In Vitro Protective Efficacy of Clostridium butyricum Against Fish Pathogen Infections

Most pathogens in intestine are opportunist, called “opportunistic pathogens” that usually do not cause disease in a healthy host. Only when the host’s resistance is lowered or the intestinal microecological balance is destroyed, the opportunistic pathogens are capable of causing disease. Here, two opportunistic pathogens, Salmonella enteritidis and Vibrio parahaemolyticus were chosen to test the possible antagonistic effect of the probiotic agent Clostridium butyricum on these pathogens infections in vitro using fish intestinal epithelial cells (FIECs). The C. butyricum and its spent culture supernatants exhibited significant inhibitory activity on S. enteritidis and V. parahaemolyticus growth and adherence to FIECs. The C. butyricum also showed significant inhibitory effects on S. enteritidis and V. parahaemolyticus induced apoptosis, which may due to its growth and adhesion inhibitory effects. These results indicated that the probiotic bacterium C. butyricum has preventive and therapeutic effects on S. enteritidis and V. parahaemolyticus infections in fish.     

Protective Effects of Zonisamide Against Rotenone-Induced Neurotoxicity

Zonisamide (ZNS), an antiepileptic drug having beneficial effects also against Parkinson’s disease symptoms, has proven to display an antioxidant effects in different experimental models. In the present study, the effects of ZNS on rotenone-induced cell injury were investigated in human neuroblastoma SH-SY5Y cells differentiated towards a neuronal phenotype. Cell cultures were exposed for 24 h to 500 nM rotenone with or without pre-treatment with 10–100 μM ZNS. Then, the following parameters were analyzed: (a) cell viability; (b) intracellular reactive oxygen species production; (c) mitochondrial transmembrane potential; (d) cell necrosis and apoptosis; (e) caspase-3 activity. ZNS dose-dependently suppressed rotenone-induced cell damage through a decrease in intracellular ROS production, and restoring mitochondrial membrane potential. Similarly to ZNS effects, the treatment with N-acetyl-cysteine (100 μM) displayed significant protective effects against rotenone-induced ROS production and Δψ_m at 4 and 12 h respectively, reaching the maximal extent at 24 h. Additionally, ZNS displayed antiapoptotic effects, as demonstrated by flow cytometric analysis of annexin V/propidium iodide double staining, and significant attenuated rotenone-increased caspase 3 activity. On the whole, these findings suggest that ZNS preserves mitochondrial functions and counteracts apoptotic signalling mechanisms mainly by an antioxidant action. Thus, ZNS might have beneficial effect against neuronal cell degeneration in different experimental models involving mitochondrial dysfunction.     

茶多酚保护脑神经防止帕金森病损伤作用及其分子机理

详细介绍了茶多酚保护脑神经防止PD损伤作用及其分子机理.家族遗传虽然是帕金森病(PD)的重要因素,但主要与环境因素有关(大约70%),其中氧化应激在致病机理中发挥着重要作用.茶多酚的抗氧化作用和及饮后可以进入血液甚至穿越血脑屏障为其保护脑神经防止PD提供了重要条件.在细胞水平,选择6-OHDA诱导的PC12和SH-SYSY细胞作为细胞模型.结果表明,茶多酚预处理可明显减少细胞的凋亡率,防止线粒体膜电位下降,降低细胞内活性氧和钙离子累积.茶多酚还可以抑制6-OHDA诱导NO升高和nNOS与iNOS过量表达,降低细胞内蛋白质结合硝基酪氨酸水平.在动物水平,利用6-OHDA建立PD大鼠模型,探讨茶多酚对其保护作用机制.结果发现,茶多酚可以浓度和时间依赖性减轻6-OHDA诱导产生的旋转行为,降低中脑和纹状体中ROS和NO含量、脂质过氧化程度、硝酸盐/亚硝酸盐含量、蛋白质结合硝基酪氨酸浓度,同时降低nNOS和iNOS表达水平.茶多酚预处理可增加黑质致密部存活神经元,减少凋亡细胞.上述实验结果证明,口服茶多酚可以有效保护脑组织免于6-OHDA损伤引起的神经细胞死亡,其保护作用可能是通过ROS和NO的途径减少过氧亚硝基的生成实现的.     

