Dietary Green Tea Extract and Antioxidants Improve Insulin Secretory Functions of Pancreatic β-Cells in Mild and Severe Experimental Rodent Model of Chronic Pancreatitis

Chronic pancreatitis (CP) is a progressive inflammatory disorder of the pancreas. It is predominantly idiopathic (with an unknown cause) in India and mostly due to alcohol in the West. Diabetes that occur secondary to chronic pancreatitis (T3c Diabetes) is often brittle, and is difficult to attain normoglycemia with conventional treatment requiring multiple doses of insulin. Mild and severe model of CP was induced in mice by repeated intraperitoneal injections of cerulein and L-arginine respectively with an intent to study islet dysfunction and develop therapeutic strategy in animal models of CP. Dietary intervention of epigallocatechin-3-gallate (EGCG) was tested in both the models of CP for its beneficial effects on insulin secretory functions. Pancreata collected upon euthanasia were used to study alterations in the morphology of pancreatic parenchyma and inflammation by staining with H&E and fibrotic changes by Masson’s trichrome and picrosirius staining. Insulin secretory functions of islets were evaluated to test the efficacy of the dietary intervention on β-cell functions. Intraperitoneal glucose tolerance test was performed to monitor the glucose homeostasis before and after the dietary intervention. Both the models resulted in CP with dispersed acini, inflammation and fibrosis. The loss of acini and extent of fibrosis was more in L-arginine model. 2-fold improvement in glucose-stimulated insulin secretory functions of islets was observed with 0.5% EGCG dietary intervention in cerulein model of CP and 1.6-fold in L-arginine model of CP. A further improvement in insulin secretion by 3.2-fold was observed with additional dietary supplements like N-acetyl cysteine, curcumin in combination with EGCG. Our results thus demonstrate and highlight the therapeutic potential of dietary green tea (EGCG) supplementation in reversing islet dysfunction and improving glucose homeostasis in experimental chronic pancreatitis in mice.

异氟烷对FVB/N小鼠和C57BL/6小鼠超声心动图参数的影响

目的评价异氟烷对FVB/N小鼠和C57BL/6小鼠超声心动图参数的影响。方法使用Visual Sonics Vevo770高分辨率小动物超声仪测量雄性FVB/N小鼠和C57BL/6小鼠超声心动图参数,比较异氟烷对两种品系小鼠心功能及心脏结构的影响。结果 FVB/N小鼠在1%和2%异氟烷麻醉下,心脏收缩功能和心脏结构指标均正常,但FVB/N小鼠在1%异氟烷麻醉下容易觉醒,不易获取清晰稳定的图像;C57BL/6小鼠在1%异氟烷麻醉下能够维持良好的收缩功能,但在2%异氟烷麻醉下,C57BL/6小鼠的收缩功能明显被抑制。结论 2%异氟烷麻醉适用于FVB/N小鼠,1%异氟烷麻醉适用于C57BL/6小鼠。

Glycosylation of the hemagglutinin protein of H9N2 subtype avian influenza virus influences its replication and virulence in mice

N-Linked glycosylation of hemagglutinin(HA) has been demonstrated to regulate the virulence and receptor-binding specificity of avian influenza virus(AIV).In this study,we characterized the variation trend of naturally isolated H9 N2 viruses for the potential N-linked glycosylation sites in HA proteins,and explored any important role of some glycosylation sites.HA genes of 19 H9 N2 subtype AIV strains since 2001 were sequenced and analyzed for the potential glycosylation sites.The results showed that the viruses varied by losing one potential glycosylation site at residues 200 to 202,and having an additional one at residues 295 to 297 over the past few years.Further molecular and single mutation analysis revealed that the N200 Q mutation lost an N-linked glycosylation at positions 200 to 202 of the HA protein and affected the human-derived receptor affinity.We further found that this N-linked glycosylation increased viral productivity in the lung of the infected mice.These findings provide a novel insight on understanding the determinants of host adaption and virulence of H9 N2 viruses in mammals.

