双歧杆菌总DNA对小鼠IL—2,NK活性影响的研究

目的 从双歧杆菌、大肠杆菌提取ＤＮＡ,用ＤＮＡ免疫小鼠,观察免疫功能的变化,探讨双歧杆菌ＤＮＡ对小鼠免疫功能的影响,并作对比研究。方法 肌肉注射提取的双歧杆菌ＤＮＡ、大肠杆菌ＤＮＡ,颈椎处死后,检测脾细胞的免疫功能,同时提取ＩＥＬ细胞与ＤＮＡ共孵育,检测它对ＩＥＬ细胞的激活情况及细胞因子产生情况,以自然杀伤细胞（ＮＫ）活性,白细胞介素２（ＩＬ－２）产生能力为指标,测定小鼠上述各项指标变化。结果 双歧杆菌ＤＮＡ、大肠杆菌ＤＮＡ肌肉注射后,小鼠以上两项指标与相应对照组相比较均明显提高（Ｐ〈０．０５）。双歧杆菌ＤＮＡ提高小鼠ＮＫ活性与ＩＬ－２水平程度大于大肠杆菌ＤＮＡ的作用（Ｐ〈０．０１）。结论 双歧杆菌ＤＮＡ可快速激活ＮＫ活性,提高体内ＩＬ－２水平。其效能优于大肠杆菌ＤＮＡ。     

富硒双歧杆菌缓解5-FU导致的化疗性肠粘膜炎的药效学研究

通过腹腔注射5-FU建立小鼠肠黏膜炎模型,探讨富硒长双歧杆菌(Selenium-enriched Bifidobacterium longum,Se-B.longum)能否改善5-FU所致的小鼠肠黏膜炎。将健康BALB/c小鼠随机分为对照组、5-FU组和Se-B.longum/5-FU组,分别灌胃生理盐水、生理盐水和Se-B.longum(Se0.3 mg/kg BW,1×106bacteria/只)6 d,然后5-FU组和Se-B.longum/5-FU组小鼠均腹腔注射5-FU(250 mg/kg),观察小鼠腹泻及死亡情况,5 d后处死小鼠,计算体重变化、脏器指数及考察肠道组织变化;将健康BALB/c小鼠随机分为对照组、5-FU组和Se-B.longum/5-FU组,分别灌胃生理盐水、生理盐水和Se-B.longum(Se 0.3 mg/kg BW,1×106bacteria/只)6 d,然后5-FU组和Se-B.longum/5-FU组小鼠均腹腔注射5-FU(300 mg/kg),观察小鼠死亡情况,绘制生存曲线。Se-B.longum能缓解5-FU导致的正常小鼠的肠粘膜炎、降低小鼠死亡率。     

双歧杆菌增强小鼠机体的免疫功能

【目的】本研究针对实验室自行从内蒙传统发酵乳制品中分离得到的两株双歧杆菌Bifidobacterium adolescentis BB-2和B.longum BB-3,对其调节机体免疫的功能进行了评价。【方法】采用健康SPF级BALB/c小鼠,每组10只,空白组灌胃无菌脱脂乳,阳性对照组灌胃含有商业菌株BB-12的无菌脱脂乳,处理组同样以无菌脱脂乳为溶液,灌胃含有不同剂量的Bifidobacterium adolescenti BB-2或B.longum BB-3,测定细胞免疫(迟发型变态反应DTH、脾淋巴细胞增殖MTT显色反应、自然杀伤细胞活性),体液免疫(绵羊红细胞免疫后的血清溶血素活性),以及非特异性免疫(巨噬细胞吞噬活性)指标。【结果】表明BB-2和BB-3两株双歧杆菌均能够增强DTH反应。双歧杆菌组小鼠的巨噬细胞的吞噬活性也有提高,同时自然杀伤细胞活性及血清溶血素水平也高于对照组,菌株处理组的脾淋巴细胞增殖率也有提高。剂量效应不显著,其中低剂量浓度(102-6cfu/m L)即可发挥作用。【结论】证明双歧杆菌BB-2和BB-3能够促进小鼠先天性免疫力和获得性免疫力的提高。本研究的开展对开发我国具有自主产权的功能菌株具有重要意义。     

