即早基因在N-甲基-N-亚硝脲诱导SD大鼠视网膜变性中的表达

目的研究N-甲基-N-亚硝脲(N-m ethyl-N-n itrosourea,MNU)对SD大鼠视网膜毒性的分子机制。方法于♀SD大鼠出生后50 d,一次腹腔注射(ip)MNU 60 mg.kg-1。在MNU处理不同时间后,处死大鼠,取眼球。进行组织学检查;TUNEL试剂盒检测光感受器细胞凋亡;RT-PCR法检测基因c-jun和c-fos的表达。结果MNU作用24 h后,视网膜光感受器外节部定向紊乱;7 d后,外颗粒层和光感受层几乎完全消失。MNU作用12 h后,光感受器细胞开始发生凋亡,24 h达高峰。MNU可时间依赖性地上调即早基因的表达。结论MNU对视网膜的毒性作用是通过增加基因c-jun和c-fos的表达,从而诱导光感受器细胞发生凋亡。     

Role of hippocampus in alcohol-induced memory impairment: implications from behavioral and immediate early gene studies

 Acute alcohol intoxication disrupts memory acquisition in humans and laboratory animals. This review summarizes recent behavioral and immediate early gene expression studies addressing the mechanisms of this phenomenon. Most behavioral investigations agree that the amnestic effect of alcohol is due to its preferential detrimental effect on hippocampus-dependent than on hippocampus-independent forms of learning. However, some hippocampal lesion studies contradict these results. Learning in behavioral paradigms is accompanied by induction of c-fos and other immediate early genes in many brain regions of the animal. In contrast, studies on alcohol-mediated changes in expression of this gene confirm selective hippocampal suppression of basal and experience-induced expression of c-fos after acute and repeated administration of alcohol. This hippocampal suppression is in marked contrast with alcohol-mediated induction of c-fos expression in other brain areas. However, the selective suppression of hippocampal gene expression and memory by alcohol is most likely mediated by a number of interacting neurotransmitter systems. Thus, effects of lower doses of alcohol (0.5 g/kg or lower in rats) seem to be preferentially mediated through GABAergic systems. At intermediate doses (0.75–2 g/kg), several other neurotransmitter systems are affected besides GABA. Higher doses lead to none-specific effects, probably involving even more neurotransmitter systems. Elucidation of these neurotransmitter systems will be highly important for developing rational approaches for correction of alcohol-related cognitive disorders. Received: 2 December 1997 / Final version: 22 January 1998     

Chronic methylphenidate induces increased quinone production and subsequent depletion of the antioxidant glutathione in the striatum

BackgroundMethylphenidate (Ritalin®) is a psychostimulant used chronically to treat attention deficit hyperactivity disorder. Methylphenidate acts by preventing the reuptake of dopamine and norepinephrine, resulting in an increase in these neurotransmitters in the synaptic cleft. Excess dopamine can be autoxidized to a quinone that may lead to oxidative stress. The antioxidant, glutathione helps to protect the cell against quinones via conjugation reactions; however, depletion of glutathione may result from excess quinone formation. Chronic exposure to methylphenidate appears to sensitize dopaminergic neurons to the Parkinsonian toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We hypothesized that oxidative stress caused by the autooxidation of the excess dopamine renders dopaminergic neurons within the nigrostriatal pathway to be more sensitive to MPTP.MethodsTo test this hypothesis, male mice received chronic low or high doses of MPH and were exposed to saline or MPTP following a 1-week washout. Quinone formation in the striatum was examined via dot blot, and striatal GSH was quantified using a glutathione assay.ResultsIndeed, quinone formation increased with increasing doses of methylphenidate. Additionally, methylphenidate dose-dependently resulted in a depletion of glutathione, which was further depleted following MPTP treatment.ConclusionsThus, the increased sensitivity of dopamine neurons to MPTP toxicity following chronic methylphenidate exposure may be due to quinone production and subsequent depletion of glutathione.     

