成年去胸腺大鼠和老年大鼠肝微粒体混合功能氧化酶及血浆性激素水平的变化

成年去胸腺(ATx)大鼠和老年大鼠肝微粒体混合功能氧化酶(MFO,包括细胞色素P450、氨基比林-N-脱甲基酶)的活力比成年对照大鼠的低,且降低幅度雄性明显大于雌性。雄性ATx大鼠和老年大鼠血浆睾酮(T)水平降低,雌二醇(E_2)水平增高,E_2/T比值明显增高;雌性ATx大鼠和老年大鼠血浆E_2和T水平均降低,E_2/T比值无明显变化。给雄性ATx大鼠皮下注射丙酸睾丸素可使其肝微粒体MFO活力恢复。提示胸腺对肝脏MFO的影响可能是通过性激素介导的。     

链脲菌素诱发新生期大鼠糖尿病的量效关系及其胸腺淋巴细胞增殖活性的变化

目的　研究链脲菌素 (STZ)处理新生期大鼠后诱发成年发病糖尿病的量效关系及其胸腺淋巴细胞增殖活性的变化。方法　STZ分别以 2 0、40、6 0及 10 0mg kg ,ip ,给予Wistar新生期大鼠 ,于注射STZ后第 3天、第 7天、第 17天、第 42天观察体重、血糖、血浆胰岛素及胸腺淋巴细胞增殖反应的动态变化。结果　 10 0mg kg剂量组可于第 42天形成慢性糖尿病模型 ,血糖值 (16 8± 4 6 )mmol Lvs (5 8± 1 6 )mmol L ,P <0 0 0 1;血浆胰岛素水平(5 2± 1 2 )mIU Lvs(8 4± 1 6 )mIU L ,P <0 0 1) ,胸腺淋巴细胞增殖呈现升高、受抑制再恢复的变化过程。其他各剂量组 ,特别是 40mg kg虽无明显高血糖形成 ,但可使胸腺淋巴细胞增殖活性增强。结论　STZ(10 0mg kg,ip)处理新生期大鼠诱发糖尿病的最适剂量为 10 0mg kg ,诱发时间为 42d。诱发过程中伴有胸腺增殖活性的变化。     

急性低氧和腺苷对大鼠脾脏T淋巴细胞增殖的影响

目的:观察急性低氧和腺苷对大鼠脾脏T淋巴细胞增殖的影响,以探讨急进高原时机体免疫功能改变的规律和机制.方法:大鼠在5 000 m模拟高原减压低氧3 d后,用3H-TdR掺入法检测脾脏T淋巴细胞增殖功能,增加细胞培养液中腺苷浓度观察对T淋巴细胞增殖的影响.结果:在5.0 mg/L 和2.5 mg/L刀豆素A(concanavalin A,ConA)的刺激下,对照组大鼠脾脏T淋巴细胞的刺激指数分别为64.0±23.7和43.5±21.7;急性低氧组大鼠显著降低至29.4±11.3 和20.2±16.1;10 μmol/L和100 μmol/L腺苷能够显著抑制大鼠脾脏T淋巴细胞的增殖反应,且这种抑制作用具有明显的浓度依赖性.结论:急性低氧可在一定程度上抑制T淋巴细胞功能,这种抑制作用可能与低氧引起的腺苷含量增加有关.     

胸腺因子对老龄雄性大鼠氧自由基及抗氧化剂的作用

目的：探讨胸腺因子对老龄雄性大鼠氧自由基及抗氧化剂的作用。方法：18只21月龄老龄鼠随机分2组。一组隔日皮下注射胸腺因子D(TFD)2mg．kg^-13个月,另一老龄组和9只6月龄幼龄组作对照,注射等体积生理盐水3个月;3个月后,眼眶采血,分离血清检测。结果：老龄雄性大鼠与幼龄鼠比较,MT无变化,NO降低,LPO升高,SOD和CAT降低;TFD处理后,这种老年性改变可得到改善,并接近幼龄对照组水平;这种逆转除NO外都发生在9Am和／或8Pm。结论;胸腺因子可能对延缓衰老有益,其机制可能与胸腺-神经-内分泌-免疫-自由基网络有关。使用TFD以白天为宜。     

