Astaxanthin pretreatment attenuates acetaminophen-induced liver injury in mice

BackgroundAcetaminophen (APAP) is a conventional drug widely used in the clinic because of its antipyretic-analgesic effects. However, accidental or intentional APAP overdoses induce liver injury and even acute liver failure (ALF). Astaxanthin (ASX) is the strongest antioxidant in nature that shows preventive and therapeutic properties, such as ocular protection, anti-tumor, anti-diabetes, anti-inflammatory, and immunomodulatory effects. The aim of present study was to determine whether ASX pretreatment provides protection against APAP-induced liver failure.MethodsMale C57BL/6 mice were randomly divided into 7 groups, including control, oil, ASX (30 mg/kg or 60 mg/kg), APAP and APAP + ASX (30 mg/kg or 60 mg/kg) groups. Saline, olive oil and ASX were administered for 14 days. The APAP and APAP + ASX groups were given a peritoneal injection of 700 mg/kg or 300 mg/kg APAP to determine the 5-day survival rate and for further observation, respectively. Blood and liver samples were collected to detect alanine transaminase (ALT), aspartate transaminase (AST), inflammation, oxidative stress and antioxidant systems, and to observe histopathologic changes and key proteins in the mitogen-activated protein kinase (MAPK) family.ResultsASX pretreatment before APAP increased the 5-day survival rate in a dose-dependent manner and reduced the ALT, AST, hepatic necrosis, reactive oxygen species (ROS) generation, lipid peroxidation (LPO), oxidative stress and pro-inflammatory factors. ASX protected against APAP toxicity by inhibiting the depletion of glutathione (GSH) and superoxide dismutase (SOD). Administration of ASX did not change the expression of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and P38. However, phosphorylation of JNK, ERK and P38 was reduced, consistent with the level of tumor necrosis factor alpha (TNF-α) and TNF receptor-associated factor 2 (TRAF2).ConclusionASX provided protection for the liver against APAP hepatotoxicity by alleviating hepatocyte necrosis, blocking ROS generation, inhibiting oxidative stress, and reducing apoptosis by inhibiting the TNF-α-mediated JNK signal pathway and by phosphorylation of ERK and P38, which made sense in preventing and treating liver damage.     

Glutathione S-transferase A1 (GSTA1) release,an early indicator of acute hepatic injury in mice

Three acute hepatic injury models (a CCl₄-induced model, APAP-induced model and ethanol-induced model) in mice were used to study the importance of GSTA1 in acute hepatic injury by comparison with a standard enzyme marker, alanine aminotransferase (ALT). GSTA1 release was demonstrated to be an earlier and more sensitive indicator of hepatotoxicity than was ALT. Significant increases in GSTA1 were detected at 2 h after CCl₄ exposure, while ALT was undetected at this time. GSTA1 was also a more sensitive indicator of hepatotoxicity than ALT after 6 h. In the APAP and ethanol models, GSTA1 was markedly increased earlier than ALT, at 2 h post exposure. The release of GSTA1 was significantly increased at a dose of 12.5 mg/kg (CCl₄ model), 100 mg/kg (APAP model) and 10 ml/kg (ethanol model), the lowest exposure concentration for each model. In contrast, AST release was not statistically significant. These results suggest that GSTA1 can be detected at low concentrations during the early stages of acute hepatic injury and that GSTA1 is a more sensitive and more accurate indicator than ALT.     