Improved method for inducing chronic atrophic gastritis in mice

BACKGROUND Chronic atrophic gastritis(CAG)is a common disease of the digestive system with pathological characteristics of a decreasing number,or disappearance,of inherent glands of the gastric mucosa.CAG has been defined as a precancerous condition of gastric cancer.Intestinal metaplasia or intraepithelial neoplasia accompanying atrophied glands of the stomach is regarded as one of the most important precancerous lesions of gastric cancer.As a common malignant tumour,gastric cancer remains without a satisfactory therapy and its pathogenesis remains unclear,seriously threatening human life.Therefore,some scholars have proposed to prevent the incidence of gastric cancer by avoiding precancerous lesions.If CAG can be reversed,the incidence of gastric cancer can be substantially reduced.To reverse and prevent CAG and study its pathogenesis and therapy,it is necessary to develop an ideal,safe,stable,animal model.AIM To study a rapid,stable,and safe method of establishing a mouse model of human CAG.METHODS Six-week-old Kunming mice were divided into a phosphate buffered solution control group,a Helicobacter pylori(H.pylori)group,an N-methyl-N'-nitroguanidine(MNNG)group,an ammonia water group,and a group combining H.pylori,MNNG,and ammonia water(hereinafter referred to as the combined group).The mice were administrated with drinking water containing ammonia or infected with H.pylori through gavage.At the 30th,60th,90th,and 120th day after the last H.pylori infection,mice were selected randomly to collect their gastric mucosa for hematoxylin eosin staining,terminal nick-end labelling staining detection,and immunohistochemical staining for Bax and Bcl-2.In addition,H.pylori was isolated,cultured,and identified,and its extent of colonisation calculated.Blood was collected to detect inflammatory factors interleukin(IL)-1β,IL-8,and tumor necrosis factor(TNF)-αand immune function markers CD4 and CD8 to confirm successful establishment of the CAG model.RESULTS The combined group showed slight CAG at the 90th day and moderate CAG at the 120th day,while other groups did not show CAG at that time.CONCLUSION The combination of H.pylori,MNNG,and ammonia is an effective method of developing a mouse model of human CAG.

Di-(n-butyl)-phthalate-induced Oxidative Stress and Depression-like Behavior in Mice with or without Ovalbumin Immunization

Objective To investigate the relationship between atopic allergy and depression and the role of DBP in the development of depression. Methods BALB/c mice were randomly divided into eight groups：saline;ovalbumin （OVA）-immunized;saline＋DBP （0.45 mg/kg·183;d）; saline＋DBP （45 mg/kg·d）; DBP （0.45 mg/kg·d） OVA-immunized; DBP （45 mg/kg·d） OVA-immunized; saline＋hydrocortisone （30 mg/kg·d）; and hydrocortisone （30 mg/kg·d）-exposed OVA-immunized. Behavior （e.g. open-field, tail suspension, and forced swimming tests）, viscera coefficients （brain and spleen）, oxidative damage [e.g. reactive oxygen species （ROS）, malondialdehyde （MDA）, and glutathione （GSH）], as well as levels of IgE and IL-4, were then analyzed. Results In the saline and OVA groups, the degree of depression symptoms in mice increased with increasing DBP concentration. Additionally, the OVA-immunity groups were associated with more serious depressive behavior compared with the same exposure concentration in the saline group. Oxidative damage was associated with a dose-dependent increase in DBP in the different groups. IL-4 and IgE levels were associated with low-dose DBP stimulation, which changed to high-dose inhibition with increasing DBP exposure, possibly due to spleen injury seen at high DBP concentrations.Conclusion Development of an atopic allergy has the potential to increase the risk of depression in mice, and it seems that DBP helps OVA to exert its effect in our present model. Moreover, the results of our study implicate a certain connection between brain oxidative stress and depression, which deserves a further exploration.

Dietary Nε-(carboxymethyl)lysine affects cardiac glucose metabolism and myocardial remodeling in mice

