马齿苋多糖对暴发性肝功能衰竭小鼠肠道菌群及血清TNF-α、HGF、血内毒素影响的研究

目的 研究马齿苋多糖对暴发性肝功能衰竭小鼠肠道菌群及血清TNF-α、HGF、血内毒素含量的影响,探讨中药微生态调节剂对暴发性肝功能衰竭的调节机制.方法 应用D-氨基半乳糖、脂多糖腹腔注射建立暴发性肝功能衰竭小鼠模型,然后用马齿苋多糖进行治疗,同时设正常对照组、阴性对照组,于给药14 d后处死小鼠,进行血清TNF-α、HGF及血内毒素含量检测.结果 D-氨基半乳糖、脂多糖腹腔注射后,小鼠肠道菌群失调、血清TNF-α、HGF及血内毒素含量增加.用马齿笕多糖治疗14 d后血清TNF-α、血内毒素含量降低,HGF升高.结论 马齿笕多糖可调整暴发性肝功能衰竭小鼠肠道菌群失调、减少肠源性内毒素的产生、减轻血浆炎性细胞因子表达、增加HGF,从而减轻肠源性内毒素血症对肝脏的损害,能改善小鼠肝功能.     

微生态调节剂—乳果糖对肝损伤和内毒素血症防护效果的研究

本文研究了乳果糖口服对急性肝损害的防治效果。发现：（１）乳果糖灌服可迅速减少正常大白鼠门脉血中的内毒素。（２）给用Ｄ－氨基半乳糖破坏肝脏,乳果糖做预防性及治疗性口服,可明显地保护肝细胞及减轻内毒素血症并减轻肝组织损害。（３）首创了一种暴发性肝衰竭模型,即用内毒素叠加Ｄ－氨基半乳糖致小鼠肝衰竭模型。其肝脏损害速度与程度及２４小时死亡率远大于单用上述二种中毒成分之一。用乳果糖口服可明显预防此种暴发性肝     

特异性卵黄抗体(IgY)对小鼠内毒素血症的保护作用

目的:研究特异性卵黄抗体(Egg yolk immunoglobulin,IgY)对小鼠内毒素血症的保护作用.方法:以灭活的E.coli O111免疫产蛋母鸡制备特异性IgY抗体.ELISA法检测对E-coli O111及内毒素(Lipopolysaecharide,LPS)的结合活性.腹腔注射LPS(2mg/m1),0.1 ml/10g体重,建立小鼠内毒素血症模型.小鼠随机分为5组,分别给药保护:空白组(生理盐水)、阴性对照组(非特异性IgY,20mg/ml)、阳性对照组(头孢哌酮钠,20mg/ml)、高剂量组(特异性IgY,40mg/m1),低剂量组(特异性IgY,20mg/ml).给药剂量为:攻毒前,0.15 ml/l0 g体重,24 h一次,共两次;攻毒后,0.25 ml/10 g体重,24 h一次,共7次.观察小鼠一般情况,体重变化,外周血中白细胞(WBC)和血小板(PLT)数的变化及各组小鼠的死亡率.结果:特异性IgY与E.coli O111及LPS均有体外结合活性.LPS感染后,各组小鼠外周血中WBC和PLl均有不同程度的下降,体重下降.特异性抗体保护组各指标较快恢复到正常水平,其他组恢复缓慢.各组小鼠七天内死亡率分别为:空白组,100%;阴性对照组,85%;阳性对照组,30%;低济量组,30%;高剂量组,0%.结论:特异性IgY对内毒素血症小鼠有保护作用.     