Protective effects of nicotinamide against acetaminophen-induced acute liver injury

Nicotinamide (NAM), the amide form of vitamin B3, is involved in a wide range of biological processes. Recent evidence revealed the anti-inflammatory and anti-oxidant properties of NAM and suggests it may be used as a novel strategy in the prevention of acute liver injury. In the present study, we investigated the potential protective effects of NAM on acetaminophen (APAP)-induced acute liver injury in mice. Mice were treated with NAM at 400 mg/kg 30 min before or after administration of APAP at a hepatotoxic dose of 400 mg/kg body weight via intraperitoneal injection. Liver injury and the expression of inflammation-related molecules were determined by histological examination and biochemical analysis, respectively. In addition, the survival rate of mice was assessed after APAP administration. Pretreatment with NAM for 30 min significantly decreased plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and malondialdehyde (MDA), and diminished histopathologic evidence of hepatic toxicity in mice following APAP administration. Similarly, posttreatment with NAM also decreased plasma ALT and AST levels in APAP-administrated mice. Furthermore, both pretreatment and posttreatment with NAM prolonged the survival rate of acute liver injury mice, accompanied by a significant reduction in the plasma levels of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ), and interleukin-6 (IL-6). Together, these findings suggest that NAM possesses protective effects on APAP-induced liver injury, which may involve the anti-inflammatory action.     

D1-like receptor activation improves PCP-induced cognitive deficits in animal models: Implications for mechanisms of improved cognitive function in schizophrenia

Phencyclidine (PCP) produces cognitive deficits of relevance to schizophrenia in animal models. The aim was to investigate the efficacy of the D₁-like receptor agonist, SKF-38393, to improve PCP-induced deficits in the novel object recognition (NOR) and operant reversal learning (RL) tasks. Rats received either sub-chronic PCP (2 mg/kg) or vehicle for 7 days, followed by a 7-day washout. Rats were either tested in NOR or the RL tasks. In NOR, vehicle rats successfully discriminated between novel and familiar objects, an effect abolished in PCP-treated rats. SKF-38393 (6 mg/kg) significantly ameliorated the PCP-induced deficit (P < 0.01) an effect significantly antagonised by SCH-23390 (0.05 mg/kg), a D₁-like receptor antagonist (P < 0.01). In the RL task sub-chronic PCP significantly reduced performance in the reversal phase (P < 0.001); SKF-38393 (6.0 mg/kg) improved this PCP-induced deficit, an effect antagonised by SCH-23390 (P < 0.05). These results suggest a role for D₁-like receptors in improvement of cognitive function in paradigms of relevance to schizophrenia.     

The beneficial effects of ozone therapy in acetaminophen-induced hepatotoxicity in mice

Background

The aim of the present study was to determine the therapeutic effects of medical ozone therapy on acute acetaminophen (APAP)-induced hepatotoxicity which were not clearly demonstrated in prior studies.

Activity of aminocandin (IP960; HMR3270) compared with amphotericin B,itraconazole, caspofungin and micafungin in neutropenic murine models of disseminated infection caused by itraconazole-susceptible and -resistant strains of Aspergillus fumigatus

Aminocandin (IP960; HMR3270; NXL201) is a new echinocandin with broad-spectrum in vitro activity against Aspergillus and Candida spp. We compared the activity of aminocandin with that of amphotericin B (AmB), itraconazole (ITC) and caspofungin (CAS) in murine models of disseminated aspergillosis against three strains of A. fumigatus, two of which were fully susceptible (AF293 and A1163) and one was resistant to ITC (AF91). Mice were rendered temporarily neutropenic or persistently neutropenic with cyclophosphamide and were infected intravenously 3 days later. Temporarily neutropenic mice were treated with either intraperitoneal (i.p.) AmB (5 mg/kg/dose), oral (p.o.) ITC (25 mg/kg/dose), intravenous (i.v.) aminocandin (0.25–10 mg/kg/dose), i.p. aminocandin (1 mg/kg/dose) or solvent control for 9 days. Mice were euthanised 11 days post infection and the kidneys and liver were removed for quantitative culture. Following infection with AF293, only aminocandin 5 mg/kg i.v. yielded 100% survival. Aminocandin 1 mg/kg i.v., AmB 5 mg/kg i.p. or ITC 25 mg/kg p.o. were equivalent (P > 0.05). Aminocandin 5 mg/kg was superior to aminocandin 0.25 mg/kg (P < 0.0001) as well as all controls (P < 0.0001) in reducing mortality. Following infection with AF91, only aminocandin at 5 mg/kg and 1 mg/kg i.v. yielded 100% survival, which was superior to ITC, aminocandin 0.25 mg/kg and controls (all P < 0.0001). In the persistently neutropenic model with A1163, aminocandin, CAS and micafungin (2–10 mg/kg) were all effective at prolonging survival, with some impact on reducing culture burdens, even with alternate-day dosing (4 mg/kg). The only fungicidal regimen was aminocandin 5 mg/kg, which sterilised 40% and 50% of mice following infection with AF293 and AF91, respectively. Aminocandin at doses of ≥1 mg/kg is highly effective in reducing mortality and organ burden in disseminated infection caused by ITC-susceptible and -resistant A. fumigatus.     

