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1.
Hypoxia is a condition of low oxygen level which poses a common feature of most cancers. In the current study, we investigated effect of water containing oxygen nanobubble (ONB) on tumor growth in breast cancer 4T1-bearing mice during 14-day treatment period. Tumor-bearing mice were randomly divided into three groups (six mice per group), including the ONB group drinking water containing ONB, the air nanobubble (ANB) group drinking water containing ANB, and control group drinking normal water. Tumor weight and size were measured in 2-day interval during 14-day treatment. mRNA expression of p53, vascular endothelial growth factor (VEGF), hypoxia-inducible factor (HIF), and cyclin D/Cdk2 genes were measured in the treated and control mice. After 8, 12, and 14 days of treatment, tumor size in ONB group was significantly decreased by 40.5%, 32.8%, and 28%, respectively, when compared with the control group. In addition, ANB group showed a significant reduction in tumor burden as well. The messenger RNA (mRNA) level of p53 in tumor cells of ONB and ANB group was found to be 36-fold (P = 0.0001) and 33-fold (P = 0.0001) higher than that in the control group, respectively. There was a ninefold increase in mRNA expression of VEGF gene in tumor cells of ANB mice than that in control mice; however, there was no significant changes in ONB group. Expression of HIF gene was significantly lower in tumor cells of ONB and ANB group than in the control group. It is concluded that drinking ONB water has potential to inhibit tumor growth, however more preclinical and proof-of-concept studies are needed to confirm its safety and therapeutic effect.  相似文献   

2.
Based on theoretical estimates and various correlation studies, it has been suggested that ingestion of radon in drinking water represents an increased risk for cancer. Such a risk has never been conclusively shown in epidemiological or experimental animal studies, however, and it has been questioned whether the radon level in the drinking water is of any significance in terms of overall radon exposure. Using primary DNA damage as a biological marker for an ongoing exposure to ionising radiation, the present study was undertaken to investigate whether people with different types of residential radon exposures differed with regard to their levels of DNA damage in circulating lymphocytes. DNA damage was measured in coded blood samples from 125 residents living in 45 households with different levels of radon-222 in the drinking water (10-2410 Bq/l) and indoor air (35-1025 Bq/m3) using alkaline single cell gel electrophoresis (the 'Comet' assay). Increased levels of radon in indoor air (>200 Bq/m3) were found to be associated with an increased level of DNA damage in peripheral lymphocytes (P相似文献   

3.
Selenium added to the diet significantly lowers the incidence of spontaneous mammary adenocarcinoma in female inbred C3H/St mice infected with the Bittner Milk Factor. Lead, 5 ppm, added to the drinking water in the form of the acetate, diminishes the uptake of selenium and reduces its anticarcinogenic effects, causing mammary tumors to appear with the same high incidence as in Se-unsupplemented controls. At higher lead concentrations in the drinking water (25 ppm), the overall tumor incidence is lowered, but tumor growth is significantly accelerated and the survival of tumor-bearing mice is shortened. Under the conditions of administration chosen, lead acts as a selenium antagonist and lowers the concentrations of selenium in liver, kidney, and spleen. The deposition of selenium, copper, and arsenic in bone is increased as compared to lead-unexposed controls.  相似文献   

4.
An immunosuppressed mouse model was used to determine the effects of amprolium and sulfadiazine on experimental Neospora caninum infections. Both drugs were given in the drinking water. Neither drug was effective in treating infections when given 7 days after inoculation of tachyzoites, when clinical signs of disease had developed. Amprolium did not prevent deaths or development of clinical signs when given in the drinking water at 1 mg/ml or 5 mg/ml 3 days after inoculation of tachyzoites. Sulfadiazine in drinking water was not effective when given at 0.5 mg/ml but was effective in preventing deaths and clinical disease when given at 1 mg/ml 3 days after inoculation with tachyzoites. Most mice (6 of 10) treated for 3 days with 1 mg/ml sulfadiazine in drinking water developed encephalitis after drug treatment was stopped. Treatment for 14 days with 1 mg/ml sulfadiazine in drinking water was needed to protect 90% of inoculated mice.  相似文献   