长双歧杆菌完整肽聚糖对小鼠免疫功能的影响

目的比较长双歧杆菌及其完整肽聚糖的免疫调节作用。方法通过研究长双歧杆菌完整肽聚糖对植瘤小鼠淋巴细胞的转化、抑瘤率、生命延长期以及对细胞Bcl-2和Bax表达的影响来探讨它们对小鼠细胞免疫的调节作用。结果与对照组相比,完整肽聚糖使淋巴细胞转化增加、抑瘤率提高、延长生命期增加、Bcl-2阳性表达率减小而Bax基因表达增加。结论长双歧杆菌与其完整肽聚糖均有抑制S180肿瘤的作用,但完整肽聚糖的效果优于长双歧杆菌。     

分叉双歧杆菌对小鼠腹水瘤的抑制作用

本文观察了分叉双歧杆菌对小鼠腹腔移植的淋巴细胞腹水瘤(SRS)的抑制作用。结果发现,分叉双歧杆菌在SRS瘤细胞移植前或移植后应用,均能明显抑制瘤细胞的生长,特别在移植后应用,抗瘤效果更显著。主要表现为荷瘤小鼠存活时间延长、存活率提高。将该菌预先进行处理或不处理后加入体外培养的SRS瘤细胞中,发现该菌对离体的瘤细胞生长也有直接抑制作用。     

双歧因子对双歧杆菌增殖的影响

应用含有不同浓度的双歧因子(微维乐)的培养基对双歧杆菌进行了定性、定量观察。其结果表明,微维乐对双歧杆菌有明显的促进作用;在双歧杆菌制剂的生产过程中,添加一定量的微维乐,不仅可以提高双歧杆菌收率,而且还可以缩短菌种发酵时间。最佳添加量为1.5%,最佳发酵时间为1.5 h。     

青春型双歧杆菌生态制品对小鼠肝癌抑制作用的初步研究

本文观察了青春型双歧杆菌(Bif.a)对小鼠肝癌移植瘤的抑制作用。结果发现,青春型双歧杆菌在瘤细胞移植前或移植后应用均显示了抑制肿瘤生长的作用。将青春型双歧杆菌注入肤腔可激活肤腔巨噬细胞,提高其吞噬功能和非特异性酯酶活性,而加入体外培养的小鼠肝癌细胞未显示有杀伤瘤细胞作用。认为青春型双歧杆菌的抑瘤作用可能是该菌刺激了宿主的免疫活性细胞杀伤了瘤细胞,而非直接杀伤作用。     

双歧杆菌发酵果蔬汁对小鼠抗疲劳作用的实验研究

目的检测发酵果蔬汁对小鼠的抗疲劳作用。方法将3种果蔬汁按一定比例加入双歧杆菌、保加利亚乳杆菌和嗜热链球菌,经发酵,分别以高中低3个剂量喂食小鼠30d后,进行小鼠负重游泳实验,检测肝糖原、乳酸和尿素氮等各项抗疲劳指标。结果3种果蔬汁均能显著延长小鼠负重游泳时间,提高小鼠肝糖原的储备量;降低小鼠游泳后血乳酸和尿素氮均值,增加血红蛋白含量及乳酸脱氢酶活性,减少血尿酸含量。且抗疲劳强度程度与型量声低有一定相差。结论3种发酵果蔬汁具有抗疲劳作用。     

双歧杆菌总DNA对小鼠IL-2、NK活性影响的研究

目的　从双歧杆菌、大肠杆菌提取 DNA,用 DNA免疫小鼠 ,观察免疫功能的变化 ,探讨双歧杆菌 DNA对小鼠免疫功能的影响 ,并作对比研究。方法　肌肉注射提取的双歧杆菌 DNA、大肠杆菌 DNA,颈椎处死后 ,检测脾细胞的免疫功能 ,同时提取 IEL细胞与 DNA共孵育 ,检测它对 IEL细胞的激活情况及细胞因子产生情况 ,以自然杀伤细胞 (NK)活性 ,白细胞介素 2 (IL - 2 )产生能力为指标 ,测定小鼠上述各项指标变化。结果　双歧杆菌 DNA、大肠杆菌 DNA肌肉注射后 ,小鼠以上两项指标与相应对照组相比较均明显提高 (P<0 .0 5 )。双歧杆菌 DNA提高小鼠 NK活性与 IL - 2水平程度大于大肠杆菌 DNA的作用(P<0 .0 1)。结论　双歧杆菌 DNA可快速激活 NK活性 ,提高体内 IL - 2水平。其效能优于大肠杆菌DNA。     