番鸭呼肠孤病毒和H9 亚型禽流感病毒共感染对番鸭胸腺免疫抑制作用

【目的】探讨番鸭呼肠孤病毒(muscovy duck reovirus,MDRV)和H9亚型禽流感病毒(H9 avian influenzavirus,AIV)共感染对番鸭胸腺免疫功能的影响。【方法】8日龄番鸭人工感染MDRV或/和H9 AIV,观察番鸭感染后发生率和死亡率、胸腺形态和显微结构变化,淋巴细胞增殖试验检测胸腺细胞增殖功能,RT-PCR检测MDRV或H9 AIV在番鸭胸腺的分布。【结果】H9 AIV感染后番鸭发病率低,无死亡;不影响胸腺的发育,胸腺病理变化不明显,但能显著抑制胸腺淋巴细胞增殖反应。MDRV单独感染番鸭生长迟缓,发病率80%,死亡率50%;胸腺萎缩,出现局限性坏死灶;对番鸭胸腺细胞增殖反应的有抑制作用,差异显著。共感染组番鸭生长迟缓,发病率90%,死亡率70%;胸腺萎缩,淋巴细胞减少,出现局限性坏死灶;对番鸭胸腺细胞增殖反应的有抑制作用,差异极显著。共感染组在病毒检出时间和检出率上均大于单一病毒感染组。【结论】H9AIV感染对胸腺的免疫抑制作用较弱,MDRV感染后对胸腺的免疫抑制作用较强,MDRV与H9AIV共感染在番鸭免疫反应抑制上有协同作用。     

海胆黄多糖SEP对S180的体内抑制作用

研究海胆黄多糖SEP对S180肉瘤的抑制作用及初步机制。MTT法检测SEP对体外培养的S180细胞生长的抑制作用;建立小鼠S180肉瘤模型观察SEP抗肿瘤活性;检测SEP协同ConA/LPS刺激小鼠脾淋巴细胞增殖作用;同时,考察SEP对NK细胞和杀伤性T淋巴细胞(cytotoxic T lym-phocyte,CTL)活性的影响;碳粒廓清检测SEP对小鼠单核巨噬细胞吞噬功能的影响。研究表明,海胆黄多糖SEP高中低剂量(16、8、4 mg/kg)显著抑制小鼠180实体瘤生长,增加小鼠脾指数和胸腺指数,协同ConA/LPS刺激小鼠脾淋巴细胞增殖,提高小鼠NK细胞和CTL活性,增强小鼠单核巨噬细胞的吞噬功能,通过免疫调节提高小鼠免疫功能达到抑制S180作用。     

“深层海水”对小鼠免疫功能的影响

取健康昆明种小鼠72只,随机分为3组,即自来水(tap water,TW)对照组、45 ppm(mg/L)深层海水(deep sea water,DSW)组、90 ppm深层海水组,每组24只,均为雄性,自由喂养8周,观察深层海水对小鼠胸腺指数、脾指数,脾淋巴细胞增殖,巨噬细胞吞噬功能,外周血CD4+、CD8+T细胞百分含量及CD4+/CD8+T细胞比值,血清免疫球蛋白(IgG、IgM、IgA)的影响。结果表明,深层海水可显著提高小鼠胸腺、脾指数,增强巨噬细胞吞噬功能,促进脾淋巴细胞增殖,提高外周血CD4+细胞百分含量及CD4+/CD8+细胞比例,增加血清IgA、IgM含量。因而,深层海水可增强小鼠机体的免疫功能。     