重组蝎毒素基因表达的研究进展

目的介绍重组蝎毒素基因表达的研究进展。方法根据近年来国内外公开发表的有关研究论文 ,综述重组蝎毒素基因表达的研究。结果与结论通过筛选得到的蝎毒素基因或化学合成的编码蝎毒素的基因分别在大肠杆菌、酵母细胞、哺乳动物细胞、昆虫和植物中都有过表达尝试。重组蝎毒素基因表达的关键是如何使有活性的重组蛋白高水平表达     

Methamphetamine-induced stereotypy correlates negatively with patch-enhanced prodynorphin and arc mRNA expression in the rat caudate putamen: The role of mu opioid receptor activation

Amphetamines induce stereotypy, which correlates with patch-enhanced c-Fos expression the patch compartment of caudate putamen (CPu). Methamphetamine (METH) treatment also induces patch-enhanced expression of prodynorphin (PD), arc and zif/268 in the CPu. Whether patch-enhanced activation of any of these genes correlates with METH-induced stereotypy is unknown, and the factors that contribute to this pattern of expression are poorly understood. Activation of mu opioid receptors, which are expressed by the neurons of the patch compartment, may underlie METH-induced patch-enhanced gene expression and stereotypy. The current study examined whether striatal mu opioid receptor blockade altered METH-induced stereotypy and patch-enhanced gene expression, and if there was a correlation between the two responses. Animals were intrastriatally infused with the mu antagonist CTAP (10 μg/μl), treated with METH (7.5 mg/kg, s.c.), placed in activity chambers for 3 h, and then sacrificed. CTAP pretreatment attenuated METH-induced increases in PD, arc and zif/268 mRNA expression and significantly reduced METH-induced stereotypy. Patch-enhanced PD and arc mRNA expression in the dorsolateral CPu correlated negatively with METH-induced stereotypy. These data indicate that mu opioid receptor activation contributes to METH-induced gene expression in the CPu and stereotypy, and that patch-enhanced PD and arc expression may be a homeostatic response to METH treatment.     

Activations of c-fos/c-jun signaling are involved in the modulation of hypothalamic superoxide dismutase (SOD) and neuropeptide Y (NPY) gene expression in amphetamine-mediated appetite suppression

Amphetamine (AMPH) is known as an anorectic agent. The mechanism underlying the anorectic action of AMPH has been attributed to its inhibitory action on hypothalamic neuropeptide Y (NPY), an appetite stimulant in the brain. This study was aimed to examine the molecular mechanisms behind the anorectic effect of AMPH. Results showed that AMPH treatment decreased food intake, which was correlated with changes of NPY mRNA level, but increased c-fos, c-jun and superoxide dismutase (SOD) mRNA levels in hypothalamus. To determine if c-fos or c-jun was involved in the anorectic response of AMPH, infusions of antisense oligonucleotide into the brain were performed at 1 h before daily AMPH treatment in freely moving rats, and the results showed that c-fos or c-jun knockdown could block this anorectic response and restore NPY mRNA level. Moreover, c-fos or c-jun knockdown could partially block SOD mRNA level that might involve in the modulation of NPY gene expression. It was suggested that c-fos/c-jun signaling might involve in the central regulation of AMPH-mediated feeding suppression via the modulation of NPY gene expression.     

Oral administration of BDNF and/or GDNF normalizes serum BDNF level in the olfactory bulbectomized rats: A proof of concept study

BackgroundNeurotrophins, especially brain-derived neurotrophic factor (BDNF) have gained significant therapeutic interest particularly in neurologic and psychiatric disorders and they have been found in human breast milk of mothers who suffered from adverse outcomes in pregnancy. This study tested the hypothesis that oral administration of BDNF/GDNF (glial cell line-derived neurotrophic factor) can exert a biological effect in a rat model of severe neuropathology induced by olfactory bulbectomy (OBX), which exhibits dysregulation of BDNF signaling and impaired blood-brain barrier.MethodsAdult male albino Sprague-Dawley rats underwent the OBX surgery and separate groups of OBX and sham-operated controls received one oral dose of vehicle, BDNF (0.005 mg/kg), GDNF (0.03 mg/kg) or their combination. One week after neurotrophin dosing the rats were sacrificed and BDNF level was assessed by ELISA in the blood serum and cerebrospinal fluid.ResultsA significant decrease of serum BDNF level was found in the OBX model. This alteration was normalized by all types of treatment BDNF, GDNF, or their combination. No influence of sham surgery or treatment was observed in the control rats. BDNF levels in cerebrospinal fluid were below detection limit.ConclusionThis study indicates that oral administration of neurotrophins is able to exert a biological effect in the OBX model. There is a number of potential mechanisms, which remain to be elucidated.     

