Dehydroeffusol inhibits gastric cancer cell growth and tumorigenicity by selectively inducing tumor-suppressive endoplasmic reticulum stress and a moderate apoptosis.

Gastric cancer is ranked as the third leading cause of cancer-related death in the world. Although extensive efforts have been made in recent decades to treat gastric cancer with various anticancer drugs, effective anti-gastric cancer therapeutics to cure the disease are still lacking in the clinics. Therefore, potent novel anti-gastric cancer drugs are greatly needed. In this study, we explored a novel anti-gastric cancer agent from a medicinal herb named Juncus effusus and found that the active component dehydroeffusol (DHE), a small molecular phenanthrene, effectively inhibited gastric cancer cell proliferation and tumorigenesis by inducing tumor suppressive endoplasmic reticulum (ER) stress and by triggering moderate apoptosis. Mechanistic studies revealed that DHE selectively activated the intracellular tumor suppressive stress response by promoting the overexpression of the key ER stress marker DNA damage-inducible transcript 3 (DDIT3), through upregulation of activating transcription factor 4 (ATF4). Concurrently, DHE suppressed the expression of the cell survival and ER stress marker glucose regulated protein of molecular mass 78 (GRP78) via downregulation of the transcription factor ATF6. In addition, DHE markedly activated the stress response signaling pathway MEKK4-MKK3/6-p38-DDIT3, but significantly inhibited ERK signaling. Our data suggest that DHE inhibits gastric cancer cell growth and tumorigenicity through selectively inducing a robust tumor suppressive ER stress response and a moderate apoptosis response. Therefore, DHE may provide a novel drug candidate for further development of potential anti-gastric cancer therapeutics.

Dehydroeffusol effectively inhibits human gastric cancer cell-mediated vasculogenic mimicry with low toxicity.

Accumulated data has shown that various vasculogenic tumor cells, including gastric cancer cells, are able to directly form tumor blood vessels via vasculogenic mimicry, supplying oxygen and nutrients to tumors, and facilitating progression and metastasis of malignant tumors. Therefore, tumor vasculogenic mimicry is a rational target for developing novel anticancer therapeutics. However, effective antitumor vasculogenic mimicry-targeting drugs are not clinically available. In this study, we purified 2,7-dihydroxyl-1-methyl-5-vinyl-phenanthrene, termed dehydroeffusol, from the traditional Chinese medicinal herb Juncus effusus L., and found that dehydroeffusol effectively inhibited gastric cancer cell-mediated vasculogenic mimicry in vitro and in vivo with very low toxicity. Dehydroeffusol significantly suppressed gastric cancer cell adhesion, migration, and invasion. Molecular mechanistic studies revealed that dehydroeffusol markedly inhibited the expression of a vasculogenic mimicry master gene VE-cadherin and reduced adherent protein exposure on the cell surface by inhibiting gene promoter activity. In addition, dehydroeffusol significantly decreased the expression of a key vasculogenic gene matrix metalloproteinase 2 (MMP2) in gastric cancer cells, and diminished MMP2 protease activity. Together, our results showed that dehydroeffusol effectively inhibited gastric cancer cell-mediated vasculogenic mimicry with very low toxicity, suggesting that dehydroeffusol is a potential drug candidate for anti-gastric cancer neovascularization and anti-gastric cancer therapy.

Glaucocalyxin A activates FasL and induces apoptosis through activation of the JNK pathway in human breast cancer cells.

THis study was conducted to analyze the molecular mechanisms responsible for anti-proliferation effects of glaucocalyxin A in cultured MCF-7 and Hs578T breast cancer cells. The concentration that reduced cell viability to 50% (IC50) after 72 h treatment was derived and potential molecular mechanisms of anti-proliferation using the IC50 were investigated as changes in cell cycle arrest and apoptosis. Gene and protein expression changes related to apoptosis were investigated by semi-quantitative RT-PCR and western blotting, respectively. Involvement of phosphorylated mitogen-activated protein kinases and JNK signaling in regulation of these molecules was characterized by western blotting. Cell viability decreased in a concentration-dependent manner and the IC50 was determined as 1 µM in MCF-7 and 4 µM in Hs578T cell. Subsequently, we demonstrated that the GLA-induced MCF-7 and Hst578T cell death was due to cell cycle arrest at the G2/M transition and was associated with activation of the c-jun N-terminal kinase (JNK) pathway. We conclude that GLA has the potential to inhibit the proliferation of human breast cancer cells through the JNK pathway and suggest its application forthe effective therapy for patients with breast cancer.