双歧杆菌对小鼠肝癌腹水瘤细胞Ca~(2 )-ATPase及糖原磷酸化酶a的影响

采用青春型双歧杆菌菌液与小鼠肝癌腹水瘤细胞 HCa/16 A 3- F相互作用 ,测定其对细胞糖原磷酸化酶 a和微粒体 Ca2 - ATPase活性的影响 ,发现两种酶的活性均明显低于对照组 ,这与细胞内其他一些钙稳态指标的变化相一致。提示双歧杆菌菌液对此腹水瘤钙稳态具有一定的影响 ,可为双歧杆菌的抗肿瘤作用提供一定的依据     

Oral administration of Bifidobacterium longum prevents gut-derived Pseudomonas aeruginosa sepsis in mice

Aims: The aim of the study was to evaluate the efficacy of probiotics on gut‐derived sepsis caused by Pseudomonas aeruginosa in immunocompromised mice. Methods and Results: After oral inoculation of P. aeruginosa, mice were treated with cyclophosphamide to induce leucopenia and translocation of the intestinal P. aeruginosa into blood, thereby producing gut‐derived sepsis. In this model, administration of 1 × 10⁹ CFU of Bifidobacterium longum strain BB536 for 10 days significantly (P < 0·01) increased the survival rate compared with groups of mice administered either with Bifidobacterium breve strain ATCC 15700 or excipients contained in the probiotic bacterial powder. Administration of B. longum significantly decreased viable counts of P. aeruginosa in the liver and blood compared with other groups. Culture of intestinal contents revealed a significantly lower viable count of P. aeruginosa in the jejunum of B. longum‐treated mice compared with other groups of mice. Furthermore, in vitro data demonstrated that B. longum possessed apparently higher adherent activity to Caco‐2 cell monolayers and significantly suppressed the adherence of P. aeruginosa to the monolayers of cells compared with other groups. Conclusion: Oral administration of B. longum protects mice against gut‐derived sepsis caused by P. aeruginosa, and the effect may be due to interference of P. aeruginosa adherence to intestinal epithelial cells. Significance and Impact of this Study: This study demonstrated that oral administration of B. longum BB536 is effective to protect against opportunistic infection with drug‐resistant bacteria such as P. aeruginosa. The results suggest that probiotics may play an important role even in the immunocompromised patients.     

Interleukin-10 gene therapy reverses thioacetamide-induced liver fibrosis in mice

Hepatic fibrosis represents a process of healing and scarring in response to chronic liver injury. Interleukin-10 (IL-10) is a cytokine that downregulates the proinflammatory response and has a modulatory effect on hepatic fibrogenesis. The aim of this study was to investigate whether IL-10 gene therapy possesses anti-hepatic fibrogenesis in mice. Liver fibrosis was induced by long-term thioacetamide administration in mice. Human IL-10 expression plasmid was delivered via electroporation after liver fibrosis established. IL-10 gene therapy reversed hepatic fibrosis and prevented cell apoptosis in a thioacetamide-treated liver. RT-PCR revealed IL-10 gene therapy to reduce liver transforming growth factor-beta1, tumor necrosis factor-alpha, collagen alpha1, cell adhesion molecule, and tissue inhibitors of metalloproteinase mRNA upregulation. Following gene transfer, the activation of alpha-smooth muscle actin and cyclooxygenase-2 was significantly attenuated. In brief, IL-10 gene therapy might be an effective therapeutic reagent for liver fibrosis with potential future clinical applications.     

Interleukin-2 inhibits proliferation of HPV-associated tumor cells and halts tumor growth in vivo

Previous studies have shown inhibition of cervical cancer cell growth by treatment with high concentrations of IL-2. In the present study, we evaluated the in vitro and in vivo effects of recombinant human IL-2 on HPV-associated tumor cells (3T3-16). Treatment of 3T3-16 cells with rhIL-2 for 72 h inhibited cell growth in a dose-dependent manner and this effect was evidenced at nanomolar concentrations. These tumor cells expressed mRNA for beta and gamma subunits of the IL-2 receptor, which are required for signal transduction. In experiments to explore the effect of IL-2 on the growth of the HPV-associated tumor, mice received rhIL-2 through different routes: (i) intraperitoneal; (ii) subcutaneous, at the tumor inoculation site; or (iii) subcutaneous, distant from the tumor inoculation site. An effective antitumor response was observed only in those animals that received IL-2 at the tumor site (P<0.01). These results indicate the potential adequacy of therapeutic strategies based on local administration of rhIL-2 for cervical carcinoma, not only based on the ability of this cytokine to stimulate cellular-mediated immunity but also because of its direct effects on tumor cells.     