Gene expression profiling in the hippocampus of adolescent rats after chronic alcohol administration

In South Korea, the average age of onset of alcohol drinking is 13.3 years and half of adolescents drink alcohol more than once a month; 8.45% of the Korean adolescent population become future high‐risk alcohol drinkers. Chronic alcohol abuse causes physical and psychiatric health problems such as alcohol addiction, liver disease, stroke and cognitive impairments. This study aimed to investigate the effect of alcohol on gene expression and their function in the hippocampus of adolescent rats. After chronic alcohol administration in male (control, n = 6; alcohol, n = 6) Sprague‐Dawley rats for 6 weeks, we analysed up‐ or down‐regulated genes using RNA‐sequencing technology. We found 83 genes more than 1.5‐fold up‐ or down‐regulated in the alcohol‐treated group. Among them, genes (Dnai1, Cfap206 and Dnah1) associated with cilium movement were up‐regulated in the alcohol‐treated group. Mlf1, related to cell cycle arrest, was also up‐regulated in the alcohol‐treated group. On the other hand, genes (Smad3 and Plk5) involved in negative regulation of cell proliferation were down‐regulated in the hippocampus by chronic alcohol administration. In addition, expression levels of genes associated with oxidative stress (Krt8 and Car3) and migration (Vim) were changed by chronic alcohol administration. These results pave a path for a better understanding of the neuromolecular mechanisms mediated by chronic alcohol exposure in the hippocampus of adolescents and negative pathology due to chronic alcohol abuse.     

Evaluation of the in vivo genotoxicity of liposomal formulation for delivering anticancer estrogenic derivative (ESC8) in a mouse model

The genotoxic potential of glucocorticoid receptor (GR)-targeted liposomal formulations of the anticancer drug molecule ESC8 was studied in vivo. A methodical literature review discovered no previous studies on the genotoxicity of ESC8. Genotoxicity was assessed in both male and female mice by various assay systems, such as comet assay, chromosomal aberrations and micronuclei assay, which detect different abnormalities. Eleven groups of male mice and eleven groups of female mice, containing six animals per group, were used in the present study: group I served as vehicle control; group II received the positive control (cyclophosphamide 40 mg/kg; CYP); and animals in group III to XI received free drug (ESC8), DX liposome and drug-associated DX liposomal formulation (DXE), respectively, dissolved in 5% solution of glucose at a drug-dose of 1.83, 3.67 and 7.34 mg/kg, respectively. Same drug treatments were followed for the female mice groups. The obtained data revealed the safety of DXE, which did not show substantial genotoxic effects at different dose levels. In contrast, the positive control, CYP, exhibited highly substantial irregular cytogenetic variations in comparison with the control group in different assays.     

Roles of chlorophyllin in cell proliferation and the expression of apoptotic and cell cycle genes in HB4a non-tumor breast cells

Chlorophyllin (Chl) has attracted interest in the scientific community due to its chemopreventive and antimutagenic properties. However, the molecular mechanisms of action of Chl remain unclear. This study assesses the effects on cell proliferation and the expression of genes involved in apoptosis, and the cell cycle in HB4a cells treated with Chl. Chl was cytotoxic and induced apoptosis to HB4a cells at 400?μg/mL. Analysis of gene expression showed that there was a decrease in the mRNA level of BIRC5 and CCNA2 genes involved in apoptosis and cell cycle progression, respectively. The proapoptotic gene BAX and the antiapoptotic genes BCL-2 and BCL-XL were upregulated. The cytotoxicity of Chl has been attributed to increases in the expression of BAX and decreases in the expression of genes involved in the cell cycle, but increases in the expression of anti-apoptotic genes suggests a mechanism for protection from cell death induced by Chl. This study provides important information about mechanisms that protect against or trigger damaging processes in non-tumor cells.     

Effects of standard treatment on the dynamics of matrix metalloproteinases gene expression in patients with acute coronary syndromes