脓青素对光抑制条件下菠菜叶绿体的保护作用

在有氧条件下,脓青素可以缓解强光对菠菜叶绿体电子传递的抑制作用。加入解联剂尼日利亚菌素消除跨膜质子梯度会加剧叶绿体的光抑制,但脓青素的保护作用并不消失。脓青素对光系统Ⅰ与光系统Ⅱ均表现出保护作用,但对ＰＳⅡ的保护在光抑制初期较明显;在厌氧条件下,脓青素加剧叶绿体的光抑制,引起ＤＣＩＰ光还原与水到ｐ－ＢＱ电子传递活力的降低。推测脓青素可能通过促进细胞色素ｂ５５９介导的ＰＳⅡ循环电子传递,减轻了叶绿体的光抑制。     

间充质干细胞移植对放射性肠损伤修复作用的实验研究

探讨了人间充质干细胞(mesenchymal stem cells,MSCs)移植对NOD/SCID小鼠放射性肠损伤的修复作用．将雄性NOD/SCID小鼠随机分为3组,每组6只,即A组为空白对照组,B组为模型组,C组为治疗组．B组和C组小鼠全腹接受5 Gy ⁶⁰Co γ射线单次照射,剂量率为100 cGy/min．照射后B组小鼠经尾静脉注射生理盐水,C组小鼠移植MSCs．于移植后第15天取小鼠空肠标本,通过免疫荧光方法检测MSCs在受损肠道的定植和分化情况．结果表明,治疗组小鼠的生存状况明显好于模型组小鼠,病理切片显示小肠黏膜得到修复,免疫荧光结果显示MSCs可定植于辐射损伤的肠道,并表达波形蛋白(vimentin)和α-SMA．MSCs移植入肠损伤的小鼠体内后可在受损肠道定植,并向间质细胞分化,参与辐射损伤的修复.     

Protective Effects of Antioxidants Against Cadmium-induced Oxidative Damage in Rat Testes

The protective effects of melatonin, vitamin E, and selenium alone or in combination were tested against cadmium-induced oxidative damage in rat testes. A total of 60 male rats were equally divided into five study groups, one of which acted as control receiving subcutaneous injections of physiological saline. The remaining four groups were treated with subcutaneous injections of cadmium chloride at a dose of 1 mg/kg weight. The first study group received no treatment. The second group was treated with a combination of 60 mg/kg vitamin E and 1 mg/kg sodium selenite. Group 3 was treated with 10 mg/kg melatonin, and the fourth group received a combination of vitamin E, sodium selenite, and melatonin at the doses mentioned above. After 1 month, the animals were killed, and the testes were excised for histological inspection and determination of tissue malondialdehyde and the activity of superoxide dismutase. The animals receiving no treatment showed significantly higher malondialdehyde levels and reduced activity of the enzyme (p < 0.05). Treatment with antioxidants resulted in a significant reduction in malondialdehyde when compared to the nontreated animals (p < 0.05) and an increase in the superoxide dismutase activity that was almost the same as the controls. The combination of melatonin, vitamin E, and selenium appears to have the more profound effect against cadmium-induced testicular injury.     

Protective Effects of Piperine Against Corticosterone-Induced Neurotoxicity in PC12 Cells

Hyperactivation of the hypothalamic–pituitary–adrenal axis and the associated hippocampal atrophy were observed in patients with depression, which could be ameliorated by the treatment with antidepressants. Therefore, neuroprotection has been proposed to be one of the acting mechanisms of antidepressant. Our previous studies have showed that treating mice with piperine produced antidepressant-like effect in animal models of behavioral despair. This study aimed to examine the protective effect of piperine treatment on corticosterone-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. The results showed that piperine co-treatment revealed a differential effect on the cytotoxicity of corticosterone and had its maximum inhibitory effect at 1 μM. Piperine (1 μM) co-treatment also significantly decreased intracellular reactive oxygen species level, and enhanced superoxide dismutase activity and total glutathione level in corticosterone-treated PC12 cells. In addition, piperine (1 μM) co-treatment was found to reverse the decreased brain-derived neurotrophic factor (BDNF) mRNA level caused by corticosterone in PC12 cells. The results suggest that piperine exerts a neuroprotective effect on corticosterone-induced neurotoxicity in PC12 cells, at least in part, via the inhibition of oxidative stress and the upregulation of BDNF mRNA expression. This neuroprotective effect may be one of the acting mechanisms accounts for the in vivo antidepressant activity of piperine.     