[Effect of compound panax notoginsenoside granules on TGF-ß1/Smads signaling pathway in rats with bleomycin-induced pulmonary fibrosis].

OBJECTIVE: To investigate the intervention effects and mechanisms of the compound panax notoginsenoside granules (CPNG) on bleomycin-induced pulmonary fibrosis in rats. METHODS: Sixty male Sprague-Dawley rats were randomly divided into 6 groups, including normal control group, model group, prednisolone group, and CPNG (high, middle and low-dose) groups. Each group included 10 Sprague-Dawley rats. Except the control group, pulmonary fibrosis model rats were injected with bleomycin (5 mg/kg) via trachea. On the second day of the bleomycin injection, the rats in each treatment group were given prednisolone (3.33 mg/kg) and corresponding doses of CPNG (100, 50, 25 mg/kg) by nasogastric feeding daily; the normal control group and the model group were given the equal volume distilled water daily. Twenty-eight days later, all rats were executed and the lung tissues were subjected to the histopathological examination via HE and Masson staining. The hydroxyproline (HYP) in lung tissues was assessed by alkaline hydrolysis. The expressions of TGF-ß1, Smad2, and Smad7 proteins were analyzed by Western blotting. RESULTS: Compared with the model group, the histopathological results revealed that CPNG dramatically decreased the severity of lung inflammation and fibrosis in rats (P<0.01). Compared with the control group, the HYP in lung tissues was reduced in all of the CPNG groups (P<0.01). Moreover, CPNG inhibited the expressions of TGF-ß1 or Smad2 proteins (P<0.01), but enhanced the expression of Smad7 protein in the rat lung tissues (P<0.01). CONCLUSION: CPNG has the prevention and treatment effect on the bleomycin-induced pulmonary fibrosis in rats, and it might be attributed to the regulation on the TGF-ß1/Smads signaling pathway.

Protective effect of apigenin on mouse acute liver injury induced by acetaminophen is associated with increment of hepatic glutathione reductase activity.

Apigenin, a natural plant flavone, has many beneficial effects, but there is no report about treatment of acetaminophen-induced liver injury. Our aim was to examine the protective effect of apigenin on acetaminophen-induced mouse acute liver injury and to investigate the potential mechanisms. A mouse model with acute liver injury was induced by intraperitoneally given acetaminophen 350 mg kg(-1) after oral administration of apigenin 100 and 200 mg kg(-1) for 7 days. The results showed that after treatment with apigenin, the levels of serum alanine aminotransferase and aspartate aminotransferase were gradually decreased, and the severity of liver injury was decreased. In particular, significant changes in liver necrosis were observed in the apigenin 200 mg kg(-1) group. Apigenin could gradually increase the hepatic glutathione reductase (GR) activity and reduced glutathione (GSH) content, and decrease the hepatic malondialdehyde content, but the activities of glutathione peroxidase and glutathione S-transferase in hepatic tissues between the model group and the apigenin-treated groups were not significantly different. It was concluded that apigenin could protect against acetaminophen-induced acute liver injury in mice, and the mechanisms might be associated with enhancing hepatic GSH content via increment of GR activity.

Effects of triterpenic acid from Prunella vulgaris L. on glycemia and pancreas in rat model of streptozotozin diabetes.