抗炭疽人源化单抗在炭疽芽孢致死小鼠模型中的治疗效力评价

目的:建立炭疽芽孢(疫苗株A16R)攻击DBA/2J小鼠的致死模型,并使用该模型评价抗炭疽人源化单抗5E11的治疗效力。方法:用不同剂量A16R芽孢背部皮下攻击小鼠,计算半数致死剂量(LD_(50));ELISA定量检测5E11在小鼠体内的药代动力学参数;用100倍LD_(50)的芽孢攻击小鼠,攻毒后不同时间用不同剂量的5E11单抗治疗小鼠,观察小鼠存活等情况。结果:A16R芽孢攻击DBA/2J小鼠的LD50为7.8×10～3CFU;5E11在小鼠体内的平均消除半衰期约为7 d;攻毒后1 d给药的几个剂量组能够完全保护,攻毒后2～3 d给药能够提供40%～80%的保护。结论:抗炭疽人源化单抗5E11在芽孢攻击致死小鼠模型中表现出良好的保护效果,具有紧急治疗炭疽芽孢感染导致的急性炭疽的潜力。     

微生态调节剂－乳果糖对肝损伤和内毒素血症防护效果的研究

本文研究了乳果糖口服对急性肝损害的防治效果。发现：（１）乳果糖灌服可迅速减少正常大白鼠门脉血中的内毒素。（２）给用Ｄ－氨基半乳糖破坏肝脏,乳果糖做预防性及治疗性口服,可明显地保护肝细胞及减轻内毒素血症并减轻肝组织损害。（３）首创了一种暴发性肝衰竭模型,即用内毒素叠加Ｄ－氨基半乳糖致小鼠肝衰竭模型。其肝脏损害速度与程度及２４小时死亡率远大于单用上述二种中毒成分之一。用乳果糖口服可明显预防此种暴发性肝坏死之发生,但用乳果糖腹腔注射则毫无保护作用。乳果糖只经口服通过对肠道菌群的调整才有降低内毒素血症效果。（４）用ｓｈｗａｒｔｚｍａｎ反应证明乳果糖对内毒素的生物活性没有阻断或抑制作用。本文证明乳果糖对Ｇａｌ－Ｎ致肝坏死的保护作用,并经临床观察证明对肝脏病人内毒素血症的治疗效果。     

益母草注射液小鼠急性毒性和Beagle犬重复给药毒性试验研究

通过小鼠单次给药急性毒性试验和Beagle犬重复给药毒性试验,评价益母草注射液(YMC)的安全性。用半数致死剂量法对小鼠进行急性毒性试验,观察小鼠的死亡情况和急性毒性症状,用Bills法计算半致死剂量(LD50)。将32只Beagle犬根据体质量、性别随机分为YMC 240.99 mg·kg~(-1)、120.50 mg·kg~(-1)、60.25 mg·kg~(-1)组和0.9%氯化钠注射液对照组,每组8只。静脉滴注给药,每周给药6 d,连续180 d,停药恢复30 d。对Beagle犬进行临床症状、体质量、心电图、血液学、血液生化学、血清电解质、尿液及组织病理学等检查。YMC小鼠静脉给药LD50为845.64 mg·kg~(-1),急性毒性症状主要表现为跳跃、烦躁、嗜睡、活动减少、阵挛性抽搐、眼球突出、尿失禁。重复给药毒性试验,Beagle犬出现呈剂量反应趋势的流涎、呕吐症状,未见肝、肾毒性,其余各项检测指标也均未见与药物毒性相关的明显异常。YMC小鼠静脉给药LD50相当于临床拟用剂量的394.6倍,YMC重复给药毒性试验对Beagle犬的安全剂量为120.50 mg·kg~(-1),相当于临床拟用剂量的56.2倍。提示YMC具有较高的安全性。     

5-氟尿嘧啶诱导小鼠化疗性肠黏膜炎模型的建立

目的研究5-氟尿嘧啶(5-fluorouracil,5-FU)诱导小鼠化疗性肠黏膜炎动物模型。方法采用不同剂量的5-FU单次或连续5 d腹腔注射给予小鼠,每日观察小鼠体重、腹泻情况,并分别于末次给药后72 h或24 h,观察小鼠外周血象及小肠组织病理形态学改变。结果与正常组比较,单次或连续5 d给予5-FU后,各剂量组小鼠出现不同程度的腹泻及体重降低,外周血象白细胞和血小板水平明显降低(P0.05或P0.01),其中单次给药400 mg/kg组、连续给药50,100 mg/kg组出现明显的肠黏膜炎病理特征,100 mg/kg组剂量过高,死亡率达100%。结论单次或连续5 d给予5-FU诱导小鼠肠黏膜炎的作用呈剂量相关性,其中单次给药以400 mg/kg为合适剂量,连续5 d给药以50 mg/kg为合适剂量。     