铜纳米颗粒对缺血性卒中后神经血管单元的保护作用

目的:研究铜纳米颗粒(copper nanoparticle,Cu-nps)对缺血性卒中后神经血管单元(neurovascular units,NVU)的保护作用。方法:采用加热搅拌法合成Cu-nps。体内建立大鼠短暂大脑中动脉阻塞/再灌注模型(transient middle cerebral artery occlusion / reperfusion,tMCAO),实验分为正常组(sham)、模型组(tMCAO)、给药组(Cu-nps),检测各组脑梗死面积、神经凋亡情况、血脑屏障(blood-brain barrier,BBB)完整性以及相关蛋白表达。结果:制备出的Cu-nps以Cu²⁺、80 nm左右的粒径均匀存在,具有良好的生物相容性。Cu-nps靶向脑缺血部位受损神经元,提高神经元细胞活力,降低活性氧,减少神经元凋亡和脑梗死面积,降低伊文思蓝染料渗漏量和炎症因子表达。结论:Cu-nps可以减少氧化应激,保护BBB完整性,降低神经胶质细胞活化,保护NVU功能,从而降低脑缺血再灌注损伤。     

Protective Effects of YC-1 Against Glutamate Induced PC12 Cell Apoptosis

Glutamate, one of the major neurotransmitters in the central nervous system, is released into the synaptic spaces and bound to the glutamate receptors which facilitate normal synaptic transmission, synaptic plasticity, and brain development. Past studies have shown that glutamate with high concentration is a potent neurotoxin capable of destroying neurons through many signal pathways. In this research, our main purpose was to determine whether the specific soluble guanylyl cyclase activator YC-1 (3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole) had effect on glutamate-induced apoptosis in cultured PC12 cells. The differentiated PC12 cells impaired by glutamate were used as the cell model of excitability, and were exposed to YC-1 or/and ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) with gradient concentrations for 24 h. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl) assay was used to detect the cellular viability. Radioimmunoassay (RIA) was used to detect the cGMP (cyclic guanosine monophosphate) concentrations in PC12 cells. Hoechst 33258 staining and flow cytometric analysis were used to detect the cell apoptosis. The cellular viability was decreased and the apoptotic rate was increased when PC12 cells were treated with glutamate. Cells treated with YC-1 or/and ODQ showed no significant differences in the cell viability and intracellular cGMP levels compared with those of control group. The specific soluble guanylyl cyclase (sGC) inhibitor ODQ showed an inhibitory effect on cGMP level and aggravated the apoptosis of PC12 cells induced by glutamate. YC-1 elevated cGMP level thus decreased PC12 cell apoptosis induced by glutamate, but this effect could be reversed by ODQ. These results revealed that YC-1 might attenuate glutamate-induced PC12 cell apoptosis via a sGC–cGMP involved pathway.     

The Protective Effects of Inosine Against Chemical Hypoxia on Cultured Rat Oligodendrocytes

Inosine is a purine nucleoside and is considered protective to neural cells including neurons and astrocytes against hypoxic injury. However, whether oligodendrocytes (OLs) could also be protected from hypoxia by inosine is not known. Here we investigated the effects of inosine on primarily cultured rat OLs injured by rotenone-mediated chemical hypoxia, and the mechanisms of the effects using ATP assay, MTT assay, PI-Hoechst staining, TUNEL, and immunocytochemistry. Results showed that rotenone exposure for 24 h caused cell death and impaired viability in both immature and mature OLs, while pretreatment of 10 mM inosine 30 min before rotenone administration significantly reduced cell death and improved the viability of OLs. The same concentration of inosine given 120 min after rotenone exposure also improved viability of injured mature OLs. Immunocytochemistry for nitrotyrosine and cellular ATP content examination indicated that inosine may protect OLs by providing ATP and scavenging peroxynitrite for cells. In addition, immature OLs were more susceptible to hypoxia than mature OLs; and at the similar degree of injury, inosine protected immature and mature OLs differently. Quantitative real-time PCR revealed that expression of adenosine receptors was different between these two stages of OLs. These data suggest that inosine protect OLs from hypoxic injury as an antioxidant and ATP provider, and the protective effects of inosine on OLs vary with cell differentiation, possibly due to the adenosine receptors expression profile. As OLs form myelin in the central nervous system, inosine could be used as a promising drug to treat demyelination-involved disorders.     

