral and neurochemical sensitization and have been used as a model for studying drug addiction. The present study was designed to investigate the effect of acupuncture on repeated morphine-induced changes in extracellular dopamine levels using in vivo microdialysis and repeated morphine-induced behavioral changes. Male Sprague-Dawley rats were treated with saline or increasing doses of morphine (10, 20 and 40 mg/kg, s.c., twice daily for 3 days). Following 15 days of withdrawal, acupuncture was applied at bilateral Shenmen (HT7) points for 1 min after the systemic challenge with morphine HCl (5 mg/kg, s.c.). Results showed that acupuncture at the specific acupoint HT7, but not at control points (TE8 and tail) significantly decreased both dopamine release in the nucleus accumbens and behavioral hyperactivity induced by a systemic morphine challenge. These results suggest that the therapeutic effect of acupuncture on morphine addiction occurs through inhibition of neurochemical and behavioral sensitization to morphine.

Saikosaponin a, an active compound of Radix Bupleuri, attenuates inflammation in hypertrophied 3T3-L1 adipocytes via ERK/NF-κB signaling pathways.

Bupleurum falcatum L. is employed in oriental medicine in Korea. This root has been used for anti-inflammatory, anti-pyretic, and anti-hepatotoxic effects in the treatments of common cold, fever, and hepatitis. One of major bioactive compounds of Radix Bupleuri is the saikosaponin a (SSNa). However, little is known concerning the effects of SSNa on obesity associated with a state of low-grade inflammation. Consequently, this study was conducted to determine the inhibition of the inflammation pathway of SSNa in obesity. MTT assay was conducted for cytotoxicity and viability; nuclear and cytoplasmic fractions were extracted from adipocytes for translocation of nuclear factor-κB cells (NF-κB); nitric oxide (NO) production and secretion using Griess reagent; reverse transcription-polymerase chain reaction (RT-PCR) and immunoblotting for mRNA and protein levels associated with inflammation in the hypertrophied adipocytes. The results revealed that SSNa significantly decreased the expression of tumor necrosis factor-α (TNFα), interleukin (IL)-1ß and IL-6 as proinflammatory cytokines, compared to that of non-treated control cells. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as inflammatory factors were reduced by treatment of these cells with SSNa and also suppressed NO production. Phosphorylation of IκBα was inhibited and translocation of NF-κB was suppressed via the ERK pathway in response to SSNa treatment. In conclusion, the results demonstrated that SSNa can inhibit the expression of inflammatory-associated genes in hypertrophied 3T3-L1 adipocytes and is a potent inhibitor of NF-κB activation. Thus these results suggest that SSNa is a novel therapeutic agent against that can be used against obesity-associated inflammation.

Acupuncture attenuates repeated nicotine-induced behavioral sensitization and c-Fos expression in the nucleus accumbens and striatum of the rat.

Repeated injections of nicotine can produce behavioral sensitization, as evidenced by an enhanced locomotor response to a subsequent injection of the drug. Behavioral sensitization has been suggested as a model for studying drug addiction. Acupuncture as a therapeutic intervention is widely used for treatment for many functional disorders, such as substance abuse and mental dysfunction. We examined the effect of acupuncture on nicotine-induced behavioral locomotor activity and c-fos expression in the nucleus accumbens and striatum utilizing the immunocytochemical detection of the Fos protein. The rats were given repeated daily nicotine injections (0.4 mg/kg s.c., twice daily for 7 days) followed by one challenging injection on the 4th day after the last daily injection. Acupuncture at zusanli (ST36), but not control, significantly attenuated expected increase in nicotine-induced locomotor activity and Fos-like-immunoreactivity in the nucleus accumebns and striatum to subsequent nicotine challenge. These findings suggest that acupuncture has a therapeutic effect on nicotine addiction, possibly by modulating postsynaptic neuronal activity in the nucleus accumbens and the striatum.

Acupuncture-mediated inhibition of ethanol-induced dopamine release in the rat nucleus accumbens through the GABAB receptor.

Clinical trials are currently underway to determine the effectiveness of acupuncture in the treatment of drug abuse. However, there are still many unanswered questions about the basic mechanisms of acupuncture. Studies have shown that the GABA(B) receptor system may play a significant modulatory role in the mesolimbic system in drug abuse, including ethanol. The in vivo microdialysis study was designed to investigate the effect of acupuncture on acute ethanol-induced dopamine release in the nucleus accumbens and the potential role of the GABA(B) receptor system in acupuncture. Male Sprague-Dawley rats were administered with the highly selective GABA(B) antagonist SCH 50911 (3 mg/kg, i.p.) 1h prior to an intraperitoneal injection of ethanol (1 g/kg). Immediately after ethanol treatment, acupuncture was given at bilateral Shenmen (HT7) points for 1min. Acupuncture at the specific acupoint HT7, but not at control points (PC6 or tail) significantly decreased dopamine release in the nucleus accumbens. Inhibition of dopamine release by acupuncture was completely prevented by SCH 50911. These results suggest that stimulation of specific acupoints inhibits ethanol-induced dopamine release by modulating GABA(B) activity and imply that acupuncture may be effective in blocking the reinforcing effects of ethanol.

(-)-Epigallocatechin 3-gallate inhibits invasion by inducing the expression of Raf kinase inhibitor protein in AsPC­1 human pancreatic adenocarcinoma cells through the modulation of histone deacetylase activity.