菟丝子总黄酮对内分泌衰退痴呆模型小鼠学习记忆功能的影响及保护作用机制

目的:研究菟丝子总黄酮对内分泌衰退痴呆模型小鼠学习记忆功能的影响,并探讨其可能的作用机制。方法:将50只昆明种雌性小鼠随机分为模型组,雌激素对照组(0.3 mg·kg-1),菟丝子总黄酮低剂量组(35mg·kg-1),菟丝子总黄酮中剂量组(70 mg·kg-1)和菟丝子总黄酮高剂量组(140 mg·kg-1),采用背部去卵巢法切除双侧卵巢,另取10只小鼠作为假手术对照组,建立内分泌衰退小鼠模型,术后各治疗组进行灌胃给药治疗三个月,假手术组和模型组均给予0.9%生理盐水。给药结束后采用Morris水迷宫观察小鼠行为学变化;放射免疫法检测小鼠血液中雌激素的水平;HE染色光镜观察海马神经元病理形态;流式细胞仪检测小鼠海马神经细胞凋亡率和免疫印迹法检测海马区神经细胞凋亡相关蛋白(Bcl-2、Bax、Csapase-3)及Cyt-c蛋白的表达水平。结果:与假手术组相比,模型组小鼠学习记忆能力明显下降(P0.01);血液中雌激素水平显著降低(P0.01);海马神经细胞凋亡率显著增加(P0.01);Cyt-c、Caspase-3、Bax蛋白表达水平大大增加(P0.01),Bcl-2蛋白表达降低明显(P0.01)。与模型组相比,TFSC各治疗组小鼠学习记忆能力显著增强(P0.05,P0.01,P0.01);血液中雌激素水平上升显著(P0.05,P0.01,P0.01);小鼠海马区神经细胞凋亡率明显下降(P0.05,P0.01,P0.01);同时Cyt-c、Caspase-3、Bax蛋白表达水平均大大降低,Bcl-2蛋白表达均明显增加(P0.05,P0.05,P0.01)。结论:TFSC可上调脑细胞中Bcl-2蛋白的表达水平,抑制Bax、Caspase-3和Cyt-c蛋白的表达量,进而增强神经元的可塑性和营养性,以防止神经细胞从内源性线粒体途径丢失或凋亡,进一步改善内分泌衰退型痴呆小鼠的学习记忆能力。TFSC可能是通过促进或增强下丘脑-脑垂体-性腺轴功能,从而达到增加雌激素水平和改善内分泌系统功能的目的。     

链脲佐菌素诱导SD和Wistar大鼠糖尿病模型的影响因素

目的通过注射链脲佐菌素（STZ）制作SD和Wistar大鼠糖尿病模型,观察大鼠品系、给药剂量、给药次数对大鼠成模率、死亡率的影响,同时研究利用口服葡萄糖耐量试验（OGTT）判断大鼠糖尿病成模率的意义。方法设置共同的正常对照组,①Wistar大鼠随机分为中剂量组（55 mg/kg）和高剂量组（65 mg/kg）;②SD大鼠一次性腹腔注射STZ（55 mg/kg）,与①中的Wistar大鼠作对比;③SD大鼠随机分为一次给药组和两次给药组,注射剂量均为55 mg/kg,观察期间进行OGTT。结果①Wistar大鼠成模率和死亡率均高于SD大鼠;②采用SD大鼠、中剂量给药和两次给药的方式可提高成模率,并降低死亡率;③在有明确胰岛病理改变的模型组大鼠,其OGTT异常阳性率显著高于空腹血糖异常阳性率。结论用STZ诱导糖尿病模型是一种稳定可靠的方法。Wistar大鼠成模率和死亡率均高于SD大鼠;选用中剂量给药及两次给药的方式可提高SD大鼠成模率,并降低死亡率,维持时间较长。在动物实验中OGTT比空腹血糖监测更有诊断意义,不易造成漏诊。     