双酚A 对雄性大鼠抗氧化能力影响的初步研究

目的:探讨双酚A(BPA)对成年大鼠抗氧化能力的影响。方法:将健康成年雄性SD大鼠84只随机分为5个双酚A染毒剂量组(200、50、5、0.5、0.0005 mg/kg)和1个对照组,连续灌胃染毒8周,并监测体重变化,染毒结束后测定血浆超氧化物歧化酶(SOD)和谷胱甘肽-过氧化物酶(GSH-Px)含量;此外,提取肝脏组织RNA,用荧光实时定量PCR测定肝脏硫氧还原蛋白过氧化物酶2(prdx2)mRNA的表达水平。结果:随着染毒时间的延长,50 mg/kg及200 mg/kg剂量组的动物体重增长速度逐渐减慢,自4周开始,与对照组相比有显著差异(P<0.05);染毒结束时,其体重分别为对照组的90.52%和91.61%(p<0.05),而其它低剂量组间则无明显差异;大鼠血浆GSH-Px含量总体上呈下降趋势,且5 mg/kg以上剂量组与对照组相比差别均有统计学意义(p<0.01);染毒组血浆SOD水平虽也低于对照组,但无统计显著性;此外,大鼠肝脏组织prdx2 mRNA水平随双酚A剂量增高呈剂量依赖性降低,与对照组相比,其在最低剂量组(0.0005 mg/kg)即有显著差异(p<0.01)。结论:双酚A可造成大鼠抗氧化酶系统失衡,导致氧化损伤效应,prdx2可能是反映其氧化损伤敏感的生物学标志。     

杨梅素对环磷酰胺诱导的免疫抑制小鼠的免疫功能影响CSCD

黄酮类化合物杨梅素(myricetin,MYR)具有抗肿瘤、抗氧化等多种药理作用,但在免疫调节方面的作用尚未完全了解,因此本实验通过建立环磷酰胺(cyclophosphamide,CTX)免疫低下小鼠模型来研究MYR对免疫功能的影响。通过称重小鼠脾脏和胸腺以及计算指数评价MYR对模型小鼠症状的缓解程度,用MTT法、溶血试验、酶联免疫吸附法等免疫学相关实验技术检测T、B淋巴细胞增殖,T细胞亚群分布情况,血清溶血素含量,抗体形成细胞数以及细胞因子白介素-2、白介素-4、白介素-6、干扰素-γ的分泌水平。实验数据表明,MYR能提高小鼠免疫器官脾脏、胸腺指数,促进T淋巴细胞和B淋巴细胞的分泌,提高细胞因子水平和抗体形成细胞数量。结果表明MYR能在免疫反应中起积极作用,调节免疫细胞和细胞因子之间的相互作用恢复机体免疫力的平衡,改善免疫力低下的症状。     

染料木黄酮改善γ射线损伤小鼠抗氧化功能的作用

用137Csγ射线照射雄性昆明小鼠,观察饲料中补充染料木黄酮(Genistein,Gen)对抗氧化功能的保护作用,探讨其抗辐射作用的机制。结果表明,Gen可以提高辐射小鼠脾和胸腺组织总抗氧化能力(T-AOC)、降低血清、肝脏和胸腺组织丙二醛(MDA)水平;显著提高辐射小鼠抗氧化功能。     

Acute lethal graft-versus-host disease stimulates cellular proliferation in the adult rat liver

Abstract. The present investigation was designed to analyse the effects of acute lethal graft-versus-host disease (GVHD) in adult (DA x LEW)F₁ rats on cellular proliferation within the liver. The influence of the host thymus on GVHD-induced proliferation was also assessed. From 1–28 days after initiation of GVHD [³H]thymidine ([³H]-TdR) was injected i.v. and rats were killed one hour later. Percentage labelled cells (LI) of periportal infiltrating cells (PIC), hepatocytes (H), and sinusoidal lining cells (SC) were counted. Mean values for control rats were 0.3 ± 0.1% (H), 0.4 ± 0.1% (SC) and 0.2 ± 0.1% (PIC). GVHD rats demonstrated a significant increase in LI of PIC (days 1–21), SC (days 2–17) and H (days 2–17). Most labelled cells in PIC were large lymphocytes. Peak LI values were 7.0 ± 1.0% PIC (day 17), 6.8 ± 0.9% SC (day 17), and 5.2 ± 0.9% H (day 7), with all cellular compartments returning to near normal LI values by day 28. Stimulation of cellular proliferation occurred in all three liver cell compartments in neonatally thymectomized (TXM) rats. The intensity of GVHD-induced cell proliferation was significantly decreased at day 7 in all compartments and PIC was dramatically decreased at day 21 in TXM-GVHD rats as compared to non-TXM-GVHD rats. It is hypothesized that the general stimulation of hepatocyte cell proliferation in GVHD is related to the secretion of lymphokines by primarily donor and secondarily host T cells in the periportal infiltrate.     