Induction of Protective Immunity Against Cryptococcosis

Cryptococcus neoformans, the predominant etiological agent of cryptococcosis, is an encapsulated fungal pathogen that can cause life-threatening infections of the central nervous system in immune compromised individuals resulting in high morbidity and mortality. Consequently, several studies have endeavored to understand those mechanisms that mediate resistance and susceptibility to Cryptococcus infection. In this review, we will examine the contributions of various components of the innate and adaptive immune response toward protection against cryptococcosis. We will focus our discussion on studies presented at the 8th International Conference on Cryptococcus and Cryptococcosis (ICCC). Remarkable progress has been made toward our understanding of host immunity and susceptibility to cryptococcal infection and the potential for vaccine development.     

Toxic Effect of Cysteine Against Salmonella typhimurium

Cysteine was shown to be toxic to Salmonella typhimurium. The mechanism of this toxicity may be due, at least in part, to cysteine's ability to cause deoxyribonucleic acid strand scissions.     

山核桃叶总黄酮抑制TBBPA诱导斑马鱼胚胎发育毒性的研究

四溴双酚A(tetrabromobisphenol A,TBBPA)是新型高关注度污染物之一,对鱼类具有强毒性。山核桃叶中的黄酮类化合物具有抗氧化和抗细胞凋亡等作用。通过硅胶柱洗脱、薄层色谱(TLC)检测对山核桃叶进行提取和纯化,得到黄酮类化合物产物B;设置4个实验组(空白对照,0.5 mg/L TBBPA,1.0 mg/L产物B,0.5 mg/L TBBPA和1.0 mg/L产物B),记录斑马鱼胚胎发育过程中的形态学指标;同时,检测不同处理组中活性氧(reactive oxygen species,ROS)水平和凋亡相关基因的表达情况。结果发现,山核桃叶提取的总黄酮产物B中包含50%的查尔酮、27%的黄酮或者黄酮醇、18%的二氢黄酮或者二氢黄酮醇、5%的异黄酮等22种黄酮类化合物;富含黄酮类化合物的产物B对TBBPA诱导斑马鱼胚胎的卵凝结率、畸形率及32 h血流障碍等指标具有显著降低作用;可显著抑制TBBPA诱导的ROS水平升高;对TBBPA诱导的凋亡基因p53上调和Bcl-2下调均有显著改善作用。实验结果表明山核桃叶总黄酮通过降低ROS水平,抑制凋亡基因的异常表达,发挥抗氧化和抑制凋亡作用。实验结果有助于了解山核桃叶有效成分总黄酮对TBBPA诱导的斑马鱼胚胎毒性的保护作用,为水生态系统和人体健康危害的防治提供新思路。     

Protective Effects of Pyridoxal Phosphate Against Glucose Deprivation-Induced Damage in Cultured Hippocampal Neurons

Abstract: When hippocampal cultures were deprived of glucose, massive release of lactate dehydrogenase (LDH), an indicator of neuronal death, occurred via NMDA receptor activation. Addition of pyridoxal phosphate (PLP; 1 and 10 µ M ) inhibited this LDH release in a concentration-dependent manner. Prior exposure to PLP evoked more potent inhibitory effects on LDH release compared with those treated at the onset of glucose deprivation. Furthermore, PLP inhibited the reduction of intracellular content of pyruvate induced by glucose deprivation, which was accompanied by the reversal of intracellular ATP depletion. A noteworthy elevation of extracellular glutamate in response to glucose deprivation was completely reversed by addition of PLP. Aminooxyacetic acid, a potent inhibitor of PLP-dependent enzymes, antagonized the effects of PLP on LDH release, pyruvate production, and ATP formation. These results suggest that PLP protects neurons from glucose deprivation-induced damage by enhancing the formation of energy-yielding products and relieving extracellular load of glutamate. The observed phenomena further indicate that PLP might be used prophylactically against neuronal death induced by metabolic disorders.