5.
The presence of radon in drinking water causes radiation-related health hazards both through inhalation and ingestion. In the present study, 28 drinking water samples from natural flowing springs, freshwater ponds, and deep hand pumps were analyzed in the fault zone of Reasi region of Jammu &; Kashmir. Radon measurement was performed using the RAD7 electronic device for radon content determination. Average mean values of these samples vary from 2.80 ± 0.78 to 74.37 ± 2.76 Bq l?1. Nineteen drinking water samples analyzed have radon levels in excess of USEPA recommended maximum contamination level of 11.1 Bq l?1. The annual effective dose from radon in water due to its ingestion and inhalation per individual has also been calculated. Uranium concentration in these water samples was also analyzed for a possible correlation between different types of rocks and values of radon in water. Results obtained have been compared with the results of earlier investigators for mean radon concentration and mean annual effective dose for radon in water from different regions of northern India and Pakistan. It has been found that radon levels in a significant number of water samples collected from the region of fault line are higher than USEPA recommendations. A positive correlation is observed between the depth of the water source and the values of radon levels in water samples collected from these sources. Measurements of radon concentration in these water samples were also performed with a Smart Radon Monitor designed by Bhabha Atomic Research Centre, Trombay, Mumbai, India, for a comparative analysis.  相似文献   

6.
Hemicalcium ascorbate (Ca-Asc, 51 mM, 1% wt/vol), added to the drinking water, had the following effects in DBA/2 mice inoculated with 105 S91 (Cloudman) melanoma cells: 1) it delayed the appearance of visible tumors by 2–4 weeks; 2) it increased the survival rate at three months after tumor challenge by 12–50%; 3) it had no significant effect on the rate of tumor growth once the size of the tumors had reached 10 mm3; 4) the inhibition was maximal when the treatment with Ca-Asc was started at leasr one week prior to the inoculation of cells 5) when free ascorbic acid was used instead of Ca-Asc, the animals consumed 50% less water, they became dehydrated and the treatment was less effective; 6) Ca++ (51 mM) alone had no significant inhibitory effect. --Since Ca Asc (1 mM) was not toxic to S91 melanoma cells in vitro, we suggest that prophylactic treatment of the animals with Ca-Asc inhibited tumor development by increasing the resistance of the host.  相似文献   

7.
It has been demonstrated in various animal models that the oral administration of green tea (GT) extracts in drinking water can inhibit tumor growth, but the effects of brewed GT on factors promoting tumor growth, including oxidant damage of DNA and protein, angiogenesis and DNA methylation, have not been tested in an animal model. To explore these potential mechanisms, brewed GT was administered instead of drinking water to male severe combined immunodeficiency (SCID) mice with androgen-dependent human LAPC4 prostate cancer cell subcutaneous xenografts. Tumor volume was decreased significantly in mice consuming GT, and tumor size was significantly correlated with GT polyphenol (GTP) content in tumor tissue. There was a significant reduction in hypoxia-inducible factor 1-alpha and vascular endothelial growth factor protein expression. GT consumption significantly reduced oxidative DNA and protein damage in tumor tissue as determined by 8-hydroxydeoxyguanosine/deoxyguanosine ratio and protein carbonyl assay, respectively. Methylation is known to inhibit antioxidative enzymes such as glutathione S-transferase pi to permit reactive oxygen species promotion of tumor growth. GT inhibited tumor 5-cytosine DNA methyltransferase 1 mRNA and protein expression significantly, which may contribute to the inhibition of tumor growth by reactivation of antioxidative enzymes. This study advances our understanding of tumor growth inhibition by brewed GT in an animal model by demonstrating tissue localization of GTPs in correlation with inhibition of tumor growth. Our results suggest that the inhibition of tumor growth is due to GTP-mediated inhibition of oxidative stress and angiogenesis in the LAPC4 xenograft prostate tumor in SCID mice.  相似文献   

8.
The effect of caffeine given as pre- and post-treatment in mice exposed to whole-body gamma-irradiation (1.5 Gy 60Co gamma-rays) was studied. The pre-treatment was either acute or chronic. The acute dose (5 mg/kg and 15 mg/kg body weight) was in the form of an injection given intraperitoneally, 30 min before irradiation. The chronic administration was in the form of caffeine solution (4.208 x 10(-3) M and 7.72 x 10(-4) M) contained in the drinking water that mice had had ad libitum access to instead of plain drinking water for 5 weeks prior to radiation exposure. The acute pre-treatment with caffeine reduced the radiation-induced frequency of chromosomal aberrations discernibly, whereas the chronic pre-treatment afforded a much more significant degree of radioprotection. The caffeine post-treatment (5 mg/kg and 15 mg body weight) was given in the form of an intraperitoneal injection to the mice immediately following whole-body gamma-irradiation. It is noted that both post-treatment concentrations of caffeine also significantly reduced the frequency of chromosomal aberrations induced by gamma-rays. These data are briefly discussed in terms of possible mechanistic considerations.  相似文献   