BACKGROUND: The effects of triterpenic acid from Prunella vulgaris L. (TAP) on diabetes and its mechanism are uncertain. The aim of this study was to investigate the effects of TAP on antihyperglycemic, antioxidant, and pancreas-protective in streptozotozin (STZ)-diabetic rats. METHODS: The diabetic model was produced by injection of 60 mg/kg STZ. Blood was drawn from the tail vein of rats after 72 hours. Rats with blood glucose ≥ 16.7 mmol/L were considered diabetic. Diabetic rats were randomly divided into four groups: (1) Diabetes rat (STZ), (2) Diabetic rats treated with 50 mg/kg of triterpenic acid from Prunella vulgaris L (STZ + TAP50), (3) Diabetic rats treated with 100 mg/kg TAP (STZ + TAP100), and (4) Diabetic rats treated with 200 mg/kg TAP (STZ + TAP200). Normal rats (n = 10) acted as the control group (NC). TAP was administered by the intragastric route once each day for six weeks. Body weight and the concentration of blood glucose (BG) were measured after three and six weeks. Fructosamine (FMN), malondialdehyde (MDA), and nitric oxide (NO), and the activities of nitric oxide synthase (NOS) and superoxide dismutase (SOD) in serum were determined after six weeks using commercially available kits following the manufacturer's instructions. Pathologic changes in pancreatic ß-cells were also investigated by microscopic examination after hematoxylin-eosin (HE) staining. The level of SOD mRNA in pancreatic ß-cells was measured by polymerase chain reaction (PCR). RESULTS: The levels of BG, FMN, NO, and MDA and the activities of NOS in serum in the four diabetes groups were significantly increased compared with the control group (P < 0.01). The activity of SOD in serum and the body weight was significantly decreased compared with the control group (P < 0.01). After administration of TAP to diabetic rats for six weeks, the body weight and the levels of BG, FMN, MDA, NO and the activity of NOS in serum decreased significantly compared with the STZ group in a dose-dependent manner. The activity of SOD in serum and body weight increased significantly compared with the STZ group in a dose-dependent manner. In addition, diabetic rats showed a significant decrease in SOD mRNA expression in pancreatic ß cells. However, these changes were reversed by TAP. Histopathological examination also showed the protective effect of TAP on pancreatic ß cells. CONCLUSIONS: Triterpenic acid from Prunella vulgaris L. has an anti-diabetic effect, by controlling blood glucose and antioxidants, and has a protective effect on the pancreas.

Baicalein attenuates bleomycin-induced pulmonary fibrosis in rats through inhibition of miR-21.

Currently, there is no satisfactory treatment for pulmonary fibrosis, and effective agents urgently need to be developed. The aim of the present study was to investigate the effects of baicalein on bleomycin-induced pulmonary fibrosis, and the novel mechanisms involved in the anti-fibrosis effects. Pulmonary fibrosis was induced by a single intratracheal instillation of 5 mg/kg bleomycin. Two bleomycin-treated groups were orally administered daily with 50 and 100 mg/kg of baicalein from day 1 to 28. The results showed baicalein decreased hydroxyproline content and α-SMA levels and increased lung index. Histopathological examinations demonstrated baicalein could obviously lower the degree of alveolitis and lung fibrosis. The total antioxidant capacity in bleomycin-treated rats with baicalein was also remarkably higher than in those without baicalein. Baicalein remarkably decreased miR-21 levels and inhibited the increased expression of TGF-ß1 and p-Smad-2/3 in bleomycin-treated rats. Baicalein can attenuate bleomycin-induced pulmonary fibrosis. The attenuation is partly achieved by improving antioxidant activity, alleviating inflammation, repressing miR-21, and inhibiting TGF-ß/Smad signaling.

Rapamycin protects the mitochondria against oxidative stress and apoptosis in a rat model of Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease, in which oxidative stress and mitochondrial dysfunction are responsible for neuronal apoptosis. Rapamycin plays a crucial role in reducing oxidative stress and protecting the mitochondria. However, its protective role in PD has not yet been fully elucidated. In this study, we report that pre-treatment with rapamycin provides behavioral improvements, protects against the loss of dopaminergic neurons, and alleviates mitochondrial ultrastructural injuries in a rat model of PD. Peroxide levels were lower and antioxidant activities were higher in PD rats pre-treated with rapamycin compared to the PD rats pre-treated with the vehicle. Furthermore, pre-treatment with rapamycin significantly elevated the expression of anti-apoptotic markers and reduced the levels of pro-apoptotic markers compared to pre-treatment with the vehicle. In conclusion, our results demonstrated that rapamycin reduced oxidative stress and alleviated mitochondrial injuries in the 6-hydroxydopamine (6-OHDA)-induced rat model of PD, which may subsequently contribute to its anti-apoptotic effects. The ability of rapamycin to exhibit neuroprotection in a rat model of PD may be related to its antioxidant capabilities.

Epigallocatechin gallate, the major component of polyphenols in green tea, inhibits telomere attrition mediated cardiomyocyte apoptosis in cardiac hypertrophy.