枯草芽孢杆菌BS-Z15代谢产物治疗白色念珠菌感染昆明小鼠的作用

本文就枯草芽孢杆菌BS-Z15发酵液中粗提的代谢产物(metabolites extracted from fermentation broth, MEs)对白色念珠菌的抑制作用进行了研究,并探讨了该提取物治疗感染白色念珠菌的昆明小鼠的作用。根据《产孢丝状真菌液基稀释法抗真菌药物敏感性试验方案》测定了MEs的最小抑菌浓度(MIC),进一步在建立小鼠白色念珠菌感染模型基础上,以氟康唑(90 mg/kg)为阳性药物对照组,以生理盐水为模型对照组,以MEs高剂量(90 mg/kg)、MEs中剂量(60 mg/kg)、MEs低剂量(30 mg/kg)为实验组,采用灌胃给药法处理,以一般状况、体重、死亡率,肝脾病变程度、血清中总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量变化为评价指标,分析MEs对小鼠白色念珠菌感染模型的治疗作用。结果表明,MEs对白色念珠菌的MIC为0.33 mg/mL,MEs可使酵母态白色念珠菌菌体表面凹陷致死。与模型组比较,MEs高剂量治疗小鼠表现出更好的生理状态,肝脾的损伤程度明显改善,死亡率显著降低,血清中的总抗氧化活性及SOD活性显著增加、MDA含量显著下降。比较MEs不同剂量处理的小鼠,表明治疗效果在一定浓度范围内与剂量成正相关性。说明枯草芽孢杆菌BS-Z15代谢产物对感染白色念珠菌的小鼠有一定的疗效,具有潜在的治疗白色念珠菌真菌病的药用价值。     

Experimental studies on the bacterial product CANTASTIM derived from Pseudomonas aeruginosa. V. Protective effect in endotoxin shock

In this paper, we investigated the effect of the treatment with the bacterial immunomodulator CANTASTIM in a model of endotoxin shock in mice. Among the different mouse models described for septic shock, we have chosen the low-dose endotoxin model using D-galactosamine sensitized mice. We noticed a significant increase in the survival rate of the mice treated with CANTASTIM before the endotoxin challenge. This protective effect was correlated with a strong reduction in the level of TNF alpha in the sera of treated mice. Prior exposure to CANTASTIM also attenuated subsequent ex vivo nitric oxide production by peritoneal macrophages of the mice. In this model of endotoxin shock, the major role has been attributed to TNF alpha acting through its receptor TNFRI (p55). A downregulation of this receptor as a consequence of the treatment with CANTASTIM may be hypothesized. However, the intervention of CANTASTIM in other points in the cytokine network involved in endotoxin shock cannot be excluded.     

Flavonoids protect mice from two types of lethal shock induced by endotoxin

The protective effect of flavonoids on two types of lethal endotoxic shock was studied. A lethal endotoxic shock was induced by administration of lipopolysaccharide (LPS) into D-galactosamine (D-GalN)-sensitized mice and another one was done by administration of a high dose of LPS into normal mice. Pretreatment with a series of flavonoids protected mice from two types of endotoxin lethality. Flavonoid pretreatment reduced the serum tumor necrosis factor-alpha (TNF-alpha) level in mice injected with D-GalN and LPS, but not in mice injected with a high dose of LPS. TNF-alpha-induced lethal shock in D-GalN-sensitized mice was also protected by pretreatment with flavonoids, suggesting that flavonoids augmented the resistance to TNF-alpha lethality. On the other hand, flavonoids reduced the plasma level of lipid peroxides in mice injected with a high dose of LPS, but not in D-GalN-sensitized mice. Taken together, these results indicated that flavonoids might protect mice from two types of endotoxin lethality. The protective mechanism of flavonoids in each endotoxin lethality is discussed.     