9.
Cancer metastases arise in part from disseminated tumor cells originating from the primary tumor and from residual disease persisting after therapy. The identification of biomarkers on micro-metastases, disseminated tumors, and residual disease may yield novel tools for early detection and treatment of these disease states prior to their development into metastases and recurrent tumors. Here we describe the molecular profiling of disseminated tumor cells in lungs, lung metastases, and residual tumor cells in the MMTV-PyMT breast cancer model. MMTV-PyMT mice were bred with actin-GFP mice, and focal hyperplastic lesions from pubertal MMTV-PyMT;actin-GFP mice were orthotopically transplanted into FVB/n mice to track single tumor foci. Tumor-bearing mice were treated with TAC chemotherapy (docetaxel, doxorubicin, cyclophosphamide), and residual and relapsed tumor cells were sorted and profiled by mRNA microarray analysis. Data analysis revealed enrichment of the Jak/Stat pathway, Notch pathway, and epigenetic regulators in residual tumors. Stat1 was significantly up-regulated in a DNA-damage-resistant population of residual tumor cells, and a pre-existing Stat1 sub-population was identified in untreated tumors. Tumor cells from adenomas, carcinomas, lung disseminated tumor cells, and lung metastases were also sorted from MMTV-PyMT transplant mice and profiled by mRNA microarray. Whereas disseminated tumors cells appeared similar to carcinoma cells at the mRNA level, lung metastases were genotypically very different from disseminated cells and primary tumors. Lung metastases were enriched for a number of chromatin-modifying genes and stem cell-associated genes. Histone analysis of H3K4 and H3K9 suggested that lung metastases had been reprogrammed during malignant progression. These data identify novel biomarkers of residual tumor cells and disseminated tumor cells and implicate pathways that may mediate metastasis formation and tumor relapse after therapy.  相似文献   

10.
We have generated transgenic mice by introducing copies of the E. coli O6-methylguanine-DNA methyltransferase gene, ada. Liver extracts from homozygotes demonstrate about three times the control enzyme activity and increase up to about eight-fold can be induced by treatment with zinc, since the metal-responsive metallothionein promoter is attached to the ada gene. Furthermore, studies of liver carcinogenesis in our transgenic mice demonstrated significantly reduced rates of development of hepatocellular tumors after treatment with dimethylnitrosamine or diethylnitrosamine. It is well known that xeroderma pigmentosum (XP) patients are deficient in DNA repair. The availability of XPA (XP group A complementing) knockout mice has enabled us to investigate the functional role of the XPA nucleotide excision repair gene in carcinogenesis in vivo, first using the mouse skin as a model system. XPA-/- mice demonstrated skin ulcers 5-7 days after 7,12-dimethylbenz[a]anthracene (DMBA) treatment and papilloma development within 4 weeks prior to promotion, skin tumor incidence being also much higher than in heterozygous and wild-type mice. Experiments targeting the lung, liver and tongue have also been conducted to answer the question of whether the internal organs of these mice are also susceptible to chemical carcinogens. For lung carcinogenesis, mice were instilled intratracheally with a small dose of benzo[a]pyrene. The pulmonary tumor incidence in XPA-/- mice was significantly higher than in XPA+/- and XPA+/+ mice. XPA-/- mice were also found to be have enhanced sensitivity to aflatoxin B1 regarding liver tumor induction. In addition, administration of 4-nitroquinoline-1-oxide in drinking water for 50 weeks resulted in tongue tumors only in XPA-/- mice. These studies, thus, provided convincing evidence that XPA mice are also sensitive to carcinogenesis in organs other than the skin.  相似文献   

11.
Summary Use of the multicellular tumor spheroid as a tumor model allows separate host or tumor treatment with ionizing radiation and examination of the effects on host-tumor immune interactions. Spheroids of EMT6/Ro, a BALB/c mammary tumor were implanted into the peritoneal cavity of syngeneic immunized mice, recovered, and dissociated into single cells. Cytolytic activity of mature spheroid associated cells and peritoneal cells was resistant to radiation doses as high as 1000 rads when irradiated directly prior to assay. Mice irradiated (200, 400, 700 rads) 24 h prior to spheroid injection had an increased number of tumor cells and decreased number of tumor infiltrating and peritoneal host cells upon spheroid recovery. This was paralleled by an increased colony forming efficiency per spheroid. Cytolytic activity of the spheroid associated cells against radiolabeled EMT6 cells was in many cases decreased with radiation although lysis was the same on a per cell basis. Cytolytic activity by peritoneal cells from these mice increased with dose as measured on a per cell basis. This activity from irradiated animals was carried out by a Thyl+ cell.  相似文献   