BACKGROUND: Telomere signaling plays a role in regulating cardiomyocyte apoptosis during cardiac dysfunction. In this study, we investigated the effects of epigallocatechin gallate (EGCG), the major component of polyphenols in green tea, on telomere dependent apoptotic signal in pressure overload cardiac hypertrophy. METHODS AND RESULTS: Cardiac hypertrophy in rats was established by abdominal aortic constriction (AC). EGCG 50, 100 mg/kg, quercetin (Que) 100mg/kg, captopril (Cap) 50mg/kg, losartan (Los) 30 mg/kg and carvedilol (Carv) 30 mg/kg was intragastrically administered for 6 weeks. Three, five and 7 weeks after aortic constriction, the heart weight indices increased progressively. Malondialdehyde (MDA) contents progressively increased, while superoxide dismutase (SOD) activities decreased. Progressive cardiomyocyte apoptosis and telomere attrition were also found. Although no significant alteration of telomerase reverse transcriptase (TERT) mRNA was found till 7 weeks after aortic constriction, progressive upregulation of p53, c-myc and downregulation of bcl-2, telomere repeat-binding factor 2(TRF(2)) were seen. EGCG, quercetin, captopril, losartan and carvedilol markedly reduced heart weight indices and apoptotic cardiomyocyte in hypertrophic myocardium, but they had different effects on apoptotic related proteins bcl-2, p53 and c-myc. EGCG, quercetin and carvedilol, have potent antioxidant effects as evidenced by reduction of MDA contents and resumption of SOD activities. EGCG, quercetin and carvedilol could prevent telomere attrition and telomere repeat-binding factor 2 (TRF(2)) loss remarkably, whereas captopril and losartan had no effect on oxidative stress and telomere signal. CONCLUSIONS: Pressure overload induced cardiac hypertrophy initiates oxidative stress, induces telomere repeat-binding factor 2 loss and accelerates telomere shortening in hypertrophic myocardium. EGCG, quercetin and carvedilol with potent antioxidant effect, may inhibit cardiac myocyte apoptosis by preventing telomere shortening and telomere repeat-binding factor 2 (TRF(2)) loss.

Evidence for a therapeutic effect of Braintone on ischemic brain damage.

This study used a novel combination of in vivo and in vitro experiments to show that Braintone had neuroprotective effects and clarified the molecular mechanisms underlying its efficacy. The Chinese herbal extract Braintone is composed of Radix Rhodiolase Essence, Radix Notoginseng Essence, Folium Ginkgo Essence and Rhizoma Chuanxiong. In vivo experiments showed that cerebral infarction volume was reduced, hemispheric water content decreased, and neurological deficits were alleviated in a rat model of permanent middle cerebral artery occlusion after administration of 87.5, 175 or 350 mg/kg Braintone for 7 consecutive days. Western blot analysis showed that Braintone enhanced the expression of hypoxia-inducible factor 1α, heme oxygenase-1 and vascular endothelial growth factor in the ischemic cortex of these rats. The 350 mg/kg dose of Braintone produced the most dramatic effects. For the in vitro experiments, prior to oxygen-glucose deprivation, rats were intragastrically injected with 440, 880 or 1 760 mg/kg Braintone to prepare a Braintone-containing serum, which was used to pre-treat human umbilical vein endothelial cells for 24 hours. Human umbilical vein endothelial cell injury was alleviated with this pre-treatment. Western blot and real-time PCR analysis showed that the Braintone-containing serum increased the levels of hypoxia-inducible factor 1α mRNA and protein, heme oxygenase-1 protein and vascular endothelial growth factor mRNA in oxygen-glucose deprived human umbilical vein endothelial cells. The 1 760 mg/kg dose produced the greatest increases in expression. Collectively, these experimental findings suggest that Braintone has neuroprotective effects on ischemia-induced brain damage via the up-regulation of hypoxia-inducible factor 1α, heme oxygenase-1 and vascular endothelial growth factor expression in vascular endothelial cells.

Reduction of rat cardiac hypertrophy by osthol is related to regulation of cardiac oxidative stress and lipid metabolism.