Antimutagenic evaluation of vitamins B1, B6 and B12 in vitro and in vivo,with the Ames test

The aim of this work is to evaluate vitamins B antimutagenic effect against alkylatings methyl-N-nitro-N-nitrosoguanidine (MNNG), ethyl-N-nitro-N′- nitrosoguanidine (ENNG), frameshift mutagens 2-aminoanthracene (2AA) and 2-acetyl-amino-fluorene (2AF) and ROS-generating antibiotics norfloxacin (NOR) and nalidixic acid (NLX), using the in vitro Ames test. In vivo antimutagenesis studies were performed against urinary mutagens induced by NOR (70 mg/kg) or NLX (100 mg/kg) in CD1 mice.Vitamin B1 was antimutagenic against alkylatings MNNG (P < 0.05) or ENNG (P < 0.001). In fact as per the results observed during the current study, none of the vitamins reduced mutagenesis caused by frameshift mutagens. All of them reduced mutagenesis of NOR or NLX (P < 0.001). In vivo studies showed that vitamins B1 and B6 (10 or 100 mg/kg) reduced urinary mutagens from NOR (P < 0.001) or NLX (P < 0.02) either free or β-glucoronidase-conjugates. None of the studied samples were toxic for the employed antimutagenic system. Vitamin B12 (4 mg/kg) reduced urinary mutagens of NOR or NLX (P < 0.02).Vitamins B inhibited DNA mutations induced by ROS generated by NLX or NOR, both in vitro and in vivo. Vitamin B1is antimutagenic against mutations induced by the alkylating MNNG or ENNG. Based on the observations, employment of vitamins B in vivo can be a promising alternative to reduce genotoxic risk exposure to ROS.     

Analysis of changes in hepatic gene expression in a murine model of tolerance to acetaminophen hepatotoxicity (autoprotection)

Pretreatment of mice with a low hepatotoxic dose of acetaminophen (APAP) results in resistance to a subsequent, higher dose of APAP. This mouse model, termed APAP autoprotection was used here to identify differentially expressed genes and cellular pathways that could contribute to this development of resistance to hepatotoxicity. Male C57BL/6J mice were pretreated with APAP (400 mg/kg) and then challenged 48 h later with 600 mg APAP/kg. Livers were obtained 4 or 24 h later and total hepatic RNA was isolated and hybridized to Affymetrix Mouse Genome MU430_2 GeneChip. Statistically significant genes were determined and gene expression changes were also interrogated using the Causal Reasoning Engine (CRE). Extensive literature review narrowed our focus to methionine adenosyl transferase-1 alpha (MAT1A), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), flavin-containing monooxygenase 3 (Fmo3) and galectin-3 (Lgals3). Down-regulation of MAT1A could lead to decreases in S-adenosylmethionine (SAMe), which is known to protect against APAP toxicity. Nrf2 activation is expected to play a role in protective adaptation. Up-regulation of Lgals3, one of the genes supporting the Nrf2 hypothesis, can lead to suppression of apoptosis and reduced mitochondrial dysfunction. Fmo3 induction suggests the involvement of an enzyme not known to metabolize APAP in the development of tolerance to APAP toxicity. Subsequent quantitative RT-PCR and immunochemical analysis confirmed the differential expression of some of these genes in the APAP autoprotection model. In conclusion, our genomics strategy identified cellular pathways that might further explain the molecular basis for APAP autoprotection.     

