摘要：
lambda-Carrageenan (Carr), a seaweed polysaccharide, is used as a proinflammatory agent in research. Betulinic acid (BA), a naturally occurring pentacyclic triterpenoid, exerts immunomodulatory, antioxidant, anti-inflammatory, anti-tumor, anti-malarial and anti-HIV effects. The aim of this study was to investigate whether BA exerts anti-inflammatory effect against Carr-induced paw edema in mice, and how BA could mediate the expression of inflammation-associated MAPK-COX-2-PGE(2) signal pathway. BA pretreatment significantly reduced the in-flammatory response to Carr-induced paw edema, especially at 4 h after injection. BA reduced the serum levels of pro-inflammatory cytokines, such as IL-1 alpha, IL-1 beta, IL-5, IL-6, GM-CSF, KC, MCP-1 and PGE(2) in Carr-treated mice, and increased those of anti-inflammatory cytokines, such as IL-12. It also increased SOD, CAT and GSH-Px activities, and GSH content, and reduced MDA content in the liver of Carr-treated mice. Besides, BA reduced neutrophil infiltration in the basal and subcutaneous layers of the paw of Carr-treated mice, decreased the expression of COX-2 protein, and reduced the phosphorylation of JNK, p38 and ERK1/2. These results indicated that the protective effect of BA on Carr-induced paw edema might be due to its alleviation of inflammatory response and inhibition of oxidative stress, possibly by inhibiting MAPK-COX-2-PGE(2) signaling pathway activation.
作者机构：
[Wu, Jing; Wang, Naidong; Wang, ND; Tian, Yanan; Zhou, Yu; Yi, Jine; Yuan, Zhihang] Hunan Agr Univ, Coll Vet Med, Changsha 410128, Hunan, Peoples R China.;[Wu, Jing; Yuan, Zhihang] Hunan Agr Univ, Hunan Collaborat Innovat Utilizat Bot Funct Ingre, Changsha 410128, Hunan, Peoples R China.;[Wu, Jing; Yuan, Zhihang] Hunan Agr Univ, Hunan Engn Res Ctr Vet Drug, Changsha 410128, Hunan, Peoples R China.;[Chen, Jingshu; Tian, Yanan] Texas A&M Univ, Coll Vet Med, Dept Vet Physiol & Pharmacol, College Stn, TX 77843 USA.
通讯机构：
[Wang, ND; Tian, YA] H;[Tian, Yanan] T;Hunan Agr Univ, Coll Vet Med, Changsha 410128, Hunan, Peoples R China.;Texas A&M Univ, Coll Vet Med, Dept Vet Physiol & Pharmacol, College Stn, TX 77843 USA.
关键词：
T-2 toxin;toxicity;autophagy;apoptosis
摘要：
T-2 toxin is a mycotoxin generated by Fusarium species which has been shown to be highly toxic to human and animals. T-2 toxin induces apoptosis in various tissues/organs. Apoptosis and autophagy are two closely interconnected processes, which are important for maintaining physiological homeostasis as well as pathogenesis. Here, for the first time, we demonstrated that T-2 toxins induce autophagy in human liver cells (L02). We demonstrated that T-2 toxin induce acidic vesicular organelles formation, concomitant with the alterations in p62/SQSTM1 and LC3-phosphatidylethanolamine conjugate (LC3-II) and the enhancement of the autophagic flux. Using mRFP-GFP-LC3 by lentiviral transduction, we showed T-2 toxin-mediated lysosomal fusion and the formation of autophagosomes in L02 cells. The formation of autophagosomes was further confirmed by transmission electron microcopy. While T-2 toxin induced both autophagy and apoptosis, autophagy appears to be a leading event in the response to T-2 toxin treatment, reflecting its protective role in cells against cellular damage. Activating autophagy by rapamycin (RAPA) inhibited apoptosis, while suppressing autophagy by chloroquine greatly enhanced the T-2 toxin-induced apoptosis, suggesting the crosstalk between autophagy and apoptosis. Taken together, these results indicate that autophagy plays a role in protecting cells from T-2 toxin-induced apoptosis suggesting that autophagy may be manipulated for the alleviation of toxic responses induced by T-2 toxin.
摘要：
Phenethyl isothiocyanate (PEITC) is one of the glucosinolates (GLs) present in cruciferous vegetables. Although there are many reports of livestock and poultry poisoning caused by plants containing GLs, the actual dosage that causes poisoning and the characteristics of GLs and their metabolites are unclear. Herein, we investigated the inhibitory effects of PEITC on IPEC-J2 cells and examined the mechanisms of PEITC-induced apoptosis via the mitochondrial pathway. Cell viability was determined by the MTT assay, and the levels of reactive oxygen species, mitochondrial membrane potential (Psi), intracellular Ca(2+) concentration, and cell apoptosis were detected by flow cytometry. IPEC-J2 cells were collected to assess the activities of superoxide dismutase, catalase, and glutathione peroxidase, as well as the contents of glutathione, malondialdehyde, H2O2, ATP, and lactate dehydrogenase, using biochemical methods. The levels of cytochrome c, Bax, Bcl-2, caspase-3, caspase-9, poly (ADP-ribose) polymerase (PARP)-1, p53, CDC25C, and cyclin A2 were analyzed by western blotting. We found that PEITC effectively inhibited the growth of IPEC-J2 cells, causing apoptosis. PEITC suppressed the level of mitochondrial membrane potential; released cytochrome c from the mitochondria to the cytoplasm; reduced ATP levels; inhibited Bcl-2 expression; increased Bax expression; and activated caspase-9, caspase-3, and PARP-1, leading to apoptosis. PEITC also induced G2/M and S phase arrest by affecting cell cycle-associated proteins such as p53, CDC25C, and cyclin A2. We conclude that PEITC causes oxidative stress, cell cycle arrest, and apoptosis in IPEC-J2 cells via a mitochondrial-dependent Bax/Bcl-2 pathway.