Investigation of protective properties of Shigella sonnei carbohydrate biopolymers under experimental endotoxic shock models

We studied tolerogenic properties of new nonpyrogenic low-endotoxic complex preparation composed of Shigella sonnei carbohydrate biopolymers under D-galactosamine and direct experimental endotoxic shock models. Pretreatment with complex preparation (exopolysaccharide + lipopolysaccharide) S. sonnei protects mice (CBA × C57B1/6)F1 against lipopolysaccharide (E. coli O:55)-mediated death. We demonstrate correlation between increasing preimmunization dose of complex preparation with rate of survival and reduction of TNF-α serum level under a direct endotoxic shock model.     

Lipopolysaccharide and D-galactosamine-induced hepatic injury is mediated by TNF-alpha and not by Fas ligand

Tumor necrosis factor (TNF)-alpha and Fas ligand (FasL) are trimeric proteins that induce apoptosis through similar caspase-dependent pathways. Hepatocytes are particularly sensitive to inflammation-induced programmed cell death, although the contribution of TNF-alpha and/or FasL to this injury response is still unclear. Here, we report that D-galactosamine and lipopolysaccharide-induced liver injury in C57BL/6 mice is associated with increased hepatic expression of both TNF-alpha and FasL mRNA. Pretreatment of mice with a TNF-binding protein improved survival, reduced plasma aspartate aminotransferase concentrations, and attenuated the apoptotic liver injury, as determined histologically and by in situ 3' OH end labeling of fragmented nuclear DNA. In contrast, pretreatment of mice with a murine-soluble Fas fusion protein (Fasfp) had only minimal effect on survival, and apoptotic liver injury was either unaffected or exacerbated depending on the dose of Fasfp employed. Similarly, mice with a spontaneous mutation in FasL (B6Smn.C3H-Fasl(gld) derived from C57BL/6) were equally sensitive to D-galactosamine/lipopolysaccharide-induced shock. We conclude that the shock and apoptotic liver injury after D-galactosamine/lipopolysaccharide treatment are due primarily to TNF-alpha release, whereas increased FasL expression appears to contribute little to the mortality and hepatic injury.     

Reduced lipopolysaccharide (LPS)-induced nitric oxide production in peritoneal macrophages and inhibited LPS-induced lethal shock in mice by a sugar cane (Saccharum officinarum L.) extract

A sugar cane extract (SCE) has been found to have an immunostimulating effect in several animals. Lipopolysaccharide (LPS) is known to induce endotoxin shock via the production of inflammatory modulators such as tumor necrosis factor (TNF)-alpha and nitric oxide (NO). We examined in the present study the effects of SCE on the TNF-alpha and NO production in LPS-stimulated mice peritoneal cells and the endotoxin shock in mice. The supplementation of SCE to peritoneal macrophages cultured with LPS resulted in a significant decrease in NO production. All the mice injected intraperitoneally with LPS and D-galactosamine (LPS+GalN) died within 24 h. However, a peritoneal injection, but no intravenous or oral administration, of SCE (500-1,000 mg/kg) at 3 to 48 h before the LPS+GalN-challenge resulted in a significantly improved survival rate. These results suggest that SCE had a protective effect on LPS-induced endotoxin shock via one of possible mechanisms involving the suppression of NO production in the mouse peritoneal cavity.     

Effect of a matrix metalloproteinase inhibitor on host resistance against Listeria monocytogenes infection

Hydroxy acid-based matrix metalloproteinase (MMP) inhibitors have been shown to inhibit tumor infiltration and growth, endotoxin shock, and acute graft-versus-host disease. Blockade of the release of soluble tumor necrosis factor-alpha (TNF-alpha) and CD95 ligand (CD95L; FasL) from cell-associated forms is reportedly involved in the mechanism of the drug effect. We investigated the effect of a MMP inhibitor, KB-R7785, on host resistance against Listeria monocytogenes infection, in which TNF-alpha is essentially required for the defense, in mice. The administration of KB-R7785 exacerbated listeriosis, while the drug prevented lethal shock induced by lipopolysaccharide and D-galactosamine. KB-R7785 inhibited soluble TNF-alpha production in spleen cell cultures stimulated by heat-killed L. monocytogenes and the drug treatment reduced serum TNF-alpha levels in infected mice, whereas the compound was ineffective on the modulation of interferon-gamma and interleukin-10 production. The effect of KB-R7785 was considered to be dependent on TNF-alpha because the drug failed to affect L. monocytogenes infection in anti-TNF-alpha monoclonal antibody-treated mice and TNF-alpha knockout mice. Anti-CD95L monoclonal antibody was also ineffective on the infection. These results suggest that induction of infectious diseases, to which TNF-alpha is critical in host resistance, should be considered in MMP inhibitor-treated hosts.     