Assessment of propofol,midazolam and ziprasidone,or the combinations for the prevention of acute cocaine toxicity in a mouse model

Study objectiveTo evaluate the effects of pretreatment, midazolam (M), propofol (P), ziprasidone (Z), and two combinations of [(midazolam plus propofol (MP); midazolam plus ziprasidone (MZ)] in mice models in the prevention of seizures, and death due to acute cocaine toxicity.Methods180 male CF-1 mice were randomized to 6 groups (30/group) in this experimental study. The animals were administered intraperitoneal injections of M (2 mg/kg), P (25 mg/kg), Z (4 mg/kg), MP (2 mg/kg and 25 mg/kg) and MZ (2 mg/kg and 4 mg/kg) or saline (S) as a pretreatment. 10 min later, the mice were administered intraperitoneal injections of 105 mg/kg cocaine. The groups were observed for cocaine-induced seizure and lethality.ResultsThe MP and MZ combinations showed the highest protective effect in terms of seizure and lethality relative to P and S (p < 0.001). M and Z were found effective compared to P and S (p < 0.001). There were no significant differences among MP and MZ, however there were significant differences between MP and Z in terms of lethality (p = 0.05). There were no significant differences among MP, MZ, M and Z groups in terms of seizure (p > 0.05). No death was observed in the MP combination group. Seizure rate was observed o be least in the MZ group with respect to the other groups.ConclusionAccording to our particular mouse model, this study suggests that MP and MZ combinations may be more effective than M or Z only for the prevention of cocaine-induced seizure and lethality. However, P alone does not prevent cocaine-induced seizure and lethality.     

Caffeic acid treatment alters the extracellular adenine nucleotide hydrolysis in platelets and lymphocytes of adult rats

This study evaluated the effects of caffeic acid on ectonucleotidase activities such as NTPDase (nucleoside triphosphate diphosphohydrolase), Ecto-NPP (nucleotide pyrophosphatase/phosphodiesterase), 5′-nucleotidase and adenosine deaminase (ADA) in platelets and lymphocytes of rats, as well as in the profile of platelet aggregation. Animals were divided into five groups: I (control); II (oil); III (caffeic acid 10 mg/kg); IV (caffeic acid 50 mg/kg); and V (caffeic acid 100 mg/kg). Animals were treated with caffeic acid diluted in oil for 30 days. In platelets, caffeic acid decreased the ATP hydrolysis and increased ADP hydrolysis in groups III, IV and V when compared to control (P < 0.05). The 5′-nucleotidase activity was decreased, while E-NPP and ADA activities were increased in platelets of rats of groups III, IV and V (P < 0.05). Caffeic acid reduced significantly the platelet aggregation in the animals of groups III, IV and V in relation to group I (P < 0.05). In lymphocytes, the NTPDase and ADA activities were increased in all groups treated with caffeic acid when compared to control (P < 0.05). These findings demonstrated that the enzymes were altered in tissues by caffeic acid and this compound decreased the platelet aggregation suggesting that caffeic acid should be considered a potentially therapeutic agent in disorders related to the purinergic system.     