The aim of the present study was to assess whether (-)-epigallocatechin 3-gallate (EGCG) via epigenetic modifications, regulates Raf kinase inhibitor protein (RKIP) expression and invasive metastatic activity in AsPC-1 pancreatic adenocarcinoma cells. Basal levels of RKIP were examined in various human pancreatic cancer cell lines and MTT assay was used to assess cell viability. AsPC-1 cells were treated with EGCG with/without trichostatin A (TSA), as the positive control, for 24 h. The levels of RKIP and histone H3 induction were analyzed by immunoblot analysis. In order to determine the role of RKIP induction in NF-κB translocation and invasive metastatic activity in AsPC-1 cells, we examined NF-κB translocation, invasive metastatic parameters by RT-PCR, metastasis-related proteins by western blot analysis and matrix metalloproteinase (MMP)-2 and -9 activity by gelatin zymography. To validate RKIP induction through the extracellular signal regulated kinase (ERK) pathway, the cells were treated with U0126, an ERK inhibitor. Our results showed that EGCG induced RKIP upregulation via the inhibition of histone deacetylase (HDAC) activity which increased histone H3 expression and inhibited Snail expression, NF-κB nuclear translocation, MMP-2 and -9 activity and Matrigel invasion in AsPC-1 cells. The expression of E-cadherin in the cells was upregulated. The phosphorylation of ERK was decreased by RKIP induction following EGCG treatment. Furthermore, our results confirmed that U0126 treatment repressed ERK phosphorylation and induced RKIP expression. Taken together, our results strongly suggest that EGCG regulates RKIP/ERK/NF-κB and/or RKIP/NF-κB/Snail and inhibits invasive metastasis in the AsPC-1 human pancreatic adenocarcinoma cell line.

[6]-Gingerol Prevents Disassembly of Cell Junctions and Activities of MMPs in Invasive Human Pancreas Cancer Cells through ERK/NF- κ B/Snail Signal Transduction Pathway.

To study the effects of [6]-gingerol, a ginger phytochemical, on tight junction (TJ) molecules, we investigated TJ tightening and signal transduction pathways in human pancreatic duct cell-derived cancer cell line PANC-1. The following methods were utilized: MTT assay to determine cytotoxicity; zymography to examine matrix metalloproteinase (MMP) activities; transepithelial electrical resistance (TER) and paracellular flux for TJ measurement; RT-PCR and immunoblotting for proteins related to TJ and invasion; and EMSA for NF- κ B activity in PANC-1 cells. Results revealed that TER significantly increased and claudin 4 and MMP-9 decreased compared to those of the control. TJ protein levels, including zonula occludens (ZO-) 1, occludin, and E-cadherin, increased in [6]-gingerol-treated cells, which correlated with a decrease in paracellular flux and MMP activity. Furthermore, NF- κ B/Snail nuclear translocation was suppressed via downregulation of the extracellular signal-regulated kinase (ERK) pathway in response to [6]-gingerol treatment. Moreover, treatment with U0126, an ERK inhibitor, completely blocked NF- κ B activity. In conclusion, these findings demonstrate that [6]-gingerol regulates TJ-related proteins and suppresses invasion and metastasis through NF- κ B/Snail inhibition via inhibition of the ERK pathway. Therefore, [6]-gingerol may suppress the invasive activity of PANC-1 cells.

Anticancer constituents from the roots of Rubia cordifolia L.

Activity-directed isolation of the methylene chloride fraction of the roots of Rubia cordifolia L. resulted in the identification of a new epoxymollugin (3) and eight known compounds (1, 2, 4-9). The structures of the compounds were elucidated from chemical and spectroscopic evidence. In addition, their topoisomerase I and II inhibitory activities and cytotoxicities were measured.

The essential oil from Angelica gigas NAKAI suppresses nicotine sensitization.

Behavioral sensitization, as evidenced by the progressive enhanced locomotor response to a subsequent injection of the drug, is the major behavioral outcome produced by repeated injections of nicotine, and a model for studying drug addiction. It is putatively regarded that the alteration of extracellular dopamine release in the nucleus accumbens is closely associated with nicotine-induced behavioral sensitization. The present study was performed to evaluate the effects of the essential oil from Angelica gigas NAKAI (on fragrance inhalation) on repeated nicotine-induced locomotor activity and extracellular dopamine levels in the nucleus accumbens of rats using in vivo microdialysis. Rats were given repeated injections of saline or nicotine (0.4 mg/kg s.c., twice a day for 7 d), followed by one challenge injection on the 4th day after the last daily injection. Systemic challenge with nicotine (0.4 mg/kg s.c.) produced a larger increase in locomotor activity in nicotine-pretreated rats than in saline-pretreated rats. A direct local challenge of 3 mM nicotine via a microdialysis probe also induced a larger increase in dopamine release in nicotine-pretreated rats than in saline-pretreated rats. Most importantly, our results showed that inhalation of the essential oils from Angelica gigas NAKAI significantly decreased both dopamine release in the nucleus accumbens and locomotor activity induced by a nicotine challenge. These results suggest that the essential oils from Angelica gigas NAKAI inhibit nicotine-induced behavioral and neurochemical sensitization, and imply that the essential oil from Angelica gigas NAKAI may be effective in treating nicotine addiction, possibly by modulating dopamine release in the nucleus accumbens.