摘要：
Gamma-oryzanol (Orz), a mixture of ferulic acid esters of plant sterols and triterpene alcohols, has been proven to possess multiple activities. The purpose of this study was to explore the hepatoprotective effects and potential mechanisms of Orz against ethanol-induced liver injury in mice. Orz pretreatment significantly reduced the serum levels of ALP, ALT, AST and CYP2E1, and increased the TP and GLB levels in the ethanol-challenged mice. Orz increased the activities of CAT, SOD, GSH-PX and the GSH content in the liver, while decreased hepatic steatosis in ethanol-induced liver injure. Furthermore, Orz significantly decreased the protein expression of ASK1, JNK, P38, active-caspase-9 and active-caspase-3, and the protein ratio of Bax/Bcl-2 in livers of ethanol-challenged mice. These results suggest that Orz provides protection against ethanol-induced liver injury which might be due to its alleviation of oxidative stress and inhibition of apoptosis, possibly inhibiting MAPK signaling pathways mediated mitochondrial signaling pathway activation.
摘要：
T-2 toxin is one of the most toxic type A trichothecene mycotoxins in nature, and it exhibits reproductive toxicity. Betulinic acid (BA) is a natural pentacyclic triterpene compound found in species of Betula, and it has been reported to have antioxidant activity. The aim of the present study was to investigate the protective effect of BA on T-2-toxin-induced testicular injury in mice and explore its molecular mechanism. Sixty adult male mice were randomly divided into groups. The mice were pretreated orally with BA (0.25, 0.5, and 1.0 mg/kg) daily for 14 days, and the T-2 toxin (4 mg/kg body weight) was administered via intraperitoneal injection to induce oxidative stress after the last administration of BA. BA pretreatment significantly increased the secreted levels of testosterone and sperm motility. Moreover, BA pretreatment significantly increased the total antioxidant capacity (T-AOC), the activity of SOD and CAT, and the content of GSH, and it reduced the content of MDA. Furthermore, BA relieved testicular injury and reduced the number of apoptotic cells, and it significantly decreased the protein expression of Janus kinase 2 (JAK2), signal transducers and activators of transcription 3 (STAT3), caspsae-3, and Bcl-2-associated X protein (Bax). BA also increased the expression of B-cell lymphoma-2 (Bcl-2). We suggest that BA reduced the oxidative damage induced by T-2 toxin, and that these protective effects may be partially mediated by the JAK2/STAT3 signaling pathway.
摘要：
Dexamethasone (Dex), a potent anti-inflammatory/immunosuppressive agent, has been shown to induce oxidative stress. Betulinic acid (BA) is a pentacyclic lupane triterpene with a potent antioxidant activity. The aim of this study was to investigate the ameliorative effect and underlying mechanisms of BA on Dex-induced oxidative damage. Mice were pretreated with BA orally (0, 0.25, 0.5, and 1.0 mg/kg) daily for 14 days, and then a single dose of Dex (25 mg/kg body weight) was administered intraperitoneally 8 h after the last administration of BA to induce oxidative stress. BA pretreatment significantly alleviated Dex-induced changes of blood biochemical indices, increased the total antioxidant capacity (T-AOC), the activity of superoxide dismutase (SOD), and the ability of inhibiting hydroxyl radical (AIHR), reduced the level of malondialdehyde (MDA) in serum. Moreover, BA pretreatment enhanced the T-AOC, AIHR and the activity of peroxidase (POD) in liver, spleen and thymus. Concomitant with these biochemical parameters, BA pretreatment significantly reduced gene and protein expressions of apoptosis signal-regulating kinase 1 (ASK1), c-Jun N-terminal kinase (JNK) and P38 mitogen-activated protein kinase (P38 MAPK) in the lymphatic organs of Dex-treated mice. BA was found to effectively attenuate Dex-induced oxidative damage. These protective effects may be mediated in part through the JNK-P38 MAPK signaling transduction pathway and BA may be a potential therapeutic agent due to its anti-oxidative properties.
摘要：
Although mTOR (the mammalian target of rapamycin) can regulate intracellular free Ca2+concentration in normal cultured podocytes, it remains elusive as to how mTORC2/AKT-mediated Ca2+participates in the process of T-2 toxin-induced apoptosis. The potential signaling responsible for intracellular Ca2+ concentration changes was investigated using immunoblot assays in an in vitro model of TM3 cell injury induced by T-2 toxin. Changes in Ca2+ were assessed using the Ca2+-sensitive fluorescent indictor dye Fura 2-AM. The cytotoxicity of TM3 cells was assessed with an MTT bioassay, and apoptosis was measured using Annexin V-FITC staining. Following T-2 toxin treatment, the growth of cells, phospho-mTORSer2481, phospho-mTORSer2448, and phospho-AktSer473 were significantly decreased in a time-dependent manner, whereas Ca2+ and apoptosis were increased. T-2 toxin-induced apoptosis was prevented by BAPTA-AM (a Ca2+chelator) and MHY1485 (an mTOR activator), and the application of mTOR activator MHY1485 also prevented the increase of intracellular free Ca2+concentration in TM3 cells. Our results strongly suggest that T-2 toxin exposure induces apoptosis in TM3 cells by inhibiting mTORC2/AKT to promote Ca2+ production.