Tolerance of mice to lipopolysaccharide is correlated with inhibition of caspase-3-mediated apoptosis in mouse liver cells

Bacterial endotoxin lipopolysaccharide (LPS) often results in multiple organ failure.However,pre-exposure of mice to a sublethal dose of LPS renders the animal tolerant to a lethal dose of LPS.Thisstudy was designed to determine whether pre-exposure of a small dose of LPS was able to suppressapoptosis in mice when challenged with LPS in combination with D-galactosamine,and to investigate theexpression changes of the apoptosis-associated molecules.The results showed that a characteristic apoptoticDNA fragmentation existed in mouse livers of the LPS-naive group,but not in control groups;and the miceof the LPS-naive group were all dead after 2 d.However,in the LPS-tolerance groups,both the lethal rateand apoptotic DNA fragmentation were suppressed after the mice were challenged with LPS/D-galactosamine,and the protection against the lethality and apoptotic reaction could be maintained for up to 7 d.In thisperiod, significantly lower levels of caspase-3 and its mRNA appeared in LPS-tolerant groups compared tothose of the LPS-naive group (P<0.05),and the caspase-3 activities gradually recovered as the observationwas prolonged.Our findings suggest that LPS tolerance could suppress apoptosis in mouse liver cells,andthe expression and activity of caspase-3 could be down-regulated.     

LPS-induced liver injury in D-galactosamine-sensitized mice requires secreted TNF-alpha and the TNF-p55 receptor

Lipopolysaccharide and D-galactosamine induced lethality and apoptotic liver injury is dependent on endogenously produced tumor necrosis factor (TNF)-alpha. The present study was undertaken to determine whether membrane-associated or secreted TNF-alpha signaling through the p55 or p75 receptor was responsible for survival and hepatic injury after lipopolysaccharide administration in D-galactosamine-sensitized mice. Transgenic mice expressing null forms of TNF-alpha, the p55 and p75 receptor, and mice expressing only a cell-associated form of TNF-alpha were challenged with 8 mg D-galactosamine and 100 ng lipopolysaccharide. Mortality and apoptotic liver injury were only seen in wild-type and p75 knockout mice. p75 Knockout mice had significantly higher concentrations of plasma TNF-alpha than any other experimental group (P 相似文献   

Physiological and chemical indicators for early and late stages of sepsis in conscious rats

Endotoxin shock is a major cause of death in patients with septicemia. Endotoxin induces nitric oxide (NO) production and causes tissue damage. In addition, the release of oxygen free radicals has also been observed in endotoxin shock and was found to be responsible for the occurrence of multiple organ failure. The purpose of the present study was to evaluate suitable indicators for early and late stages of endotoxin shock. The experiments were designed to induce endotoxin shock in conscious rats by means of anEscherichia coli lipopolysaccharide (LPS) injection. Arterial pressure (AP) and heart rate (HR) were continuously monitored for 72 h after LPS administration. The maximal decrease in AP and increase in HR and nitrate/nitrite level occurred at 9–12 h following LPS administration. The white blood cell (WBC) count had decreased at 3 h. Hydroxyl radical (methyl guanidine, MG) decreased rapidly after LPS administration. Plasma levels of blood urea nitrogen (BUN), creatinine (Cr), lactic dehydrogenase (LDH), creatine phosphokinase (CPK), and glutamic oxaloacetic transaminase increased before the rise of amylase. Our results suggest that changes in AP, HR, WBC, free radicals, and chemical substances (BUN, Cr) can possibly serve as approximate indicators for the early stage of endotoxin shock. Severe multiple organ damage may be caused by amylase release in the late stage of endotoxin shock.