Changes in the composition of phospholipids bound to supramolecular DNA of the thymus and liver in gamma-irradiated rats

The composition of supramolecular DNA (SM DNA)-bound phospholipids (PL) of thymus and liver of intact rats and those 2 min, 2, 6 and 24 h after gamma-irradiation (9,7 Gy) was studied. In norm, supramolecular DNA of the thymus was shown to contain 6.7 micrograms PL/mg DNA, and that of the liver, 6.1 micrograms PL/mg DNA, the main components of PL being cardiolipin (CL) and phosphatidylethanolamine (PEA). Substantial changes were detected in the PL composition of SM DNA of gamma-irradiated rat organs. During the postirradiation period the concentration of PEA and CL in thymus SM DNA changed symbatically and irreversibly decreased to traces; whereas in SM DNA of the liver, their concentrations changed antibatically and decreased only to a definite level thus maintaining the necessary "lipid volume". It was shown that PL were not restored in SM DNA of the radioresistant liver.     

Improvement of the thermostability and catalytic activity of a mesophilic family 11 xylanase by N-terminus replacement

To improve the thermostability and catalytic activity of Aspergillus niger xylanase A (AnxA), its N-terminus was substituted with the corresponding region of Thermomonospora fusca xylanase A (TfxA). The constructed hybrid xylanase, named ATx, was overexpressed in Pichia pastoris and secreted into the medium. After 96-h 0.25% methanol induction, the activity of the ATx in the culture supernatant reached its peak, 633 U/mg, which was 3.6 and 5.4 times as high as those of recombinant AnxA (reAnxA) and recombinant TfxA (reTfxA), respectively. Studies on enzymatic properties showed that the temperature and pH optimum of the ATx were 60 degrees C and 5.0, respectively. The ATx was more thermostable, when it was treated at 70 degrees C, pH 5.0, for 2 min, the residual activity was 72% which was higher than that of reAnxA and similar to that of reTfxA. The ATx was very stable over a broader pH range (3.0-10.0) and much less affected by acid/base conditions. After incubation at pH 3.0-10.0, 25 degrees C for 1 h, all the residual activities of the ATx were over 80%. These results revealed that the thermostability and catalytic activity of the AnxA were enhanced. The N-terminus of TfxA contributed to the observed thermostability of itself and the ATx, and to the high activity of the ATx. Replacement of N-terminus between mesophilic eukaryotic and thermostable prokaryotic enzymes may be a useful method for constructing the new and improved versions of biologically active enzymes.     

Reciprocal T cell responses in the liver and thymus of mice injected with syngeneic tumor cells.

We investigated the T cell responses in various tissues, especially in the liver and thymus, of mice injected with syngeneic tumors. This study was undertaken since recent evidence indicated that the liver is one of the important immune organs for T cell proliferation. When C3H/He mice were intraperitoneally injected with mitomycin-treated syngeneic MH134 tumors (1 x 10(7)/mouse), a transient increase of liver mononuclear cells (MNC) was induced, showing a peak at Day 4 after injection. Histological study of such liver showed a sinusoidal dilatation and an accumulation of MNC in the sinusoids. The most predominant MNC induced were double negative (CD4-8-) alpha beta T cells and gamma delta T cells. These gamma delta T cells varied, showing unique time-kinetics. Despite a continuous increase of whole liver MNC and alpha beta T cells, the proportion of gamma delta T cells in the liver decreased beginning 4 days after injection. In contrast with the response in the liver, a striking decrease in the cell number of thymocytes was induced after tumor injection, showing a basal level at Day 6. This hypocellularity in the thymus appears to be an inverted response of the lymphocytosis in the liver. At this time, a corresponding decrease in the proportion of double positive (CD4+8+) T cells was always seen in the thymus. Analysis of cell proliferative response showed that the increase of liver MNC after tumor injection was accompanied by augmented proliferation, whereas the decrease of thymocytes was accompanied by depressed proliferation. The present results indicate that there exists a unique, reciprocal response of T lymphocytes between the liver and thymus, and that the presence of tumor appears to stimulate T cell response in the liver but alternatively inactivates such response in the thymus.     