Highly expressed protein kinase A inhibitor α and suppression of protein kinase A may potentiate acetaminophen-induced hepatotoxicity

Drug-induced hepatotoxicity is a serious adverse effect with high morbidity and mortality rates but substantial individual to individual variation is observed in its severity. Here we sought to discover factors determining the susceptibility to acetaminophen (APAP)-induced hepatotoxicity by comparing the global gene expression profile (27,342 genes) in pre-dose blood before APAP administration between susceptible and resistant animals (N = 5) grouped based on the severity of hepatotoxicity. Forty-one genes were expressed differently (>1.5 fold change and p < 0.05) between susceptible and resistant groups. Among them, protein kinase (cAMP-dependent) inhibitor alpha, Pkia, a member of protein kinase A (PKA) inhibitor family, was found to be most significantly and highly expressed in susceptible animals (∼3.5 fold with p < 0.01). To investigate the effects of PKA inhibition on APAP-induced hepatotoxicity, we pre-treated H-89, a potent and selective inhibitor of PKA, prior to APAP administration in vivo. As a result, H-89 pretreatment significantly potentiated APAP-induced hepatotoxicity as determined by the increased serum alanine transaminase. These results were further corroborated by the exacerbation of APAP-induced glutathione depletion, suppression of antioxidant enzyme system, superoxide dismutase 1 and glutathione peroxidase 1, and peroxynitrite generation in the liver following H-89 pretreatment, reflecting that PKA may be involved in the protection against, or attenuation of APAP-induced hepatotoxicity, and Pkia can be employed to screen individuals susceptible to APAP-induced hepatotoxicity.     

Research on choleretic effect of menthol,menthone, pluegone,isomenthone, and limonene in DanShu capsule

Danshu capsule (DSC) is a medicinal compound in traditional Chinese medicine (TCM). It is commonly used for the treatment of acute & chronic cholecystitis as well as choleithiasis. To study its choleretic effect, healthy rats were randomly divided into DSC high (DSCH, 900 mg/kg), medium (DSCM, 450 mg/kg), and low (DSCL, 225 mg/kg) group, Xiaoyan Lidan tablet (XYLDT, 750 mg/kg), and saline group. The bile was collected for 1 h after 20-minute stabilization as the base level, and at 1 h, 2 h, 3 h, and 4 h after drug administration, respectively. Bile volume, total cholesterol, and total bile acid were measured at each time point. The results revealed that DSC significantly stimulated bile secretion, decreased total cholesterol level and increased total bile acid level. Therefore, it had choleretic effects. To identify the active components contributing to its choleretic effects, five major constituents which are menthol (39.33 mg/kg), menthone (18.02 mg/kg), isomenthone (8.18 mg/kg), pluegone (3.31 mg/kg), and limonene (4.39 mg/kg) were tested on our rat model. The results showed that menthol and limonene could promote bile secretion when compared to DSC treatment (p > 0.05); Menthol, menthol and limonene could significantly decrease total cholesterol level (p < 0.05 or p < 0.01) as well as increase total bile acid level (p < 0.05 or p < 0.01); Isomenthone, as a isomer of menthone, existed slightly choleretic effects; Pluegone had no obvious role in bile acid efflux. These findings indicated that the choleretic effects of DSC may be attributed mainly to its three major constituents: menthol, menthone and limonene.     

Elucidation of protective efficacy of Pentahydroxy flavone isolated from Madhuca indica against arsenite-induced cardiomyopathy: Role of Nrf-2, PPAR-γ, c-fos and c-jun