BACKGROUND Myocardial remodeling is a key factor in the progression of cardiovascular disease to the end stage.In addition to myocardial infarction or stress overload,dietary factors have recently been considered associated with myocardial remodeling.Nε-(carboxymethyl)lysine(CML)is a representative foodborne toxic product,which can be ingested via daily diet.Therefore,there is a marked need to explore the effects of dietary CML on the myocardium.AIM To explore the effects of dietary CML(dCML)on the heart.METHODS C57 BL/6 mice were divided into a control group and a dCML group.The control group and the dCML group were respectively fed a normal diet or diet supplemented with CML for 20 wk.Body weight and blood glucose were recorded every 4 wk.^(18)F-fluorodeoxyglucose(FDG)was used to trace the glucose uptake in mouse myocardium,followed by visualizing with micro-positron emission tomography(PET).Myocardial remodeling and glucose metabolism were also detected.In vitro,H9C2 cardiomyocytes were added to exogenous CML and cultured for 24 h.The effects of exogenous CML on glucose metabolism,collagen I expression,hypertrophy,and apoptosis of cardiomyocytes were analyzed.RESULTS Our results suggest that the levels of fasting blood glucose,fasting insulin,and serum CML were significantly increased after 20 wk of dCML.Micro-PET showed that ^(18)F-FDG accumulated more in the myocardium of the dCML group than in the control group.Histological staining revealed that dCML could lead to myocardial fibrosis and hypertrophy.The indexes of myocardial fibrosis,apoptosis,and hypertrophy were also increased in the dCML group,whereas the activities of glucose metabolism-related pathways and citrate synthase(CS)were significantly inhibited.In cardiomyocytes,collagen I expression and cellular size were significantly increased after the addition of exogenous CML.CML significantly promoted cellular hypertrophy and apoptosis,while pathways involved in glucose metabolism and level of Cs mRNA were significantly inhibited.CONCLUSION This study reveals that dCML alters myocardial glucose metabolism and promotes myocardial remodeling.

Effect of N-Carbamylglutamate(NCG) on Growth Performance of ICR Mice

To understand the effects of self synthesized N-carbamylglutamate（NCG） on growth performance of ICR mice,mice were fed with the basal diet adding with 0.025%,0.05% and 0.1% NCG for 28 d.Effects of different levels of NCG on body weight of mice were observed.The re-sults showed that the addition of NCG in the feed could improve the growth performance of mice,and the growth-promoting effect enhanced with the increasing dose.

Schisandra N-butanol extract improves synaptic morphology and plasticity in ovarectomized mice

Preliminary work by our research team revealed that Schisandra, a renowned traditional Chinese medicine, causes learning and memory improvements in ovariectomized mice. This activity was attributed to active ingredients extracted with N-butyl alcohol, named Schisandra N-butanol extract. In this study, ovariectomized mice were pretreated with Schisandra N-butanol extract given by intragastric administration. This treatment led to the enhancement of learning, and an increase in hippocampal CA1 synaptic, surface and postsynaptic density. A decrease in the average size of the synaptic active zone was also observed. These experimental findings showing that Schisandra N-butanol extract improved synaptic morphology indicate an underlying mechanism by which the ability of learning is enhanced in ovariectomized mice.

N,N-二甲基甲酰胺对炔雌醚不育作用和适口性的影响

【目的】明确添加高效、安全的助剂N,N-二甲基甲酰胺(N,N-Dimethylformamide,DMF)对提高不育剂炔雌醚(Quinestrol)药饵的不育效果,以及改善炔雌醚药饵对鼠类适口性的作用。【方法】试验设3个处理组,分别投喂三组小鼠空白饵料(C组)、炔雌醚药饵(T1组)和DMF-炔雌醚药饵(T2组),计算饵料消耗量。将3个处理组的雄、雌鼠合笼7 d,记录雌鼠怀孕及产仔情况。高效液相色谱法检测不同配制的药饵中炔雌醚的分布浓度。【结果】T1和T2组对雄、雌鼠体重均有显著影响,且T1和T2组雄鼠肾脏器官鲜重分别低于C组16.4%和19.7%。炔雌醚对雌性小鼠繁殖抑制作用明显,T1和T2组雌鼠产仔率降低至C组的37.5%和25.0%,产仔数仅为C组的35.0%和11.1%。DMF对炔雌醚药饵适口性改善作用不明显,高效液相色谱法检测药饵中药物的分布浓度结果表明,T2组的糙米中炔雌醚的含量为T1组的1.5倍;DMF提高了炔雌醚在糙米中的渗透,从而增加了小鼠的药物摄入量。【结论】DMF可快速有效溶解炔雌醚,并增强其在糙米中的渗透力,提高炔雌醚药饵的抗生育作用,有望开发为具有良好应用前景的不育剂配方。