12.
We have shown earlier that a decline in splenic natural killer (NK) activity during the development of transplanted or spontaneous tumors in mice results from an inactivation of NK lineage cells, mediated by prostaglandins (primarily PGE2) secreted by NK suppressor cells of the monocyte-macrophage lineage. In the present study we have used a C3H mouse mammary carcinoma model to examine whether this mechanism of NK suppression is conducive to tumor metastasis in vivo and whether a reversal of this suppression by a chronic indomethacin therapy can prevent metastatic spread from the primary tumor site. Three mammary tumor lines, all derived in our laboratory from a spontaneous C3H mammary tumor were employed: T-58 (uncloned parental line, having weak lung metastasizing ability from the subcutaneous site), C3 (a clone of T-58, showing high metastatic ability), and C10 (a nonmetastatic clone of T-58). Although the degree of NK susceptibility of these lines varied inversely with their metastatic potential, none was NK resistant. A chronic administration of indomethacin in the drinking water (14 micrograms/ml) to mice beginning on Day 4 after subcutaneous transplantation of 10(6) tumor cells resulted in a significant reduction in the growth rate of primary tumors in all hosts and led to a complete or nearly complete abrogation of lung metastasis in T-58- or C3-transplanted hosts examined at 1 month after tumor transplantation; C10-transplanted mice showed no metastasis in the control or the treated group. Concomitantly, there was a substantial restoration of splenic NK activity in all indomethacin-treated hosts. Plastic-adherent cells (greater than 95% macrophages) isolated from tumors growing in control mice, when coincubated for 20 hr with normal splenic effector cells caused a suppression of NK activity, reversible in the presence of indomethacin (10(-5) M) in vitro. Similar cells recovered from the residual primary tumors in indomethacin-treated mice had no suppressor ability. Chemically pure PGE2 (at concentrations of 0.5 to 1 X 10(-6) M, but not 0.25 X 10(-6) to 10(-8) M) also caused a suppression of NK activity of normal splenic effector cells, when added during the 4-hr 51Cr-release assay or allowed to interact with effector cells alone for a 20-hr incubation period; a removal of the cell-free PGE2 in the latter case prior to the NK assay did not relieve the suppression.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

13.
The A(2A) adenosine receptor plays a critical and non-redundant role in suppressing inflammation at sites of hypoxia and tissue damage. The tumor microenvironment has high levels of adenosine as a result of hypoxia and ectopic expression of enzymes responsible for the generation of extracellular adenosine. Thus, we sought to determine the ability of A(2A) receptor null mice to immunologically reject tumors. We observed that mice lacking the A(2A) adenosine receptor showed significantly delayed growth of lymphoma cells when compared to WT mice. Furthermore, when immunized with a low dose of tumor or with an irradiated GM-CSF-secreting tumor vaccine, A(2A) receptor null mice showed significantly enhanced protection from a subsequent high-dose challenge from both immunogenic and poorly immunogenic tumor lines. This increase in protection was accompanied by an increase in the number of tumor-antigen-specific CD8 T cells at the vaccine-site draining lymph node. Finally, we found that A(2A) receptor null mice displayed more robust anti-tumor responses than WT mice when they were treated with a soluble B7-DC/Fc fusion protein designed to antagonize B7-H1-mediated co-inhibition. This combinatorial immunotherapy strategy could also be recapitulated with pharmacological A(2A) receptor blockade paired with B7-DC/Fc administration. In light of these data, we believe that blockade of the A(2A) adenosine receptor is an attractive target for tumor immunotherapy that synergizes with other immunomodulatory approaches currently in clinical trials.  相似文献   

