High doses of dietary zinc induce cytokines, chemokines, and apoptosis in reproductive tissues during regression

In chickens, high levels of dietary zinc cause molting, and the reproductive system undergoes complete remodeling concomitant to feather replacement. In the present study, the expression profiles of cytokines and chemokines were investigated in the ovary and oviduct of control hens and of hens induced to molt by zinc feeding. The zinc-induced feed-intake suppression, the changes in corticosterone levels, the immune cell populations in the reproductive tract, and the apoptosis of reproductive tissues were analyzed. The expression of mRNAs for interleukin-6 (IL-6), interferon-γ (IFN-γ), the avian ortholog of mammalian IL-8 (chCXCLi2), and a chicken MIP-1β-like chemokine (chCCLi2) in the ovary and of mRNAs for IL-1β, IL-6, IFN-γ, transforming growth factor-β2, chCXCLi2, and chCCLi2 in the oviduct were upregulated significantly during zinc-induced molting. A simultaneous feed-intake reduction was observed with higher expression of cytokines and chemokines. The results of the present investigation also suggested that the upregulation of corticosterone was closely associated with the increased expression of cytokines and chemokines. An increase in apoptosis within reproductive tissue during tissue regression was also noted. We had previously observed the upregulation of these cytokines expression in an earlier study (molting by feed withdrawal). However, the pattern and the level of expression were different among these two methods. These findings indicate that cytokines might be a common mediator of tissue regression during molting induced by diverse methods, although the pattern of induction is different. Thus, a high dose of dietary zinc seems to induce reproductive regression via the upregulation of cytokines and chemokines, the suppression of feed intake, and the increase in serum corticosterone, resulting finally in the apoptosis of reproductive tissues.     

Evaluation of inhibitory effect and apoptosis induction of Zyzyphus Jujube on tumor cell lines,an in vitro preliminary study

In the present study, water extract of dried fruit of Zyzyphus Jujube was tested for its possible anticancer effect and induction of apoptosis on human tumor cell lines, HEp-2, HeLa and Jurkat cell lines. The inhibitory effect of water extract of this fruit on cell proliferation was assessed by MTT colorimetric assay. The induction of apoptosis of this extract was analyzed by DNA fragmentation analysis. Zyzyphus Jujube extract showed inhibitory effects on mentioned cell lines. Jurkat leukemic line was found the most sensitive cells with IC50 of 0.1 μg mL⁻¹. Our study also showed a typical DNA laddering in this cell line. The present study showed cytotoxic activity of Zyzyphus Jujube on tumor cells. Although Zyzyphus Jujube has useful compounds for medical applications.     

Gold ions bio-released from metallic gold particles reduce inflammation and apoptosis and increase the regenerative responses in focal brain injury

Traumatic brain injury results in loss of neurons caused as much by the resulting neuroinflammation as by the injury. Gold salts are known to be immunosuppressive, but their use are limited by nephrotoxicity. However, as we have proven that implants of pure metallic gold release gold ions which do not spread in the body, but are taken up by cells near the implant, we hypothesize that metallic gold could reduce local neuroinflammation in a safe way. Bio-liberation, or dissolucytosis, of gold ions from metallic gold surfaces requires the presence of disolycytes i.e. macrophages and the process is limited by their number and activity. We injected 20-45 mum gold particles into the neocortex of mice before generating a cryo-injury. Comparing gold-treated and untreated cryolesions, the release of gold reduced microgliosis and neuronal apoptosis accompanied by a transient astrogliosis and an increased neural stem cell response. We conclude that bio-liberated gold ions possess pronounced anti-inflammatory and neuron-protective capacities in the brain and suggest that metallic gold has clinical potentials. Intra-cerebral application of metallic gold as a pharmaceutical source of gold ions represents a completely new medical concept that bypasses the blood-brain-barrier and allows direct drug delivery to inflamed brain tissue.     

The Protective Effect of Dexanabinol (HU-211) on Nitric Oxide and Cysteine Protease-Mediated Neuronal Death in Focal Cerebral Ischemia

We hypothesized that dexanabinol can prevent neuronal death by protecting neuronal lysosomes from nitric oxide (NO)-mediated toxicity, and in turn, by suppressing the release of cathepsins during cerebral ischemia. Focal cerebral ischemia was induced in two sets of animals by permanent middle cerebral artery occlusion. The first set was used to monitor NO concentration and cathepsin activity, while the second was used for histological examination with hematoxylin and eosin, and TUNEL staining. In post-ischemic brain tissue, NO content and cathepsin B and L activity increased (p < 0.05). Dexanabinol treatment reduced NO concentration and cathepsin activity to the control level (p > 0.05). The number of eosinophilic and apoptotic neurons increased in the post-ischemic cerebral cortex (p < 0.05). However, dexanabinol treatment lowered both of these (p < 0.05). We conclude that dexanabinol might be a useful agent for the treatment of stroke patients.     

Cell Death is Associated with Reduced Base Excision Repair During Chronic Alcohol Administration in Adult Rat Brain

The cell death cascades in different brain regions namely hippocampus and frontal cortex of rats fed with 10% (v/v) ethanol for 12 weeks, was examined. After Western blotting, different cell death associated proteins displayed differential activation in the two regions observed. In hippocampus, activated caspase-3 and caspase-7 resulted in subsequent cleavage of poly(ADP-ribose) polymerase-1 (PARP-1). Cytochrome c release to cytosol and apoptosis inducing factor (AIF) translocation to nucleus was marginal. B-cell leukemia/lymphoma-2 (Bcl-2) translocation to cytosol was significant whereas Bcl-2-associated X protein (Bax) and Bcl-associated death protein (Bad) were largely located in cytosol. Further, upregulation of N-methyl d-aspartate receptor subunit 1 (NMDAR1), N-methyl d-aspartate receptor subunit 2B (NMDAR2B), N-methyl d-aspartate receptor subunit 2C (NMDAR2C) and activation of calpains were observed. In frontal cortex, caspase-3 activation, cleavage of PARP-1 and nuclear translocation of AIF were more pronounced. Moreover, cytochrome c release to cytosol, Bcl-2 translocation to cytosol was evident. However, levels of Bax, Bad, NMDA receptor subunits, and calpains were unaffected. Apoptosis was further substantiated by in situ staining for terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL). Results of the current study revealed that frontal cortex exhibits a higher level of ethanol-induced apoptosis relative to hippocampus. DNA polymerase beta assay and immunoblot showed significant loss in base excision repair in ethanol treated group.     