Consecutive oral administration of Bifidobacterium longum MM‐2 improves the defense system against influenza virus infection by enhancing natural killer cell activity in a murine model

Bifidobacterium, one of the major components of intestinal microflora, shows anti‐influenza virus (IFV) potential as a probiotic, partly through enhancement of innate immunity by modulation of the intestinal immune system. Bifidobacterium longum MM‐2 (MM‐2), a very safe bacterium in humans, was isolated from healthy humans and its protective effect against IFV infection in a murine model shown. In mice that were intranasally inoculated with IFV, oral administration of MM‐2 for 17 consecutive days improved clinical symptoms, reduced mortality, suppressed inflammation in the lower respiratory tract, and decreased virus titers, cell death, and pro‐inflammatory cytokines such as IL‐6 and TNF‐α in bronchoalveolar lavage fluid. The anti‐IFV mechanism of MM‐2 involves innate immunity through significant increases in NK cell activities in the lungs and spleen and a significant increase in pulmonary gene expression of NK cell activators such as IFN‐γ, IL‐2, IL‐12 and IL‐18. Even in non‐infected mice, MM‐2 administration also induced significant enhancement of both IFN‐γ production by Peyer's patch cells (PPs) and splenetic NK cell activity. Oral administration of MM‐2 for 17 days activates systemic immunoreactivity in PPs, which contributes to innate immunity, including NK cell activation, resulting in an anti‐IFV effect. MM‐2 as a probiotic may function as a prophylactic agent in the management of an IFV epidemic.     

大肠杆菌-长双歧杆菌穿梭载体的构建及PTEN在长双歧杆菌中的表达

长双歧杆菌可特异地定植于实体瘤低氧区,可用做肿瘤靶向性基因治疗的载体,而构建大肠杆菌-长双歧杆菌穿梭质粒则被证明是外源基因在长双歧杆菌中稳定表达的有效途径。为了构建能在长双歧杆菌中稳定表达外源基因的穿梭质粒并检测携带抑癌基因的工程菌对小鼠实体瘤的抑制效果,利用软件设计并合成了48条部分序列相互重叠的引物,通过PCR合成了长双歧杆菌质粒pMB1序列及长双歧杆菌HU启动子区序列,插入克隆载体pMD18-T,构建穿梭载体pMB-HU,该载体可在大肠杆菌DH5α及长双歧杆菌L17中稳定复制。PTEN基因编码具有蛋白质和酯类双重特异性磷酸酶活性的抑癌因子。将PTEN基因cDNA序列插入载体pMB-HU中HU启动子下游,构建重组质粒pMB-HU-PTEN,电击转化长双歧杆菌后,Western blot检测表明,表达产物中存在55kDa的PTEN蛋白特异条带。抑癌试验表明:与对照组相比,携带PTEN基因的长双歧杆菌可显著抑制小鼠实体瘤的生长。上述结果为以长双歧杆菌为载体的实体瘤靶向性基因治疗研究奠定了基础。     

Interleukin-17 programs liver progenitor cell transformation into cancer stem cells through miR-122 downregulation with increased risk of primary liver cancer initiation