The objective of this study was to examine the therapeutic effect of osthol, a coumarin compound isolated from the fruit of Cnidium monnieri (L.) Cusson, on cardiac hypertrophy in rats and investigate its potential mechanisms. The rats with cardiac hypertrophy induced by renovascular hypertension were given osthol orally by gavage for 4 weeks. The results showed that in the osthol 20 mg/kg group, the blood pressure, heart weight index and myocardial malondialdehyde content were lowered (p < 0.001, p = 0.002 and p = 0.025, respectively), the myocardial superoxide dismutase and glutathione peroxidase contents were increased (p < 0.001), and the elevated unesterified fatty acids and triacylglycerols in myocardial tissues were decreased (p = 0.017 and p = 0.004, respectively). At the same time, the myocardial peroxisome proliferator-activated receptor (PPAR)-α and carnitine palmitoyltransferase (CPT)-1a mRNA expressions were increased and the myocardial diacylglycerol acyltransferase (DGAT) mRNA expression was decreased in the osthol 20 mg/kg group (p < 0.001). Osthol treatment was associated with a decreased cross-sectional area of cardiomyocytes (p < 0.001). These findings suggest that osthol may exert a therapeutic effect on cardiac hypertrophy in rats, and its mechanisms may be related to the improvement of myocardial oxidative stress and lipid metabolism via regulation of PPARα-mediated target gene expressions including an increase in CPT-1a mRNA expression and a decrease in DGAT mRNA expression.

[Effects of ketamine and alcohol on learning and memory impairment in mice].

OBJECTIVE: To study the effects of ketamine and alcohol on learning and memory in mice and its possible mechanism. METHODS: Forty mice were divided into 4 groups: normal control group, ketamine group, alcohol group, and alcohol plus ketamine group. Ketamine and alcohol were given by intraperitoneal injection and intragastric administration, respectively, 1 time per day, for 14 days. The ability of learning and memory in mice was tested by the method of step-down and Morris water maze. Acetylcholine (ACh) and 5-hydroxy tryptamine(5-HT) in mice brain tissue were analyzed for the possible mechanism. RESULTS: (1) Step-down: The treatment groups lessened the latency and added wrong times (P < 0.05). The number of errors in the combined treatment group significantly increased comparing with the single drug treatment group (P < 0.05). (2) Morris water-maze: The treatment groups prolonged the latency (P < 0.05), reduced the target quadrant activity time significantly (P < 0.05), and decreased the numbers of crossing the former platform significantly (P < 0.05). (3) Biochemical index determination: The concentrations of ACh and 5-HT in treatment groups decreased significantly (P < 0.05), showed a more decreasement comparing with the single drug treatment group. CONCLUSION: Ketamine has a synergistic effect with alcohol on learning and memory impairment in mice, which may be related to the common inhibitive effect on the ACh and 5-HT.

Protective effect of flavonoids from Astragalus complanatus on radiation induced damages in mice.

This study aimed to evaluate the radioprotective effect of flavonoids extracted from the seeds of Astragalus complanatus R.Br. (FAC) and their protective mechanism against radiation damage. FAC increased the survival rate of mice and made the damaged organ injured by (60)Co γ-irradiation recovered to normal appearance with the mechanism of enhancing immune function and blood-producing function in vivo. The molecule mechanism of FAC against radiation is involved in the reduction of DNA injury and mutation in vitro. Eleven monomers of the FAC were analyzed by HPLC. These results seem to support the use of FAC in relieving radiation damage.

[Effects of ketamine on proliferation and apoptosis of pheochromocytoma cell].

OBJECTIVE: To explore the effect of ketamine on adrenal pheochromocytoma (PC12) cell proliferation inhibition and induction of apoptosis and its mechanism. METHODS: PC12 cells of rats were models for dopaminergic neuron. PC12 cells were cultured with ketamine at concentrations of 0.9, 1.2, 1.5, 1.8 and 2.1 mmol/L, respectively. The cell viability was measured by MTT method after incubation at 12, 24, 48 and 72h. Hoechst stain was used to observe the morphological changes of apoptosis. PC12 cells cultured after 48 h with different concentrations of ketamine were selected to detect apoptotic rate using flow cytometry and detect the expression of bax and bcl-2 proteins using Western blotting. RESULTS: For different concentrations of ketamine, vitality of PC12 cells significantly decreased with increase of the incubation time. Apoptosis was obviously observed using Hoechst staining. Flow cytometry showed that apoptosis rates significantly increased with increasing ketamine concentrations. CONCLUSION: Ketamine can inhibit the proliferation of PC12 cell by inducing apoptosis of the PC12 cell in a concentrations-dependent manner. The underlying mechanism may be related to promoting the expression of bax and inhibiting the expression of bcl-2 in the cells.

