冷暴露对小鼠肝脏内质网应激和内源性凋亡的影响

将5周龄体质量为23～25 g的C57BL/6型雄性小鼠随机分为室温对照组和冷暴露组。室温对照组小鼠刺激条件为温度(24±2)℃,湿度40%;冷暴露组小鼠饲养于人工智能气候室内,刺激条件为温度(4±1)℃,湿度40%,每天冷暴露3 h,连续暴露3周。通过HE染色、Masson染色、透射电镜观察肝脏组织的生理结构;Western blot技术检测肝脏组织内质网应激标志蛋白CHOP、GRP78、XBP1的表达,以及内源性凋亡标志蛋白Caspase-3、Cyt C、Bax、Bcl-2的表达水平。结果显示,与对照组相比,冷暴露组小鼠肝细胞发生轻微水样变性,可见炎性细胞浸润,肝小叶结构异常;细胞间质可见轻微的胶原纤维沉积;内质网、线粒体发生轻微损伤;GRP78、XBP1、CHOP表达水平显著升高(P<0.05);Cyt C表达水平、Bax/Bcl-2的比值、活化的Caspase-3与其Caspase-3前体的比值显著升高(P<0.01)。结果表明,冷暴露能够诱导小鼠肝脏组织发生内质网应激,导致内源性凋亡的发生。     

大鼠急性冷应激模型的建立

通过分析冷刺激对大鼠血清中细胞因子、皮质酮(CORT)、促肾上腺皮质激素(ACTH)的含量以及外周血淋巴细胞中热休克蛋白70(Hsp70)表达量的影响,构建大鼠急性冷应激模型,旨在为其相关研究提供研究基础。本试验急性冷刺激时间为12h。利用ELISA方法检测各组大鼠血清中IL-2、IL-4、IL-6、IL-10、TNF-α、CORT、ACTH的含量;采用Western blot和qRT-PCR方法检测各组大鼠外周血淋巴细胞中HSP70及mRNA表达量。结果表明,与对照组相比,急性冷刺激组大鼠血清中IL-2和ACTH的含量显著升高(P0.05),IL-4、IL-6、TNF-α和CORT的含量极显著升高(P0.01),IL-10无显著变化(P0.05);外周血淋巴细胞内HSP70及其mRNA表达量呈显著升高水平(P0.05)。成功构建大鼠急性冷应激模型。     

复方中药制剂提高大鼠抗冷应激作用时效关系的研究

本研究选用健康成年 Wistar大鼠 18只 ,随机分为 2组 ,每组 9只 ,分别用待选中药配方、蒸馏水灌胃 ,在第 1天、第 2天和第 5天给药后 2 h,进行冷水 (水温 10℃ )游泳 ,观察各组游泳时间。结果表明 :第 1天、第 2天实验组游泳时间与对照组相比无显著差异 ,第 5天实验组游泳时间显著长于对照组 (P<0 .0 1) ;透射电镜观察发现 ,实验组肾上腺皮质束状带细胞内脂滴比对照组内脂滴少 ,对照组细胞基质出现空泡样变化。提示 :该中药配方服用 5 d后能提高机体抗冷应激原能力 ,减轻寒冷应激对机体造成的损伤     

冷应激大鼠肾上腺组织形态结构变化的研究

以大鼠为试验对象，研究冷应激情况下肾上腺组织结构的变化。结果表明：应激后大鼠肾上腺皮质束状带和网状带宽度显著增高．且分界明显。应激后束状带和髓质细胞数目显著高于常温对照组。球状带细胞数目增多．出现分裂情况；束状带细胞有脱颗粒现象，使细胞呈空泡状；网状带细胞胞质内脂质颗粒少，细胞小；髓质细胞体积增大，胞核大且密集，胞浆染色深。     

冷应激对猪脂肪、肝脏组织中细胞因子信号转导抑制因子3 mRNA表达的影响

试验选用30头"军牧1号"猪,随机分成5组,包括常温对照组和4个冷应激组。常温组在21 ℃±2 ℃饲养,冷应激组的温度设置分别为:-10 ℃±2 ℃、-5 ℃±2 ℃、0 ℃±2 ℃、5 ℃±2 ℃。冷应激2 h屠宰后采集腹腔脂肪、颈部皮下脂肪、胸部皮下脂肪和肝脏组织样品,通过荧光定量PCR方法检测细胞因子信号转导抑制因子3(suppressor of cytokine signaling 3,SOCS3)的mRNA的表达量,初步探讨冷应激对猪脂肪及肝脏组织中SOCS3 mRNA表达量的影响。试验结果显示,冷应激猪SOCS3在腹腔脂肪、颈部皮下脂肪、胸部皮下脂肪和肝脏组织中,随着温度的降低,表达量逐渐升高,且总体差异显著(P＜0.05)。试验结果表明,SOCS3受到冷应激的影响,在不同脂肪组织部位发生了变化,可能参加了脂肪细胞因子的调控,从而改变脂肪组织分布及脂肪代谢平衡,为研究冷应激对机体的影响及作用机制奠定了试验依据和理论基础。     