Thymus dependency of neonatal tolerance induction in the absence of detectable suppressor cells

Neonatal thymectomy prevents tolerance induction with bovine serum albumin (BSA) in Wistar Furth (WF) rats whose thymus-derived (T) cell deficit is reconstituted with adult nonadherent peripheral blood lymphocytes (PBL). Sham-thymectomized (STx) rats given PBL become tolerant. To establish whether the adult T cells become tolerant in STx rats, their carrier-reactivity was studied in a cooperative immune response following challenge with methylated BSA (mBSA). The results indicate that carrier-reactive cells, derived from PBL, do become tolerant of BSA in the presence, but not in the absence, of the thymus. To determine whether thymic function during tolerance induction is mediated by suppressor T cells, attempts were made to replace the thymus with various populations of thymocytes or lymphoid cells from neonatal or adult normal rats or neonatal BSA-injected rats. No cell population tried could substitute for the thymus during tolerance induction. In addition, it was found that BSA-tolerant rats with intact thymi do not contain either nonspecific suppressor cells whose activity can be boosted with mBSA or specific suppressor activity demonstrable on transfer to normal rats. Timed thymectomy experiments showed that the thymus is required for more than 2, but less than 5 to 7 days after tolerogen injection for significant tolerance induction. These results imply that the thymus itself is necessary for tolerance induction in a peripheral T-cell population and that its effect is not mediated by suppressor cells. It is suggested that peripheral T helper cells may periodically recirculate through the thymus, at least in young rats, and become tolerant of antigen complexed with Ia antigens in the thymic epithelium. Such a mechanism may be of great importance in the development of self-recognition.     

Deregulation of DNA methyltransferases and loss of parental methylation at the insulin-like growth factor II (Igf2)/H19 loci in p53 knockout mice prior to tumor development

To ascertain whether p53 deficiency in vivo leads to the deregulation of DNA methylation machinery prior to tumor development, we investigated the expression profile of DNA methyltransferases in the thymus and the liver of p53(+/+), p53(+/-), and p53(-/-) mice at 7 weeks of age before tumor development. The expression of DNA methyltransferases was examined in the thymus at 7 weeks of age, since the malignant T-cell lymphoma develops most frequently in p53(-/-) mice around 20 weeks of age. Both mRNA and protein levels of Dnmt1 and Dnmt3b were increased in the thymus and the liver of p53-deficient mice. The expression of Dnmt3a was also increased in the liver but not in the thymus of p53-deficient mice. Dnmt3L expression was reduced in the thymus of p53(+/-) and p53(-/-) mice. The total 5-methylcytosine (5-MeC) in the genomic DNA of p53(+/+), p53(+/-), and p53(-/-) mice was quantitated by dot-blot using antibody against 5-MeC. Global methylation was increased in the thymus and the liver of p53-deficient mice. To correlate the deregulated expression of DNA methyltransferases with the disturbance of the epigenetic integrity, we examined the DNA methylation of the imprinting control region (ICR) at the insulin-like growth factor II (Igf2)/H19 loci in the thymus and the liver of p53(+/+), p53(+/-), and p53(-/-) mice. The region containing two CCCTC binding factor (CTCF) binding sites in the 5'-ICR tended to be hypomethylated in the thymus of p53(-/-) mice, but not in the liver. The expression profile of Igf2 and H19 indicated that the thymus-specific changes of Igf2 and H19 expression were coherent to the hypomethylation of the ICR in the thymus. Our results suggest that p53 is required for the maintenance of DNA methylation patterns in vivo.     