Ursolic acid induces human hepatoma cell line SMMC-7721 apoptosis via p53-dependent pathway.

BACKGROUND: Ursolic acid (UA) is a ubiquitous molecule in the plant kingdom with specific anticancer effects that have been shown in vitro and in vivo. Although UA can inhibit the proliferation of liver cancer cells and induce apoptosis of many types of tumor cells, the molecular mechanism of its anti-hepatoma activity is still not well defined. The objective of this study was to investigate the inhibitory effect and mechanisms of UA on the human hepatoma cell line SMMC-7721. METHODS: After treatment with UA, the growth inhibition of SMMC-7721 cells was assessed by MTT assay. Cells were also evaluated by flow cytometric analysis, Wright-Giemasa staining, Hoechst 33258 staining and transmission electron microscope after they were induced by UA. DNA microarray technology was used to investigate the gene expression pattern of SMMC-7721 cells exposed to UA 40 micromol/L. The molecular mechanism of cells death was analyzed by real-time RT-PCR and Western blotting. RESULTS: The proliferation of SMMC-7721 cells was significantly inhibited in a dose- and time-dependent manner after UA treatment. UA induced cell cycle arrest and apoptosis. The DNA microarray analysis indicated that 64 genes were found to be markedly up- or down-expressed, including GDF15, SOD2, ATF3, and fos. The result of Western blotting showed the apoptotic proteins p53 and Bax were up-regulated while the anti-apoptotic protein Bcl-2 was down-regulated. Real-time RT-PCR confirmed UA could up-regulate the mRNA expressions of GDF15, SOD2, ATF3 and down-regulate the mRAN expression of fos. Meanwhile these effects were partly blocked by pretreatment with the p53 inhibitor Pft-alpha. CONCLUSION: Activation of the p53 pathway is involved in UA inhibition of SMMC-7721 human hepatocellular carcinoma cell growth and induction of apoptosis.

Epigallocatechin gallate protects H9c2 cardiomyoblasts against hydrogen dioxides- induced apoptosis and telomere attrition.

Epigallocatechin gallate (EGCG), the major component of polyphenols in green tea, has recently attracted considerable attention for its cardioprotective effects. Telomere signalling plays a role in regulating cardiomyocyte apoptosis during cardiac dysfunction. The purpose of this study was to investigate the effects of EGCG on oxidative stress-induced apoptosis and telomere attrition in cardiomyocytes. H9c2 cells were incubated with EGCG, 50 and 100 mg/l, for 24 h. Apoptosis induced by 200 micromol/l hydrogen dioxide (H(2)O(2)) was analyzed by DAPI nuclear staining, electron microscopy, electrophoresis of DNA fragments and flow cytometry. When H9c2 cells were incubated with H(2)O(2) for 12-24 h, the intracellular and extracellular H(2)O(2) concentrations were not affected by the presence of EGCG. Chromatin condensation, DNA fragmentation and apoptotic body formation were observed in H(2)O(2)-induced injury. Flow cytometry analysis showed that the apoptotic rate increased remarkably. EGCG significantly inhibited H(2)O(2)-induced apoptotic morphological changes and apoptotic rate. When H9c2 cells were incubated with H(2)O(2), the telomere length shortened and the protein expression of telomere repeat-binding factor 2 (TRF(2)) decreased gradually, while the protein levels of p53 and p21 increased. EGCG significantly inhibited telomere attrition, TRF(2) loss and p53, p21 upregulation induced by H(2)O(2). These results suggested that EGCG might suppress oxidative stress-induced cardiomyocyte apoptosis through inhibiting telomere dependent apoptotic pathway.

[The correlation between ketamine-induced schizophrenia-like signs in mice and the expressions of NRG1, ErbB4 mRNA].