N-methyl-D-aspartate (NMDA) mediates vascular relaxation via nitric oxide (NO) in rats but not in mice

Amperometric studies have indicated that substance P as well as NMDA stimulates release of NO in rat aortic rings. These data have been confirmed by functional observations of vaso-relaxant action of NMDA within noradrenaline pre-contracted aortic rings, supporting the presence of NMDA receptor in rat aortic rings. It is known that the enzyme endothelial NO synthase (eNOS) mediates vasodilatation not only in rats, but also in C57BL6 mice aortic ring, indicating that in this blood vessel NO is the endogenous endothelium-derived vasodilator. In this work, amperometry together with specifically nitrites insensitive micro-biosensors have been applied to examine the effect of NMDA and substance P upon NO release in rat and in two strains of mice aortic rings. The electrochemical data monitored demonstrate that NMDA mediates vascular relaxation via NO in rats but not in mice. These results are supported by functional data, therefore they suggest that NMDA receptors are “not responding” within these experimental conditions in mice aortic rings.

肺炎支原体肺炎患儿外周血及小鼠模型miRNAs差异表达

目的研究miRNAs在肺炎支原体肺炎患儿血中淋巴细胞以及在小鼠感染模型肺组织中的表达差异。方法通过miRNA芯片技术筛选24例肺炎支原体肺炎患儿和24例健康儿童血液淋巴细胞中差异表达的miRNAs,通过实时定量PCR法验证芯片检测结果的准确性,并构建支原体呼吸道感染小鼠模型,通过实时定量PCR法验证小鼠肺组织中相关miRNA的表达差异。结果在支原体肺炎患儿血液淋巴细胞中筛选出表达上调的miRNA 105个,下调的133个(P<0.05),通过PCR进一步证实患儿外周血及小鼠模型肺组织中miR-126、miR-181、miR-146a相对表达升高,miR-155相对表达降低,与芯片结果一致。结论 miR-126、miR-181、2017-12-18接收miR-146a、miR-155在肺炎支原体患儿外周血淋巴细胞及小鼠模型肺组织中存在差异表达,它们可能通过调控炎症因子的释放,参与肺炎支原体导致的免疫炎症反应。

魔芋精粉对MNNG诱发小鼠肺癌的预防作用

取LACA小鼠370只,分为两批,每批又分为正对照(MNNG)、魔芋精粉(R.A.K.)、复合(MNNG+R.A.K.)及空白对照(C)4个组。正对照组每5天于小鼠尾静脉注射MNNG250μg一次,共7次;魔芋精粉组按8％(W/W)魔芋精粉加入92％普通饲料混匀,长期喂养;复合组,在给予MNNG同时,按魔芋精粉组喂养;MNNG组及C组只长期喂普通饲料。实验结果表明,魔芋精粉对MNNG诱发小鼠肺癌可产生不同程度的预防作用,不仅使肿瘤发生数目、每例平均肿瘤数目和小鼠患肿瘤数都大量减少,发癌率从79.75％下降到20.00％,而且延长动物寿命,同时在肿瘤类型构成比上,恶性(腺瘤恶变)减少,无腺癌发生,良性腺癌相对增加。实验结果重复性好,无明显不良作用。

日粮中添加N-氨甲酰-L-谷氨酸及精氨酸对断奶小鼠生长性能的影响

目的:研究日粮中添加N-氨甲酰-L-谷氨酸(NCG)及精氨酸(Arg)对断奶小鼠生长性能的影响。方法:首先通过在日粮中添加0.025%、0.05%、0.1%的NCG,研究NCG对断奶小鼠生长性能的影响。在此基础上,选择同时添加0.05%的NCG和3个水平(0.025%、0.05%、0.1%)的Arg,研究NCG与Arg联合作用对断奶小鼠生长性能的影响。结果:日粮中添加0.1%的NCG,断奶小鼠平均日增质量较对照组提高了12.40%,饲料与体质量比与对照组相比下降了14.65%;同时添加0.05%的NCG和0.025%的Arg,断奶小鼠平均日增质量提高了10.53%。结论:日粮中添加0.1%的NCG能显著提高断奶小鼠生长性能;日粮中同时添加0.05%的NCG和0.025%的Arg,断奶小鼠生长性能也得到显著提高,其提高生长性能的效果与添加0.1%剂量的NCG达到相同水平。