Role of the complementarity-determining region 3 (CDR3) of the TCR-beta chains associated with the V alpha 14 semi-invariant TCR alpha-chain in the selection of CD4+ NK T Cells

The NK1.1(+)TCRalphabeta(int) CD4(+), or double negative T cells (NK T cells) consist of a mixture of CD1d-restricted and CD1d-unrestricted cells. The relationships between CD4(+)NK1.1(+) T cells and conventional T cells are not understood. To compare their respective TCR repertoires, NK1.1(+)TCRalphabeta(int), CD4(+) T cells have been sorted out of the thymus, liver, spleen, and bone marrow of C57BL/6 mice. Molecular analysis showed that thymus and liver used predominantly the Valpha14-Jalpha281 and Vbeta 2, 7, and 8 segments. These cells are CD1d restricted and obey the original definition of NK T cells. The complementarity-determining region 3 (CDR3) sequences of the TCR Vbeta8.2-Jbeta2.5 chain of liver and thymus CD4(+) NK T cells were determined and compared with those of the same rearrangements of conventional CD4(+) T cells. No amino acid sequence or usage characteristic of NK T cells could be evidenced: the Vbeta8.2-Jbeta2.5 diversity regions being primarily the same in NK T and in T cells. No clonal expansion of the beta-chains was observed in thymus and liver CD1d-restricted CD4(+)NK T cells, suggesting the absence of acute or chronic Ag-driven stimulation. Molecular analysis of the TCR used by Valpha14-Jalpha281 transgenic mice on a Calpha(-/-) background showed that the alpha-chain can associate with beta-chains using any Vbeta segment, except in NK T cells in which it paired predominately with Vbeta 2, 7, and 8(+) beta-chains. The structure of the TCR of NK T cells thus reflects the affinity for the CD1d molecule rather than a structural constraint leading to the association of the invariant alpha-chain with a distinctive subset of Vbeta segment.     

定量蛋白质组学研究揭示知母可缓解2型糖尿病模型大鼠肝脏代谢异常

2型糖尿病(type 2 diabetes mellitus, T2DM)是一种在全球范围内广泛存在的代谢性疾病,不及时治疗可能会引发众多危及生命的并发症。肝脏代谢在糖尿病发生发展的过程中扮演着至关重要的角色。目前已有报道中药知母用于缓解胰岛素抵抗及糖尿病,但其能否缓解糖尿病中肝脏代谢的异常仍有待深入研究。因此,提取了高脂饮食和化学药物链脲佐菌素(streptozotocin, STZ)诱导的2型糖尿病大鼠模型、知母提取物处理的2型糖尿病大鼠模型、高脂饮食大鼠模型以及正常饮食大鼠对照组的肝脏蛋白,通过基于质谱的定量蛋白质组学串联质量标签(tandem mass tag, TMT)标记技术获得定量蛋白质组数据。利用生物信息学软件对各组数据进行层次聚类分析及主成分分析,并以P<0.05,差异倍数(fold change)>1.5作为阈值标准进行火山图分析,发现知母提取物治疗组相较未治疗组与正常对照组更接近,表明肝脏组织定量蛋白质组数据能够反映知母提取物对2型糖尿病大鼠模型的治疗效果。筛选获得了表达水平与知母提取物治疗密切相关的关键蛋白簇。利用在线网站分析蛋白簇的GO功能与KEG...     

Emergence of T cell progenitors without B cell or myeloid differentiation potential at the earliest stage of hematopoiesis in the murine fetal liver

It has been unclear whether the progenitors colonizing the thymus are multipotent or T cell lineage restricted. We investigated the developmental potential of hematopoietic progenitors in various populations of liver and blood cells from day 12 fetuses using the recently established in vitro experimental system effective in determining the capability of individual progenitors to generate T, B, and myeloid cells. Multipotent progenitors (p-Multi) were exclusively found in the Sca-1 high-positive (Sca-1high) subpopulation of lineage marker (Lin)-c-kit+CD45+ fetal liver cells. Restriction of developmental capacity begins at the Sca-1high stage, and a large majority of progenitors in the Sca-1low or Sca-1- population are restricted to generate T, B, or myeloid cells. Such a lineage commitment or restriction taking place in the fetal liver is independent of the thymus, because no difference in the proportion of different types of progenitors were seen between nu/nu and nu/+ fetuses. T cell lineage-restricted progenitors (p-T) were abundant in the blood of day 12 fetuses, whereas p-Multi were undetectable. It was further shown that the p-Multi generated a large number of B and myeloid cells in the thymic lobe. These results strongly suggest that it is p-T but not p-Multi that migrate into the thymus.