Chronic inflammation is a key component in the development of virtually all types of primary liver cancers. However, how chronic inflammation potentiates or even may initiate liver parenchymal cell transformation remains unclear. Cancer stem cells (CSCs) represent an exciting target for novel anticancer therapeutic strategies in several types of cancers and were also described in primary liver cancers as tumor initiating cells. Recently, we reported a key role of Interleukin (IL)-17 in Liver Progenitor Cell (LPC) accumulation in preneoplastic cirrhotic livers. In this study, we evidenced in vitro, that long-term stimulation of LPCs with IL-17 led to their transformation into CSCs. Indeed, they acquired CSC-marker expression, and self-renewal properties, showed by their increased capacity to form spheroids. The miRNome analysis revealed that long-term IL-17 treatment of LPCs led to a 90% decrease in miR-122 expression. In a model using immunodeficient mice, ectopic engraftment of LPCs in an IL-17-enriched environment led to tumor occurrence with an aggressive phenotype. Contrastingly, in a murine model of hepatocellular carcinoma induced by a unique injection of diethyl-nitrosamine associated with chronic administration of carbon tetrachloride, IL-17-deficiency or anti-IL-17 therapy protected mice from liver tumor growth. In conclusion, we showed that a chronic exposure of LPCs to IL-17 cytokine promotes their transformation into CSCs. In addition, we demonstrated that IL-17-neutralizing strategies limit CSC occurrence and liver tumor progression through miR-122 restored-expression.     

黄瓜香联合顺铂治疗小鼠H22肝癌的研究

目的 观察黄瓜香联合顺铂对小鼠H22肝癌移植瘤生长的抑制作用.方法 将40只接种H22肝癌细胞的昆明小鼠随机分为4组,其腹腔分别注射生理盐水(对照组);黄瓜香组;顺铂组;黄瓜香+顺铂组(联合治疗组),观察小鼠的毒副反应及生存质量.实验19 d后,处死全部小鼠,剥离皮下肿瘤,称小鼠肿瘤重量,计算抑瘤率.结果 黄瓜香组的H22肝癌平均瘤重为(1.26 ±0.19)g,明显低于对照组的(1.89 ±0.56)g(P ＜0.01).联合治疗组的平均瘤重为(0.57 ±0.42)g,均明显低于黄瓜香组(P＜0.01)和顺铂组(P＜0.01);其抑瘤率达69.8％,明显高于黄瓜香组(x2=16.9875,P＜0.01)和顺铂组(x2=5.0602,P＜0.05).联合治疗组小鼠的毒副反应明显低于顺铂组,生存质量好于顺铂组;黄瓜香组与联合治疗组都能调节肠道菌群,扶植肠道中有益菌(乳酸杆菌和双歧杆菌)生长,抑制大肠埃希菌生长,与对照组比较差异具有统计学意义(P＜0.01).结论 黄瓜香与顺铂合用对小鼠H22肝癌移植瘤的生长具有协同抑制作用,能降低顺铂毒副反应,提高小鼠的生存质量.     

Oral Administration of an Immunostimulatory DNA Sequence from Bifidobacterium longum Improves Th1/Th2 Balance in a Murine Model

We have reported the antiallergic activities of the immunostimulatory oligodeoxynucleotide (ODN) BL07S, identified from genomic DNA of Bifidobacterium longum BB536 from in vitro and in vivo studies. The present study evaluated the efficiency of ODN BL07S in preventing allergic responses by oral administration. Oral administration of BL07S suppressed serum ovalbumin (OVA)-specific immunoglobulin (Ig) E levels and improved the OVA-specific IgG2a/IgG1 ratio. ODN BL07S increased Th1 cytokine and decreased Th2 cytokine production in splenocytes. These results suggest that immunostimulatory ODNs are potentially associated with the antiallergic effects of probiotics.     

Comparison between crude Interleukin-2 and recombinant Interleukin-2 in maintaining killing activity of cultured lymphocytes

Peripheral blood lymphocytes, regional lymph node lymphocytes or malignant effusion lymphocytes from cancer patients were incubated with crude IL-2 (cIL-2) for 13 days. These effectors, which frequently expressed IL-2 receptor (IL-2R), proliferated well and possessed augmented killing activity against fresh autologous tumor cells and K562. However, when recombinant IL-2 (rIL-2) was added for the last 4 days of culture instead of cIL-2, IL-2R expression and killing activity against fresh autologous tumor cells decreased significantly (P<0.05). Phenotypic analysis indicated that cIL-2 significantly promoted the expansion of the cytotoxic population (CD8⁺ .11b^–)(P<0.05). The decreases in killing activity and IL-2R expression were restored by 0.004% PHA plus rIL-2, but not in the presence of rIFN-, rIL-1, rIL-l, rIL-4 or rIL-6. PHA-free cIL-2 maintained killing activity, but not IL-2R expression.We conclude that some factors in cIL-2 and a low dose of PHA-P are necessary for the maintenance of killing activity and IL-2R expression of cultured lymphocytes in the late phase of culture.