AcMNPVP35抑制HaSNPV诱导的Tn-Hi5细胞凋亡

苜蓿银纹夜蛾核多角体病毒(Autographa californica multicapsid nuclear polyhedrosis virus,AcMNPV)能够抑制棉铃虫核多角体病毒(Helicoverpa armigera Nucleopoly hedrovirus,HaSNPV)诱导的Tn Hi5 细胞凋亡,并能辅助HaSNPV在Tn Hi5细胞中复制,产生具有感染能力的子代病毒。瞬时表达实验证明,在Tn Hi5细胞中,p35具有明显抑制凋亡的能力,但是不能辅助HaSNPV在Tn Hi5细胞中的复制;进一步构建超表达p35 的重组病毒:vHap35,发现vHap35能够抑制Tn Hi5细胞凋亡,但是不能产生具有感染力的病毒粒子。电镜观察发现感染重组病毒的部分细胞中存在单粒包埋的病毒粒子(ODV)。     

BTV及其dsRNA分子诱导IFN产生和细胞凋亡

在离体培养细胞上探讨BTV(BluetongueVirus,BTV)和BTVdsRNA分子诱导人宫颈癌Hela细胞IFN(Interferon)产生和凋亡的生物医学作用。离体培养的人宫颈癌Hela细胞单层分别施以不同水平的蓝舌病毒(BTV)和脂质体包裹的BTVdsRNA等因素处理,比较研究不同处理后细胞形态学差异;并通过MTT法检测不同处理条件下细胞存活率的差异;ELISA试剂盒检测培养细胞上清液中IFN含量及流式细胞仪检测细胞凋亡率。分析了不同处理条件下不同用量的病毒及不同浓度的RNA脂质体复合物诱导培养细胞产生IFN量的差异,揭示了不同因素和不同水平处理下,Hela细胞IFN产量具有显著性差异(p<0.05),而BTVdsRNA诱导人宫颈癌Hela细胞凋亡能力低于BTV(p<0.05)。BTVdsRNA可显著诱导人宫颈癌细胞产生IFN和凋亡,推断BTVdsRNA具有发展成为新的干扰素诱导剂的潜能。     

羊栖菜多糖诱导lovo细胞凋亡及其机理探讨

本课题研究羊栖菜多糖(Sargassum Fusiforme Polysaccharides,SFPS)诱导人大肠癌lovo细胞凋亡及凋亡过程中Caspase-3的变化及其意义。MTT法检测SFPS对大肠癌细胞增殖的抑制率;通过电镜、琼脂糖凝胶电泳、流式细胞术鉴定细胞凋亡;应用Western blot法测定Caspase-3酶原的变化; RT-PCR检测Caspase-3 mRNA表达。结果显示:SFPS作用lovo细胞24,36,48和72h的IC_(50)分别为375,355,178和60mg/L,表明对lovo细胞具有显著生长抑制作用。在电镜下,可见明显的细胞凋亡特征:细胞膜表面微绒毛减少、染色质固缩、边集,凋亡小体形成。在琼脂糖凝胶电泳中,药物浓度为5-300mg/L作用24h后,显示有凋亡细胞特有的DNA梯状条带;而500mg/L处理后梯状条带模糊,开始出现“涂片状”,表明在高药物浓度的作用下,细胞有坏死。流式细胞仪测得细胞凋亡率有剂量的依赖性;DNA直方图出现亚G1峰,但细胞周期时相的分布无明显改变。SFPS处理lovo细胞后,发现Caspase-3酶原蛋白表达降低,Caspase-3的mRNA高表达,并具有剂量和时间的依赖性。实验结果提示,SFPS在体外能够诱导lovo细胞凋亡,这可能是SFPS抑制肿瘤增殖的机制之一,而Caspase-3的活化参与了SFPS诱导lovo细胞凋亡的调控。     

Apoptosis may contribute to false-positive results in the in vitro micronucleus test performed in extreme osmolality, ionic strength and pH conditions

Conditions in which clastogens produce positive responses have been increasingly challenged, and several situations have been described in which clastogenic responses would be considered not to be relevant. For example, extreme culture conditions lead to high variations of pH, osmolality or ionic strength. Apoptosis is induced in extreme culture conditions and contributes to false-positive results in the in vitro micronucleus test performed with CTLL-2 cells. These cells can enter apoptosis when exposed to apoptosis stimuli or after IL-2 deprivation, whereas the CTLL-2 Bcl2 cell line is protected from apoptosis due to the over-expression of the apoptosis inhibitor Bcl2 in bcl2-transfected CTLL-2 cells. The two cell lines were treated in extreme culture conditions of either pH or osmolality or were submitted to high ionic strength. The apoptosis level was measured in parallel with the in vitro micronucleus test using the annexin V-FITC method. Data obtained in the two cell lines suggested that apoptosis caused by extreme culture condition induces the formation of micronucleated cells, which leads to false-positive results in the in vitro micronucleus test.