膳食中高n-6/n-3多不饱和脂肪酸比值对小鼠精子浓度及活度的影响

目的近年来男性精子数量、质量呈下降趋势。文中研究小鼠膳食中高n-6/n-3多不饱和脂肪酸比值对其精子浓度及活度的影响。方法健康的B6小鼠20只,随机数表法分成对照组(基础饲料)和实验组(基础饲料+10%花生四烯酸),每组10只。喂食8周后,取各组小鼠附睾尾检测小鼠精子浓度及活度的变化,观察小鼠附睾组织显微结构的改变。结果实验组小鼠血清中α-亚麻酸、二十碳五烯酸、二十二碳六烯酸、二十二碳五烯酸、亚油酸含量均较对照组明显下降(P<0.01),而花生四烯酸和n-6/n-3 PUFAs明显升高(P<0.01)。实验组精子浓度(7×106个/mL)较对照组(80×106个/mL)显著下降,实验组精子活度(27%)较对照组(86%)显著下降,差异有统计学意义(P<0.01)。附睾组织管腔中精子数目明显减少。结论膳食中高n-6/n-3多不饱和脂肪酸比值对精子数量、质量具有显著损伤作用。

n-3多不饱和脂肪酸对NOD小鼠T细胞的免疫调节作用

目的:探讨n-3多不饱和脂肪酸(n-3 poly unsaturated fatty acid,n-3 PUFA)对NOD小鼠T细胞免疫学功能的影响。方法:取野生型Balb/c小鼠和已出现典型的Ⅰ型糖尿病症状的NOD小鼠脾脏细胞,磁珠分选后获得小鼠CD4^+T细胞,将其分为4组:野生型小鼠为Wild type组;NOD小鼠分为未处理组、二十二碳六烯酸(docosahexaenoic acid,DHA)处理组、二十碳五烯酸(eicosapentaenoic acid,EPA)处理组。DHA、EPA处理24 h,PMA和Ionomycin刺激活化后,采用CCK-8法检测T细胞增殖、流式细胞仪检测Th1/Th2极化、ELISA法检测T细胞细胞因子的分泌水平变化。结果:DHA、EPA对T细胞增殖具有显著抑制作用,促进NOD小鼠Th2细胞分化,抑制Th1细胞分化,经ELISA检测,DHA和EPA能够抑制T细胞IL-6、IL-17的分泌。结论:n-3多不饱和脂肪酸通过抑制T细胞增殖,平衡Th1/Th2比例和抑制IL-6、IL-17的分泌,对NOD小鼠的T淋巴细胞起到免疫抑制作用。

N-乙酰半胱氨酸对衰老小鼠抗氧化机能和肠道菌群的影响

本研究旨在探讨N-乙酰半胱氨酸(NAC)对衰老小鼠抗氧化机能和肠道菌群的影响。试验利用D-半乳糖诱致衰老模型小鼠,并通过饮水给小鼠服NAC,测定回肠壁组织中谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量抗氧化指标,采用变性梯度凝胶电泳(DGGE)技术观察小鼠肠道菌群的变化,利用荧光定量PCR测定黏附相关基因表达。结果表明:NAC使衰老小鼠回肠壁组织中GSH-Px、CAT活性显著升高(P<0.05),MDA含量显著降低(P<0.05)。NAC使衰老小鼠肠道乳酸杆菌、双歧杆菌和肠球菌数量增加,大肠杆菌数量减少。NAC使衰老小鼠回肠壁组织三叶因子3(TFF3)、黏液素3(MUC3)基因表达量显著升高(P<0.05)。因此,NAC能提高衰老小鼠抗氧化机能并通过抗氧化能力的调节来影响小鼠肠道菌群,而且NAC调节肠道菌群的机理可能与TFF3和MUC3基因表达有关。