BackgroundMadhuca indica J. F. Gmel. (Sapotaceae) is widely used ethnobotanically as anti-diabetic, antipyretic, hepatoprotective, anti-inflammatory and analgesic. It was shown to possess potent anti-apoptotic property.The aim of the studyTo evaluate the possible mechanism of action of isolated phytoconstituent from Madhuca indica Leaves methanolic extract (MI-ALC) on arsenic-induced cardiotoxicity in rats.Materials and methodsThe 3,5,7,3′,4′-Pentahydroxy flavone (QTN) was isolated and characterized by using HPTLC, ¹H NMR, and LC–MS from MI-ALC. QTN (5, 10 and 20 mg/kg, p.o.) was administered in arsenic intoxicated rats (5 mL/kg, p.o.) for 28 days and evaluated for various behavioral, biochemical, molecular and ultra-histological changes.ResultsTreatment with QTN (10 and 20 mg/kg, p.o.) significantly inhibited (p < 0.05) arsenic-induced electrocardiographic, hemodynamic and left ventricular function alterations. Elevated levels of cardiac markers (LDH, CK-MB, AST, ALT, and ALP), altered lipid metabolism (total cholesterol, triglyceride, LDL, HDL, and VLDL) was significantly restored (p < 0.05) by QTN. It also significantly inhibited (p < 0.05) altered cardiac oxido-nitrosative stress, Na-K-ATPase level and mitochondrial enzymes (I–IV) activity after arsenite administration. QTN significantly increased (p < 0.05) myocardial Nrf-2, PPAR-γ and significantly decreased (p < 0.05) myocardial c-fos and c-jun mRNA expressions. Flow cytometric analysis showed that treatment with QTN (10 and 20 mg/kg) significantly inhibited (p < 0.05) arsenite-induce ROS and apoptosis. It also reduced ultra-histological aberrations induced by sodium arsenite.ConclusionAdministration of 3,5,7,3′,4′- Pentahydroxy flavone (i.e. Quercetin (QTN)) isolated from MI-ALC showed significant protection against arsenic-induced oxido-nitrosative stress and myocardial injury via modulation of Nrf2, PPAR-γ, and apoptosis.     

Food–drug interactions: Effect of capsaicin on the pharmacokinetics of simvastatin and its active metabolite in rats

Capsaicin (trans-8-methy-N-vanilly-6-nonenamide, CAP), the main ingredient responsible for the hot pungent taste of chilli peppers. However, little is known about the metabolic interactions between CAP and clinically used drugs. This study attempted to investigate the effect of CAP on the pharmacokinetics of simvastatin (SV), a cytochrome P450 (CYP) 3A substrate and an important cholesterol-lowering agent. CAP (3, 8 or 25 mg/kg), ketoconazole, dexamethasone or 5% CMC-Na was given to rats for seven consecutive days and on the seventh day SV (80 mg/kg) was administered orally. The results showed that when a single dose of SV was administered to rats fed with CAP over one week, AUC_0→∞, C_max of SV and its acid metabolite was significantly decreased in comparison to the control treatment. Pretreatment of rats with CAP resulted in an decrease in the AUC_0–∞ of SV of about 67.06% (CAP 3 mg/kg, P < 0.05), 73.21% (CAP 8 mg/kg, P < 0.01) and 77.49% (CAP 25 mg/kg, P < 0.01) compared with the control group. The results demonstrate that chronic ingestion of high doses of CAP will decrease the bioavailability of SV to a significant extent in rats.     

Green tea extract can potentiate acetaminophen-induced hepatotoxicity in mice

Green tea extract (GTE) has been advocated as a hepatoprotective compound and a possible therapeutic agent for acetaminophen (APAP) overdose. This study was conducted to determine if GTE can provide protection against APAP-induced hepatotoxicity. Three different exposure scenarios were tested. The first involved administering APAP (150 mg/kg, orally) to mice followed 6 h later by GTE (500 or 1000 mg/kg). The other two involved administering GTE prior to the APAP dose. GTE (500 or 1000 mg/kg, orally) was administered 3 h prior to APAP (200 mg/kg, orally) or for three consecutive days (once-daily) followed by APAP (300 mg/kg) on the fourth day. Indices of hepatotoxicity were assessed 24 h after the APAP dose. GTE potentiated APAP-induced hepatotoxicity when administered after the APAP dose. GTE caused significant glutathione depletion and this effect likely contributed to the observed potentiation. In contrast, GTE provided protection against APAP-induced hepatotoxicity when administered prior to the APAP dose. GTE dramatically decreased APAP covalent binding to protein indicating that less reactive metabolite was available to cause hepatocellular injury. These results highlight the potential for drug-dietary supplement interactions and the importance of testing multiple exposure scenarios to adequately model different types of potential interactions.     