OBJECTIVE: To explore the correlation between signs similar to schizophrenia in mice after ketamine administration and the expressions of NRG1 and ErbB4 mRNA in order to explain the possible pathogenesis of schizophrenia. METHODS: Fifty KM mice were randomly divided into 5 groups which were administered intraperitoneally with saline, clozapine and different dosages ketamine. The ketamine groups were administered intraperitoneally with low dosage (25 mg/kg), middle dosage (50 mg/kg) and high dosage (100 mg/kg) one time every day for 7 days. After administration of 100 mg/kg ketamine for 7 days, the clozapine group was introgastrically administered 20 mg/kg with clozapine one time every day for 7 days. The pathological changes of hippocampus neurons were observed by HE stain. The expressions of the NRG1 and ErbB4 mRNA in hippocampus were detected by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: In the group with high dosage of ketamine, the levels of NRG1 and ErbB4 mRNA were significantly lower than that of the group with saline. CONCLUSION: Ketamine may induce signs similar to schizophrenia in KM mice. The mechanism may be involved in the reduction of NRG1 and ErbB4 mRNA expression.

[Behavior study of ketamine-induced symptoms similar to schizophrenia in mice].

OBJECTIVE: To observe the symptoms similar to schizophrenia in mice after ketamine single or continuous injection and to evaluate the feasibility of schizophrenia model injected with different dose of ketamine. METHODS: A total of 40 male mice were randomly divided into 4 groups, which were injected intraperitoneally with physiological saline (control group), 25 mg/kg ketamine (low dose group), 50 mg/kg ketamine (middle dose group), and 100 mg/kg ketamine (high dose group) qd for 7 days continuously. The behavior changes of mice were observed. RESULTS: Hyperactivity, stereotyped behavior and ataxia (P < 0.01) were observed in high dose group after single injection. After continuous injection of ketamine for 7 days, the middle dose group showed hyperactivity, stereotyped behavior and ataxia (P < 0.05), stereotyped behavior and ataxia were more significant in high dose group (P < 0.01). CONCLUSION: Ketamine can induce the symptoms similar to schizophrenia in mice after single or continuous injection. The symptoms induced by high dose ketamine will be more prominent and stable after continuous injection.

[Advances in research of ketamine addiction mechanism].

Ketamine is a phencyclidine derivative acting primarily as a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) excitatory glutamate receptors. As a common intravenous anaesthetic in clinic, it is also increasingly abused because of its hallucination and addiction effects. Based on the pharmacological and toxicologic characteristics of ketamine and the acknowledged addiction mechanism of other abused drugs, this article reviews the possible addiction mechanism of the ketamine in the aspects of its enhanced effects and reward systems, the anatomic structures, the related receptors and the individual differences.

Induction of apoptosis in human hepatocarcinoma SMMC-7721 cells in vitro by flavonoids from Astragalus complanatus.

AIM OF THE STUDY: Flavonoids extracted from the seeds of Astragalus complanatus R.Br. reduce the proliferation of many cancer cells. The present study was carried out to evaluate the effects of these flavonoids from Astragalus complanatus (FAC) on human hepatocarcinoma cell viability and apoptosis and to investigate its mechanisms of action in SMMC-7721 cells. MATERIALS AND METHODS: Cell viability was measured using the MTT assay. To detect apoptotic cells, SMMC-7721 cells treated with FAC were stained with Hoechst 33258 and subjected to agarose gel electrophoresis. Quantitative detection of apoptotic cells was performed by flow cytometry. The effects of FAC on apoptosis and cell cycle regulatory genes and proteins in SMMC-7721 cells were examined using an S series apoptosis and cell cycle gene array and Western blot analysis. RESULTS: The growth of SMMC-7721 and HepG2 cells was inhibited by treatment with FAC. Cell death induced by FAC was characterized by nuclear condensation and DNA fragmentation. Moreover, the cell cycle was arrested in the G0/G1 and S phases in FAC-treated SMMC-7721 cells. A sub-G1 peak with reduced DNA content was also formed. The activity of caspase-3 was significantly increased following FAC treatment. Microarray data indicated that the expression levels of 76 genes were changed in SMMC-7721 cells treated with FAC: 35 genes were up-regulated and 41 were down-regulated. Western blot analysis showed that caspase-3, caspase-8, Bax, P21, and P27 protein levels in SMMC-7721 cells were increased after 48 h of FAC treatment, while cyclinB1, cyclinD1, CDK1, and CDK4 protein levels were decreased. CONCLUSIONS: These results suggest that FAC may play an important role in tumor growth suppression by inducing apoptosis in human hepatocarcinoma cells via mitochondria-dependent and death receptor-dependent apoptotic pathways.