14.
Chromium(VI) is genotoxic when tested in vitro or injected parenterally in such a way to escape detoxification mechanisms. However, its genotoxicity and potential carcinogenicity are lost, depending on dose and administration route, due to efficient reduction in body fluids and nontarget cells. Chromium(VI) is a Group 1 IARC carcinogen, but only in the respiratory tract and in well-defined occupational settings that involved heavy exposures. Recently, concern has been expressed that oral chromium(VI) may be a gastric carcinogen. We demonstrated that administration of very high doses of chromium(VI) with the drinking water does not induce any clastogenic effect in hematopoietic cells of adult mice and their fetuses. Thereafter, we investigated whether administration of chromium(VI) with the drinking water may induce local genotoxic effects in the gastrointestinal tract. Sodium dichromate dihydrate was administered to mice for 9 consecutive months, at doses corresponding to 5 and 20 mg chromium(VI)/l, which exceed drinking water standards by 100 and 400 times, respectively. Under these conditions, chromium(VI) failed to enhance the frequency of DNA-protein crosslinks and did not cause oxidative DNA damage, measured in terms of 8-oxo-2'-deoxyguanosine, in the forestomach, glandular stomach and duodenum. When cells from the same organs were isolated and challenged in vitro with chromium(VI), as positive controls, the same genotoxicity biomarkers were evidently affected. Thus, consistently with the knowledge accumulated in 50 years of research on chromium(VI) kinetics and metabolism, oral chromium(VI) appears to be devoid of genotoxicity in the gastrointestinal tract. After 9 months, we did not observe any variation of tumor yield in skin, lung, forestomach, glandular stomach, and duodenum of chromium(VI)-treated mice. These results are discussed in the light of literature data, also including a recent 2-year carcinogenicity study performed by the National Toxicology Program.  相似文献   

15.
目的研究饮用经臭氧处理的灭菌水对小鼠自发性乳腺肿瘤发生的影响。方法给昆明(KM)小鼠、NIH小鼠和BALB/c小鼠饮用经臭氧处理的灭菌水,然后观察其乳腺肿瘤的发生情况,剖检小鼠并从其乳腺、左右肺叶、气管、肺门淋巴结、鼠蹊部淋巴结、心、肝、脾、肾、脑和大小肠等部位取材固定,常规病理制片进行病理组织学检查。结果饮用经臭氧处理的水数月后,KM小鼠、NIH小鼠和BALB/c小鼠,自发性乳腺肿瘤的数量明显增加。发生的乳腺肿瘤均为乳腺腺癌,其中一例为乳头状囊腺癌。乳腺肿瘤均发生在生育3~4胎以上的雌性小鼠。9例中有3例发生肺转移癌。根据乳腺肿瘤发生部位、大体形态特征及病理组织学,结合临床发病情况,即可明确诊断。结论长期饮用经臭氧处理的灭菌水可使小鼠自发性乳腺肿瘤的发生率明显上升。  相似文献   

16.
Inflammatory bowel disease (IBD) is a chronic recurrent disease of the digestive tract with an unknown etiology. The aim of this study was to examine the possible protective effects of N-acetylcysteine (NAC) in the mouse model of IBD by measuring specific biomarkers in the colon cells. Colitis was induced by administration of dextran sodium sulfate (DSS) in drinking water (3%) for 7 days. Three doses of NAC (106, 160, and 240 mg/kg) were given after induction of colitis (4 days post DSS) for 4 days by gavage. Lipid peroxides (LP), total antioxidant power (TAP), total thiol molecules (TTM), tumor necrosis factor-α (TNF-α), nitric oxide (NO), superoxide dismutase (SOD), and catalase (CAT) were measured in the colon homogenate of the treated animals. NAC (160 and 240 mg/kg) significantly decreased LP, TNF-α, NO and increased TTM, SOD, and CAT. The TAP was also increased by NAC (240 mg/kg). It is concluded that moderate to high doses of NAC improves cellular biomarkers of IBD in mice. Further studies should be trialled in humans suffering from two common inflammatory bowel disease called ulcerative colitis and Crohn’s disease.  相似文献   

17.
Historical accounts of alcohol administration to patients with breathing problems suggest that alcohol may have bronchodilating properties. We hypothesized that acute alcohol exposure will alter airway responsiveness (AR) in mice. To test this hypothesis, C57BL/6 mice were fed either 20% alcohol in drinking water (fed) or received a single intraperitoneal (ip) injection of alcohol (3 g/kg). Control groups received regular drinking water or ip saline. AR was assessed by means of ventilation or barometric plethysmography and reported as either total lung resistance or enhanced pause for each group of mice. To confirm alcohol exposure, elevated blood alcohol levels were documented. Alcohol feeding significantly blocked methacholine-triggered AR compared with water-fed controls. Comparable blunting of AR was also accomplished through a single ip injection of alcohol when compared with saline-injected controls. The alcohol response was slowly reversible in both routes of administration after withdrawal of alcohol: AR attenuation by alcohol persisted 12-20 h (ip) or up to 2 wk (fed) after blood alcohol cleared consistent with a sustained bronchodilator effect. These data demonstrate that brief alcohol exposure blunts AR in this murine model of alcohol exposure suggesting a role for alcohol in the modulation of bronchial motor tone.  相似文献   