急性冷刺激对大鼠骨骼肌和7个内脏器官的组织结构影响

冷刺激是北方寒区常见的应激原,可对机体多个内脏器官组织学结构产生影响。本试验采用病理学观察方法,研究急性冷刺激处理对大鼠骨骼肌和7个内脏器官的组织结构影响。将10只Wistar大鼠随机均分为对照组和冷刺激组。对照组在(24.0±0.1)℃温度下饲养;冷应激温度为(4.0±0.1)℃,冷刺激时间为12h。冷刺激后,采集两组大鼠骨骼肌、心脏、脾脏、肝脏、肾脏、胃、十二指肠及肺脏8种样品,制作成组织切片,镜下观察。结果显示,急性冷刺激对大鼠骨骼肌、心肌、胃壁黏膜及肾脏均有不同程度的损伤;肝脏、十二指肠组织结构未见病理变化;脾脏可见淋巴小结体积增大,反应性增生。结果表明,急性冷应激可造成大鼠机体骨骼肌及内脏损伤,但免疫功能增强。     

应激宁对大鼠应激性损伤中氧自由基变化的影响

将揭示应激损伤对氧自由基的变化影响及应激宁的保护效应,采用束缚浸水３ｈ的应激方法,建立大鼠应激性损伤模型,测定血浆,胃,肝,心组织中ＳＯＤ,ＭＤＡ的水平,结果应激组和应激宁组与对照组相比较,ＳＯＤ的活性明显下降,ＭＤＡ含量明显升高（Ｐ〈０．０１）,而且应激宁组与应激组相比较,ＳＯＤ活性明显升高,ＭＤＡ的含量明显下降（Ｐ〈０．０１或Ｐ〈０．０５）,提示氧自由基可能是应激性损伤的介导因素,应激宁对应激     

冷应激对雏鸡沙门氏杆菌感染的影响初报

为了观察冷应激对雏鸡白痢的影响，实验选用200只雄性海兰雏鸡进行沙门氏杆菌攻毒感染实验，攻毒后对其进行急性（12h以内）冷应激（比正常湿度低10℃）。结果表明：1亿－20亿个活菌可使雏鸡全部感染，但无死亡，12h冷应激对感染无明显影响。结果提示低10℃的12h以内低温刺激对雏鸡的抗病力无不良影响。     

应激宁对大鼠应激性溃疡中三种激素水平的影响

采用束缚浸水法建立大鼠应激性溃疡模型,探讨了胃泌素、胰高血糖素、血栓纱Ｂ２（ＴＸＢ２）的变化与与应激性溃疡相关性及应激宁的抑制效应。结果表明,应激组血浆、胃组织的３处激素水平的均极显著的高于对照组,应激＋应激宁组与应激组相比较,３处激素的水平极显著或显著降低,或降低不显著,提示这３种激素可能从不同角度参与应激性溃疡的形成,同时,应激宁对应激性溃疡的形成具有抑制作用。     

冷应激对猪生产性能的影响

低温环境显著改变猪的体组织的组成、代谢和生产性能,使之有别于适温区和热应激。我国大部分地区寒冷季节漫长,猪舍一般都缺乏加温设备或保温不足,致使猪群或长或短地处于冷应激状态。养猪生产者应该了解冷应激对猪群的影响,才能有效地应对低温对养猪生产造成的损害。为此,本文对研究相对少见的低温对猪群的影响这一主题进行综述。临界温度是指适温区的下限。当环境温度低于临界温度时,猪处于冷应激状态。因为部分摄食被用于产热来调节体温,所以,低温条件下养猪生产不能优化。此外,在冷应激情况下,猪群可能还要面对更多的健康问题。下表给出…     

一副蒙药复方对急性冷应激小鼠非特异性免疫水平的影响

为了研究抗冷应激蒙药复方对急性冷应激小鼠非特异性免疫的影响,试验将昆明系小鼠随机分为冷应激组、阳性对照组、蒙药高剂量组、蒙药低剂量组,在6℃条件下冷应激0 h、2 h、24 h后从每组随机取8只小鼠称重,进行腹腔吞噬试验及脾脏自然杀伤(NK)细胞活性试验,并取胸腺、脾脏称重。结果表明:冷应激2 h、24 h,蒙药高剂量组小鼠胸腺指数极显著高于冷应激组(P<0.01);冷应激24 h,蒙药高、低剂量组小鼠脾脏指数略高于冷应激组(P>0.05);蒙药高、低剂量组小鼠吞噬指数和吞噬百分率在2,24小时均显著或极显著高于冷应激组(P<0.05或P<0.01);蒙药高、低剂量组NK细胞活性在2,24小时时均显著或极显著高于冷应激组(P<0.05或P<0.01)。说明蒙药复方可以提高6℃条件下急性冷应激小鼠的非特异性免疫水平。     