The application of 2-NBDG as a fluorescent tracer for assessing hepatic glucose production in mice during hyperinsulinemic euglycemic clamp

Methods of performing insulin clamps vary between laboratories. Here we present a protocol of insulin clamping in conscious mice, with the significant advantage of avoiding multiple surgical catheterizations and non-physiologic metabolism during the induction of anesthesia. Using this technique we also established a new method for measuring hepatic glucose production (HGP) using a fluorescent d-glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxyglucose (2-NBDG). To prove the reliability and feasibility of this method, whole-body insulin sensitivity was compared between conscious normal ICR mice and diabetic KK^Ay mice using the insulin clamp. Basal and clamp HGP was compared between normal C57 mice and diabetic db/db mice by using the modified clamp with 2-NBDG as a tracer. The glucose infusion rate (GIR), an index of insulin sensitivity, was significantly lower in KK^Ay mice than normal ICR mice (6.2±1.3 mg/kg/min vs. 31.3±2.9 mg/kg/min, P<0.001). The db/db mice also showed higher basal hepatic glucose production (25.8±2.2 mg/kg/min vs. 16.7±2.5 mg/kg/min, P<0.05), higher clamp HGP after insulin suppression (7.3±1.0 mg/kg/min vs. 0 mg/kg/min, P<0.001), and lower GIR (71.6±2.8 mg/kg/min vs. 15.2±1.6 mg/kg/min, P<0.001) than that obtained with normal C57 mice. In conclusion, this is the first report of the application of 2-NBDG, rather than isotopic tracers, for the determination of HGP in vivo.     

Oral administration of dehydroepiandrosterone-sulfate (DHEAS) increases in vitro lymphocyte function and improves in vivo response of pigs to immunization against keyhole limpet hemocyanin (KLH) and ovalbumin

The present study tested the hypothesis that the oral administration of DHEAS enhances the in vitro and the in vivo immune response of young pigs. Crossbred, female pigs (80 days of age; 49 ± 2 kg) were separated into two treatment groups (n = 4/treatment) receiving either 0 mg/kg (control) or 1 mg/kg DHEAS twice daily (DHEAS) for 5 weeks. On day 7 pigs were immunized against KLH and ovalbumin. Body weight increased weekly throughout the study but did not differ between treatment groups. While white blood cell counts increased in response to immunization but did not differ between treatments, the neutrophil:lymphocyte ratio was enhanced (P < 0.05) in DHEAS-supplemented pigs. Concanavalin A (ConA) induced an in vitro dose-dependent increase (P < 0.05) in lymphocyte proliferation, but treatment did not affect proliferation prior to immunization. However, lymphocytes isolated from DHEAS-supplemented pigs displayed a greater increase in proliferation following immunization relative to control pigs (P < 0.05). Dexamethasone (DEX) attenuated ConA-induced lymphocyte proliferation, with DHEAS-supplemented pigs retaining a greater proliferative response relative to control pigs (P < 0.05). Serum IgG concentrations and relative concentrations of antigen-specific IgG increased after immunization with maximum values attained at 21 and 28 days for control and DHEAS-supplemented pigs, respectively. The DHEAS-supplemented pigs had greater (P < 0.05) concentrations of IgG and relative concentrations of antigen-specific IgG compared to control pigs. Collectively these data suggest DHEAS supplementation increases the responsiveness of young pigs to antigenic challenge, and may be beneficial for improving their immune function.     