Inflammation plays a critical role in the pathology of acute coronary syndrome (ACS). Matrix metalloproteinases (MMP)--proteolytic enzymes participating in plaque destabilization--are the crucial effectors of proinflammatory mechanisms leading to plaque rupture. Numerous reports have confirmed the significance of these factors both in circulating blood and locally in the plaque. There is, however, a lack of information on the molecular mechanisms leading to these disturbances, and the effect of standard treatment for ACS on these processes. The aim of the study was to assess the gene expression of MMP-2, -9 and TIMP-2, and the effect of standard treatment on the expression of the studied genes. The study was conducted in 32 patients with ACS and 15 healthy subjects (control group). Monocytes were isolated using Rosette-Sep kits. Gene expression of MMP-2, MMP-9 and TIMP-2 was evaluated on days 1 and 5 in the studied group and once in controls. Total mRNA was extracted from monocytes and the number of mRNA copies was assessed by QRT-PCR. Monocytes of ACS patients present with significantly higher gene expression of MMP-2, -9 and TIMP-2 compared to healthy controls (0.0915 ± 0.037 vs. 0.001 ± 0.0002, p < 0.01; 0.81 ± 0.279 vs. 0.10 ± 0.057, p < 0.05; 0.84 ± 0.140 vs. 0.42 ± 0.126, p < 0.05, respectively). After the 5-day standard treatment, a significant decrease in MMP-2 gene expression was observed. Other studied genes did not show relevant changes during the observation period. No significant correlation was found between classical atherosclerosis risk factors and the expression of the studied genes. Monocytes of ACS patients significantly overexpressed MMP-2, MMP-9 and TIMP-2. Five days of standard treatment resulted in downregulation of the MMP-2 gene. MMP gene overexpression appears to be an independent factor concerning the pathogenesis of ACS.     

Vitamin D supplementation alters the expression of genes associated with hypertension and did not induce DNA damage in rats

Vitamin D3 deficiency has been correlated with altered expression of genes associated with increased blood pressure (BP); however, the role of vitamin D3 supplementation in the genetic mechanisms underlying hypertension remains unclear. Thus, the aim of this study was investigate the consequences of vitamin D3 supplemented (10,000 IU/kg) or deficient (0 IU/kg) diets on regulation of expression of genes related to hypertension pathways in heart cells of spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) controls. An additional aim was to assess the impact of vitamin D3 on DNA damage and oxidative stress markers. The gene expression profiles were determined by PCR array, DNA damage was assessed by an alkaline comet assay, and oxidative stress markers by measurement of thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) levels. In SHR rats data showed that the groups of genes most differentially affected by supplemented and deficient diets were involved in BP regulation and renin-angiotensin system. In normotensive WKY controls, the profile of gene expression was similar between the two diets. SHR rats were more sensitive to changes in gene expression induced by dietary vitamin D3 than normotensive WKY animals. In addition to gene expression profile, vitamin D3 supplemented diet did not markedly affect DNA or levels of TBARS and GSH levels in both experimental groups. Vitamin D3 deficient diet produced lipid peroxidation in SHR rats. The results of this study contribute to a better understanding of the role of vitamin D3 in the genetic mechanisms underlying hypertension.

Abbreviations: AIN, American Institute of Nutrition; EDTA, disodium ethylenediaminetetraacetic acid; GSH, glutathione; PBS, phosphate buffer solution; SHR, spontaneously hypertensive rats; TBARS, thiobarbituric acid reactive substances; WKY, Wistar Kyoto.     

Behavioral sensitization to cocaine after a brief social defeat stress: c-fos expression in the PAG

The experiments explored the nature and time course of changes in behavior and Fos expression in the periaqueductal grey area (PAG) in response to an injection of cocaine that was given following a single episode of social defeat stress. Social defeat stress was defined as an intruder mouse’s response to an aggressive resident mouse. First, the intruder was briefly attacked, and secondly, it was threatened while protected by a perforated cage for 20 min. Plasma corticosterone levels rose after the beginning of the confrontation and remained elevated during the protected phase. In a first experiment, separate groups of intruder and control mice were challenged once with cocaine (20, 30, or 40 mg/kg) or saline. During tests for motor activity, behavioral measurements were obtained via (1) photobeam interruptions, (2) tracking of movements via image analysis, and (3) quantitative ethological analysis of postures and acts via videorecords. Several indices of ambulatory or horizontal forward locomotion confirmed the stimulant effects of cocaine. In a further experiment, separate groups of mice were challenged with 40 mg/kg cocaine at one time point, either during the social stress or 3, 5, 7 or 9 days thereafter. A cocaine challenge significantly increased locomotion 5 and 7 days after a brief social defeat stress, in excess of the level that is seen in non-stressed animals. Further experiments used immunohistochemical assays of sections through the caudal ventrolateral PAG and showed a significant increase in Fos-like immunoreactivity (Fos-LI) 1 h after the social stress experience or after cocaine. Importantly, concurrent administration of cocaine with social defeat stress produced inhibition of Fos expression throughout the PAG. A partial to complete recovery of cocaine-induced Fos expression was observed 5–7 days after social defeat stress. The results suggest that a single social stress episode is sufficient to engender a delayed sensitization of stimulant hyperactivity. The initial inhibition of Fos expression by concurrent social stress and cocaine may point to a relevant initiating event in the process of sensitization to stimulants. Received: 30 July 1997/Final version: 15 June 1998     