Effect of acute deficiency of dietary proline on proline balance in the rat small intestine and liver

Introduction Proline is widely found in all types of mammalian tissue, and accounts for about 20% of the amino acids that constitute collagen (A dams 1970). Proline is nutritionally nonessential but biologically it is an important amino acid and consequently mammalian organisms synthesize the required amounts of proline even in the absence of sufficient proline consumption via food. The metabolism of higher animals is unique, and amino acid metabolism differs from one tissue to the next. Some organs are capable of synthesizing nonessential amino acids for use throughout the body. For example, arginine is primarily synthesized in the kidney and then released and distributed throughout the body. Pyrroline-5-carboxylate reductase is the enzyme responsible for the final stage of proline synthesis, and its activity has been confirmed in many important organs and tissue such as the cartilage, liver, small intestine, kidney and thymus gland (H erzfeld et al. 1977; S mith and P hang 1978). However, the different levels of pyrroline-5-carboxylate reductase activity among these organs has led to the belief that different amounts of proline are synthesized in these organs. In order to ascertain biological responses to dietary proline deficiency, it is important to identify the organs that release and distribute proline throughout the body when insufficient proline is consumed through the diet, thus reducing the blood proline concentration. Few studies have investigated this issue, but when ascertaining biological responses to dietary proline deficiency, it is more important to elucidate the effect of dietary proline deficiency on the metabolism of proline and other amino acids that are closely related metabolically to proline, in proline synthesizing organs. One of the most effective ways to assess amino acid metabolism in a target tissue of higher animals is to measure the difference between the arterial and venous concentrations of amino acids. I shikawa (1974) measured arteriovenous differences in order to examine the release of proline from the kidney and small intestine of fasted rats and the uptake of proline by the liver. In a previous study, it was found that when the plasma proline concentration was reduced to the fasting level by the consumption of a proline-deficient diet, proline was released from the kidney (W atanabe et al. 1995, 1997). In the present study, to ensure the induction of dietary proline deficiency, a completely purified diet containing all amino acids except for proline was prepared and fed to rats under experimental conditions. To investigate the role of the small intestine and liver in supplying and ingesting proline when the uptake of proline through food is restricted, the release and uptake of amino acids in the small intestine and liver were assessed by measuring carotid artery–portal vein and portal–hepatic vein differences in proline in rats.     

低温胁迫对墨西哥玉米幼苗抗寒性的影响

在5和15℃低温胁迫下,对墨西哥玉米Zea mexicana的2种新材料玉米草1号和玉米草2号叶片内部与抗寒性有关的某些生理生化指标在处理6、24、487、2 h后的变化进行了研究。比较了不同低温处理下,不同材料生理指标变化情况,通过变化规律分析2种材料的抗寒性大小。结果表明,从3个生理指标上看,随温度降低,玉米草1号能保持更好的细胞膜完整性和更低的丙二醛含量,并诱导产生更多的脯氨酸,说明玉米草1号比玉米草2号具有更强的耐寒性。     

益生菌和葡聚糖对冷应激状态下贵妃雏鸡血液学变化的影响

选择1日龄健康贵妃雏鸡192只,随机分为16组,每组12只。试验雏鸡经受比正常温度低10℃的急、慢性冷应激和冷适应处理,并对急性冷应激组添加益生菌、慢性冷应激和冷适应组添加葡聚糖处理。翼下采血制血涂片,镜检观察雏鸡白细胞分类变化,并用血细胞分析仪测定血相变化与之对比分析。结果表明,在急性冷应激期间,雏鸡的白细胞分类计数波动变化明显,嗜碱粒细胞数目和H/L比值都明显增加;血红蛋白、红细胞以及血小板数目显著增加。冷适应后淋巴细胞数目明显增加,嗜中性粒细胞明显减少,H/L比值下降。益生菌、葡聚糖处理对白细胞总数和嗜酸粒细胞影响明显,益生菌处理24h明显增加白细胞数量,葡聚糖处理15d降低了嗜酸粒细胞数目。本试验结果提示急性冷应激能引起雏鸡血液学参数的明显波动,贵妃雏鸡抗冷应激能力较强,而益生菌、葡聚糖能提高雏鸡适应冷应激的能力,改善应激状态下的免疫功能。     