水通道蛋白AQP4基因缺失加重NMDA诱导的小鼠脑损伤

目的:评价水通道蛋白AQP4在兴奋性氨基酸NMDA诱导脑损伤中起的作用。方法:在AQP4基因敲除小鼠,皮层注射NMDA 150 nmol诱导损伤。甲苯胺蓝染色评价损伤面积,Fluro-Jade B染色评价变性神经元,免疫组化法评价血脑屏障通透性增高。结果:与野生型小鼠比较,AQP4基因缺失加重NMDA诱导的皮层损伤,增加损伤区变性神经元密度,加重血脑屏障通透性的增高。结论:AQP4在NMDA诱导的脑损伤中可能起保护作用。

群体感应分子3OC12HSL对小鼠生长、血液和肠道的影响

本研究旨在探讨群体感应分子3OC12HSL对小鼠生长、炎症因子及肠粘膜屏障的影响。采用高剂量盐酸林可霉素灌胃方法建立小鼠腹泻模型,对正常小鼠和腹泻模型小鼠分别灌胃生理盐水、二甲基亚砜(DMSO)、溶于DMSO的3OC12HSL溶液。结果显示,灌胃3OC12HSL降低正常小鼠和腹泻小鼠的增重,提高血清中D-乳酸、TNF-α含量,降低大肠长度及空肠和回肠绒毛长度(P<0.05);腹泻提高血清中IL-1、IL-8、TNF-α含量,降低空肠及回肠绒毛长度(P<0.05);灌胃3OC12HSL和腹泻对回肠绒隐比有协同降低趋势,但差异不显著(P>0.05)。综上,3OC12HSL不利于小鼠的生长,腹泻可能加重3OC12HSL的影响。

由动物实验估算人体内^(13)N-NH-3·H-2O辐射吸收剂量

由小鼠体内分布资料估算N-氨水(13N-NH3?H2O)在人体内辐射吸收剂量,并评价其安全性。由小鼠13尾静脉注射N-NH3?H2O后,在0、0.5、1、2、5、10、20、30min时刻处死动物,测定小鼠体内各脏器放13射性分布,换算至标准人体内分布数据,按MIRD法计算人体内N-NH3?H2O辐射吸收剂量。经估算,人体13肝内照射吸收剂量最高,其值为3.6×10-3mGy/MBq,全身内照射吸收剂量最低,约为1.7×10-3mGy/MBq,其他脏器内照射吸收剂量在(2.4—3.3)×10-3mGy/MBq之间,有效剂量为1.8×10-3mSv/MBq。由小鼠体内分布资料可估算人体内N-NH3?H2O吸收剂量,这些资料为临床安全应用N-NH3?H2O提供了依据。

N-乙酰半胱氨酸对苯再生障碍性贫血小鼠氧化指标的影响观察

目的:初步探讨苯在小鼠体内引起损伤的可能机制以及N-乙酰半胱氨酸(NAC)的保护作用。方法:CD1小鼠50只,随机分成3组,A组10只,为玉米油对照组,单纯皮下注射玉米油4ml/kg,每周3次,共25次;B组20只,每周3次于小鼠背侧皮下注射苯2ml/kg(苯用等量玉米油稀释,均匀混合);C组20只,在皮下注射苯的基础上同时口服NAC,按400mg·kg-1·d-1给予。分别处理各组小鼠并检测相关指标。结果:①B、C组与A组比较外周血WBC、Hb、Ret等指标显著降低;②C组与B组比较,除PLT无显著性差异外,WBC、Hb、Ret均有明显改善,均P<0.05,提示NAC对苯的血液学毒性有一定的预防作用;③与A组比较,B、C组各氧化指标均显著增高,其中B组与A组比较活性氧、丙二醛(MDA)、超氧化物岐化酶(SOD)、过氧化氢酶(CAT)均P<0.01,总抗氧化物(T-AOC)P<0.05,GSH含量无明显变化,巯基(-SH)下降P<0.01;C组与A组相比活性氧P<0.05、MDA、SOD、CAT均P<0.01,T-AOCP<0.05,还原型谷胱甘肽(GSH)含量升高,P<0.01,-SH含量无显著变化;④C组与B组相比各氧化指标均显著降低,活性氧、MDA、SOD、CAT均P<0.01、T-AOCP<0.05。结论:①苯诱发小鼠造血损伤的机制中有氧化损伤作用的参与;②NAC在小鼠体内一定程度上减轻了苯的血液学毒性,其中NAC的抗氧化作用是一个重要因素。