18.
Grape seed proanthocyanidins (GSPs), a biologically active component of grape seeds, have been reported to possess a wide array of pharmacological and biochemical properties. Recently, the inhibitory effects of GSPs on various cancers have been reported, but their effects on cervical cancer remain unclear. Here, we explored the effect of GSPs on cervical cancer using in vitro and in vivo models. In vitro, the treatment of HeLa and SiHa cells with GSPs resulted in a significant inhibition of cell viability. Further investigation indicated that GSPs led to the dose-dependent induction of apoptosis in cancer cells. The underlying mechanism was associated with increased expression of the pro-apoptotic protein Bak-1, decreased expression of the anti-apoptotic protein Bcl-2, the loss of mitochondrial membrane potential, and the activation of caspase-3, suggesting that GSPs induced cervical cancer cell apoptosis through the mitochondrial pathway. In addition, the administration of GSPs (0.1%, 0.2%, and 0.4%, w/v) as a supplement in drinking water significantly inhibited the tumor growth of HeLa and SiHa cells in athymic nude mice, and the number of apoptotic cells in those tumors was also increased significantly. Taken together, our studies demonstrated that GSPs could inhibit the growth of cervical cancer by inducing apoptosis through the mitochondrial pathway, which provides evidence indicating that GSPs may be a potential chemopreventive and/or chemotherapeutic agent for cervical cancer.  相似文献   

19.
Some species of lactic acid bacteria have been shown to be beneficial in inflammatory bowel disease (IBD). In the present study, a strain of lactic acid bacterium (Lactobacillus paracasei LS2) was isolated from the Korean food, kimchi, and was shown to inhibit the development of experimental colitis induced by dextran sulfate sodium (DSS). To investigate the role of LS2 in IBD, mice were fed DSS in drinking water for seven days along with LS2 bacteria which were administered intragastrically to some of the mice, while phosphate-buffered saline (PBS) was administered to others (the controls). The administration of LS2 reduced body weight loss and increased survival, and disease activity indexes (DAI) and histological scores indicated that the severity of colitis was significantly reduced. The production of inflammatory cytokines and myeloperoxidase (MPO) activity also decreased. Flow cytometry analysis showed that the number of Th1 (IFN-γ) population cells was significantly reduced in the LS2-administered mice compared with the controls. The administration of LS2 induced the increase of CD4+FOXP3+ Treg cells, which are responsible for IL-10. Numbers of macrophages (CD11b+ F4/80+), and neutrophils (CD11b+ Gr-1+) among lamina propria lymphocytes (LPL) were also reduced. These results indicate that LS2 has an anti-inflammatory effect and ameliorates DSS-induced colitis.  相似文献   

20.
The objective of the present investigation was to examine the effects of an irreversible inhibitor of ornithine decarboxylase (2R,5R)-6-heptyne-2,5,diamine (methylacetylenic putrescine, MAP) on experimentally induced arthritis in mice. MAP (0.5-0.05%) was administered in drinking water to DBA/1 mice immunized with native chick type II collagen (CII). The development of arthritis was inhibited only in those mice receiving 0.5% MAP; lower doses were ineffective. Putrescine and spermidine levels were decreased and spermine levels were increased in spleen and lymph node cells from drug-treated mice compared to control arthritic mice. Furthermore, when control mice were developing arthritis, serum anti-CII antibody levels were lower in the MAP-treated group. MAP inhibited antibody production early in the immune response to CII; there was an association between inhibition of antibody production and inhibition of the development of arthritis. When MAP was discontinued, the nonarthritic, drug-treated mice did not develop the disease. Late administration of MAP (beginning 19 days after CII immunization) did not affect the incidence or the severity of the arthritis. Cyclophosphamide treatment begun at the same time significantly inhibited the development of the disease. In vitro T cell responses to denatured type II collagen (dCII) in untreated and MAP-treated mice were examined 14 days after immunization with CII. This is a time of peak T cell responsiveness in untreated animals. MAP treatment had no effect on the T cell response to dCII. These results indicate that MAP can prevent the development of CII-induced arthritis, possibly by inhibiting the autoantibody response. Therefore, inhibitors of polyamine biosynthesis deserve further investigation as potential immunosuppressive agents.  相似文献   

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