Chronic methamphetamine exposure suppresses the striatal expression of members of multiple families of immediate early genes (IEGs) in the rat: normalization by an acute methamphetamine injection

Rationale  

Repeated injections of cocaine cause blunted responses to acute cocaine challenge-induced increases in the expression of immediate early genes (IEGs).     

Dietary therapeutic dose of oxytetracycline negatively influences the antioxidant capacity and immune-related genes expression in Nile tilapia Oreochromis niloticus (L.)

Effects of the dietary therapeutic dose of oxytetracycline (OTC) at 80 mg/kg biomass/day for consecutive 10 days on the behaviour, feed intake, mortality, residue accumulation and depletion, antioxidant capacity and immune-related genes expression in juvenile Nile tilapia Oreochromis niloticus were evaluated. OTC-dosing caused mortalities, reduced feed intake, and biomass reduction at 24.5–28.5 °C. OTC residues recorded on day 10 (161.40 ± 11.10 ng/g) were within the maximum residue limits of the Codex Alimentarius. The withdrawal period was 7 days as per the European Commission's regulation. Traces of residues were present even on day 42 post-OTC-dosing. Dietary OTC reduced the antioxidant capacity of the liver and muscle tissues and down-regulated the expression of tumour necrosis factor-α, interleukin-1β, and heat shock protein-70 genes in the liver significantly during the dosing period. The data generated on the biosafety of OTC-dosing may offer inputs for the development of management strategies in maintaining fish health and food safety.     

藻蓝蛋白对大鼠脑缺血再灌注损伤的保护作用及对Caspase-3 mRNA表达的影响

目的探讨藻蓝蛋白对大鼠脑缺血再灌注损伤的保护作用及对Caspase-3 mRNA表达的影响。方法应用线栓法建立大鼠大脑中动脉阻塞再灌注(MCAO/R)模型,随机分为假手术组4只、对照组40只和治疗组40只,应用藻蓝蛋白进行干预治疗,通过Bederson法评价大鼠的神经功能缺失症状,氯化三苯基四氮唑染色测量脑梗塞体积,原位杂交技术检测脑缺血再灌注后不同时段Caspase-3 mRNA的表达。结果脑缺血再灌注24~48h,治疗组神经功能缺损评分和脑梗死体积明显低于对照组。脑缺血再灌注6h,对照组Caspase-3mRNA阳性细胞数开始增加,至再灌注24h达高峰,2d后逐渐减少,至14d仍有表达。治疗组Caspase-3 mR-NA阳性细胞的数量相对较少,其变化规律与对照组相似,同一时间点相比较均显著低于对照组。结论藻蓝蛋白可下调Caspase-3 mRNA的表达,对脑缺血再灌注损伤有显著保护作用。     

Changes in transferrin and hepcidin genes expression in the liver of the fish Pseudosciaena crocea following exposure to cadmium

Water pollution of heavy metals such as cadmium is a serious problem in China. Cadmium is toxic to cellular processes such as the transport and metabolism of iron. The nucleotide sequences of serum transferring (c-sTf) and hepcidin (c-Hep) genes from croceine croaker (Pseudosciaena crocea) were determined. The full-length cDNAs of c-sTf and c-Hep were 2,486 and 850 nt, respectively. After cadmium exposure (CdE), fish serum iron increased significantly and reached a high level at 24 h, after which it decreased and reached normal levels after 72 h. TIBC increased to a high level at 24 h and maintained that to the end of the experiment. Tf saturation increased to a high level at 24 h, then decreased and returned to normal after 72 h. Higher erythrocyte numbers in the blood were found after 24 h. c-sTf mRNA in fish liver significantly increased at 24 h and maintained to the end of the experiment. c-Hep mRNA expression significantly increased at 24 h and reached a high level at 48 h, then decreased to normal by 72 h. Therefore, it suggests that iron status was the signal for mRNA expression of hepcidin in liver, while erythrocytes changes in blood were the signals for that of sTf.