α-酮戊二酸对免疫应激下断奶仔猪肝损伤的影响

24头体质量为(7.25±1.13)kg的(21±1)日龄(杜×长×大)断奶仔猪随机分为3组,每个组设有8个重复,每个重复1头猪。3个组分别为:饲喂基础日粮,注射生理盐水(对照组);饲喂基础日粮,注射脂多糖(LPS)(LPS组);饲喂基础日粮+1%α-酮戊二酸(AKG),注射LPS(AKG组)。预试期7d,正式试验期16d,探讨AKG对免疫应激下断奶仔猪肝损伤的影响。结果显示:(1)LPS刺激导致血清腺苷脱氨酶(ADA)的活性显著升高了15.29%(P0.05),日粮添加1%AKG血清ADA活性较LPS组降低了7.85%(P0.05);(2)LPS刺激导致肝脏丙二醛(MDA)活性显著升高了59.61%(P0.05)以及谷胱甘肽过氧化物酶(GSH-Px)活性显著降低了23.21%(P0.05),而日粮添加1%AKG肝脏MDA活性较LPS组降低了13.70%(P0.05)、GSH-Px活性则升高了17.16%(P0.05);(3)LPS刺激导致肝脏总蛋白质含量和RNA/DNA比值分别显著增加了8.20%(P0.05),10%(P0.05),而日粮添加1%AKG较LPS组肝脏总蛋白质含量和RNA/DNA比值分别降低了3.94%(P0.05),10%(P0.05)。结果表明:AKG能在一定程度上缓解LPS刺激对断奶仔猪肝脏的损伤。     

钒对大鼠肝脏生长及结构的影响

为探讨微量元素钒对大鼠肝脏生长发育的影响,150只大鼠随机分成5组,每组30只,雌雄各半,试验组分别饮用添加不同剂量钒的饮水(10,20,40,60 mg/kg),对照组饮饲蒸馏水,于饮饲后2,4,6,8,10周断脊处死,取肝脏测质量并制作石蜡、超薄切片,光学、电子显微镜观察,显微摄影.结果显示,试验Ⅰ组(10 mg/kg)、试验Ⅱ组(20mg/kg)、试验Ⅲ组(40 mg/kg)大鼠肝脏质量较对照组增加,其中试验Ⅱ组增加显著(P＜0.05),而试验Ⅳ组(60mg/kg)较对照组肝脏质量减轻.显微观察可见,试验Ⅰ、Ⅱ组肝脏组织结构清晰,肝细胞大而圆;验Ⅲ组肝细胞有脱落现象且轻度水肿;验Ⅳ组肝脏质量与同一对照组相比减小,肝细胞界限不清晰且水肿、颗粒及脂肪变性严重.试验Ⅰ、Ⅱ、Ⅲ组超微观察可见,肝细胞内线粒体和内质网结构正常;验Ⅳ组肝细胞内线粒体和内质网断裂、溶解、肿胀.结果表明,大鼠饮水中添加40 mg/kg以下剂量的钒对大鼠是安全的,饮饲60 mg/kg钒对大鼠肝脏有毒害作用.     

Effect of acute heat stress on heat shock protein 70 messenger RNA and on heat shock protein expression in the liver of broilers

1. The synthesis of heat shock protein 70 (Hsp70) mRNA and the expression of Hsp70 in the liver of broiler chickens submitted to acute heat stress (35°C for 5 h) was investigated.

2. Hsp70 expression was detected by SDS‐PAGE and Western blot analysis using a polyclonal antiserum against Hsp70 of Blastocladiella emersonii. The specific signal of Hsp70 mRNA was analysed by Northern blot using as probe a Hsp70 cDNA of B. emersonii.

3. An increase in the amount of Hsp70 was detected from the first up to the fifth hour of acute heat exposure. This increase in the amount of Hsp70 was accompanied by an increase in Hsp70 mRNA which peaked at 3 h.

4. This study shows that the heat induced increase in Hsp70 mRNA and protein in broiler liver, in vivo, are time dependent, similar to that in mammals.     

Ruminant cold stress: effect on production

A review is presented of biological issues and practical consequences of the effects of cold stress on ruminant animals. When animals are subjected to extreme cold stress, substantial dietary energy may be diverted from productive functions to the generation of body heat. Failure to produce sufficient heat can result in death. More often, however, cold stress leads to the development of secondary changes and possibly disease. With prolonged exposure to even mildly cold conditions, physiological adaptation occurs in animals resulting in increases in thermal insulation, appetite and basal metabolic intensity, as well as alterations in digestive functions. Much of the reduced productivity, and in particular the reduced nutritional efficiency, observed in ruminant production systems during the colder part of the year, can be accounted for by these adaptive changes.