Safety evaluation of daidzein in laying hens: Part I. Effects on laying performance,clinical blood parameters,and organs development

Daidzein, an estrogen-like product, becomes increasingly popular as a dietary supplement, particularly for postpeak-estrus animals seeking a safe natural alternative to play a role of estrogen. However, there is little available safety data of it for raisers and consumers. A subchronic laying hen safety study was conducted to examine if the high-dose daidzein could affect the safety of hens selves, including laying performance, clinical blood parameters and organs development. Seven hundred and sixty-eight 56-week-old Hyline Brown were randomly assigned to 4 groups with 8 replicates of 24 birds each and 3 weeks later fed diets supplemented with 0, 10, 50 and 100 mg of daidzein/kg for 12 weeks. The mortality was significantly decreased (P < 0.05). No treatment related adverse clinical signs were observed. Mean egg production, egg mass and feed conversion of whole experiment period was significantly influenced by dietary daidzein supplement (P < 0.05), showing significant quadratic response to increasing dietary daidzein supplement (P = 0.029, P = 0.003 and P = 0.019, respectively). There was no statistically significant changes in haematology (P > 0.05). In clinical chemistry parameters, total protein, total cholesterol, calcium and phosphorus were significantly affected by dietary daidzein supplement (P < 0.05). The no observed adverse effect level (NOAEL) is considered to be 50 mg/kg.     

Safety evaluation of a triazine compound nitromezuril by assessing bacterial reverse mutation,sperm abnormalities,micronucleus and chromosomal aberration

Nitromezuril (NZL) is a novel triazine compound that exhibits remarkable anticoccidial activity. However, mutagenicity and genotoxicity of NZL have not been evaluated to date. This study evaluated the potential risks of NZL by testing for bacterial reverse mutation (Ames), mouse sperm abnormality (SA), bone marrow micronucleus (MN) and chromosomal aberration (CA). Mice were orally administered with NZL at 385, 192 and 96 mg/kg, corresponding to 0.5×, 0.25× and 0.125× the LD₅₀ of NZL, respectively. No significant increases in SA and CA were found in mice treated with NZL for 5 d and 3 d, respectively (P > 0.05). NZL at 96–385 mg/kg did not have significant influence on micronucleated polychromatic erythrocyte counts (P > 0.05). These results suggest that NZL is not genotoxic. However, Ames test results were positive both with and without the S9 system for Salmonella typhimurium TA98 and TA100, suggesting that NZL may be mutagenic. The mutagenic effects of NZL were different in in vitro and in vivo assays. Further studies should be conducted to confirm the safety of using and developing NZL as a novel anticoccidial drug.     

Ginsenoside Rg5 improves cognitive dysfunction and beta-amyloid deposition in STZ-induced memory impaired rats via attenuating neuroinflammatory responses

Neuroinflammatory responses play a crucial role in the pathogenesis of Alzheimer's disease (AD). Ginsenoside Rg5 (Rg5), an abundant natural compound in Panax ginseng, has been found to be beneficial in treating AD. In the present study, we demonstrated that Rg5 improved cognitive dysfunction and attenuated neuroinflammatory responses in streptozotocin (STZ)-induced memory impaired rats. Cognitive deficits were ameliorated with Rg5 (5, 10 and 20 mg/kg) treatment in a dose-dependent manner together with decreased levels of inflammatory cytokines TNF-α and IL-1β (P < 0.05) in brains of STZ rats. Acetylcholinesterase (AChE) activity was also significantly reduced by Rg5 whereas choline acetyltransferase (ChAT) activity was remarkably increased in the cortex and hippocampus of STZ-induced AD rats (P < 0.05). In addition, Congo red and immunohistochemistry staining results showed that Rg5 alleviated Aβ deposition but enhanced the expressions of insulin-like growth factors 1 (IGF-1) and brain derived neurophic factor (BDNF) in the hippocampus and cerebral cortex (P < 0.05). Western blot analysis also demonstrated that Rg5 increased remarkably BDNF and IGF-1 expressions whereas decreased significantly Aβ deposits (P < 0.05). Furthermore, it was observed that the expressions of COX-2 and iNOS were significantly up-regulated in STZ-induced AD rats and down-regulated strongly (P < 0.05) by Rg5 compared with control rats. These data demonstrated that STZ-induced learning and memory impairments in rats could be improved by Rg5, which was associated with attenuating neuroinflammatory responses. Our findings suggested that Rg5 could be a beneficial agent for the treatment of AD.