敌匹硫磷对Balb/c小鼠免疫功能影响

目的 观察敌匹硫磷对小鼠细胞免疫功能和体液免疫功能的影响。方法 将敌匹硫磷以1.6,3.2,6.3,12.5和25 mg/kg剂量灌胃染毒小鼠,4周后观察小鼠免疫功能的变化。采用T淋巴细胞增殖和迟发型变态反应来评价细胞免疫功能,采用血清溶血素测定和抗体生成细胞检测来评价体液免疫功能,采用乳酸脱氢酶法测定自然杀伤细胞(NK细胞)活性来评价非特异性免疫功能。结果 敌匹硫磷染毒4周后,6.3 mg/kg组小鼠的体液免疫功能和迟发型变态反应受到抑制;12.5,25 mg/kg组小鼠的胸腺脏器系数均降低20%,抗体生成细胞数分别降低39%和52%,血清溶血素水平分别降低15%和20%,迟发型变态反应水平分别降低33%和35%,淋巴细胞增殖能力分别下降27%和35%,NK细胞活性分别下降24%和28%。结论 敌匹硫磷对Balb/c小鼠的体液免疫功能、细胞免疫功能以及非特异性免疫功能均有抑制作用,体液免疫功能对其毒性更为敏感。     

Vaccination of Balb/c mice against enteroviral mediated myocarditis

A non-virulent strain of Coxsackie B3 (CB3) virus was used to produce a subunit vaccine. It contains the capsid proteins VP1, 2, 3 and probably 4 and can be made RNA-free. It is based on the ISCOM technology ensuring non-toxic properties and good adjuvant effect. Vaccinated animals at doses above 16 ng were completely protected from mortality when challenged with a myocarditic strain of CB3. Histologically no inflammatory lesions were found in the heart. This was corroborated using immune histological techniques with monoclonal antibodies against lymphocyte subsets. Even at a dose of 0.16 ng a delayed mortality was observed. Neutralizing antibody titres rose to 512, thus ensuring a circulating level well above that considered protective. It is suggested that vaccination might be a possible way of prophylaxis for myocarditis and even dilated cardiomyopathy, the latter presently being the chief cause of heart transplantation. By persistence or triggering of autoimmune phenomena Coxsackie virus is incriminated as the first step in pathogenesis.     

Antioxidative and hepatoprotective effects of fructo-oligosaccharide in d-galactose-treated Balb/cJ mice

Chronic subcutaneous (s.c.) administration of d-galactose (DG) to BL/6J mice has been shown to induce oxidative stress and is considered a model to mimic accelerated ageing. Fructo-oligosaccharide (FO) is a well-defined prebiotic and its fermentation by lactic acid bacteria has been shown to exert antioxidative capacity. The present study was aimed to determine whether FO attenuated DG-induced oxidative stress and hepatopathy in Balb/cJ mice. Mice (12 weeks of age, n 40) were divided into control (s.c. saline), DG (s.c. 1·2 g/kg body weight), DG+FO (5%, w/w) and DG+vitamin E (0·2%, w/w) groups and were killed after 52 d of treatment. Results indicated that DG significantly decreased the hepatic superoxide dismutase and glutathione peroxidase activities. These alterations were ameliorated both by FO and vitamin E. DG increased the hepatic TAG content approximately by 7·2% compared with the vehicle control, which was in agreement with the histological alteration. FO, similar to vitamin E, almost normalised the hepatic TAG content and ameliorated the histological characteristics of fatty liver. Similarly, the increased plasma alanine aminotransferase activity induced by DG was normalised by FO and vitamin E, respectively. Faecal bifidobacteria counts were greater in the DG+FO and DG+vitamin E groups compared with the DG group, respectively. In conclusion, the present study indicated that FO diminished the altered hepatic antioxidative enzyme activities and morphology caused by chronic DG administration in Balb/cJ mice, partially associated with its prebiotic role in the colon.     

Unhydrolyzed and hydrolyzed konjac glucomannans modulated cecal and fecal microflora in Balb/c mice

OBJECTIVE: The prebiotic role of intact konjac glucomannan (KGM) is contradictory. Short-chain glucomannan may cause a greater or faster effect on colonic microflora compared with KGM. Therefore, time-course and dose-dependent studies were conducted to examine and compare effects of unhydrolyzed KGM with those of acid-hydrolyzed glucomannan (KH) on cecal and fecal microflora. Short-chain fatty acid concentrations in cecal content were also determined. METHODS: Seven-week-old male Balb/c mice were fed 5% (w/w) cellulose and KGM or KH diets for 2 or 4 wk in a time-course study. Cecal total anaerobes, bifidobacteria, Clostridium perfringens and Escherichia coli counts, and short-chain fatty acid concentrations were determined. In a subsequent dose-dependent study, Balb/c mice were fed AIN-93 fiber-free diets supplemented with 2.5%, 5%, or 7.5% of KGM or KH for 4 wk. Anaerobes, bifidobacteria, C. perfringens, and E. coli were enumerated in the cecal content and feces. RESULTS: KGM and KH significantly increased cecal anaerobes and bifidobacteria counts at weeks 2 and 4, respectively, compared with cellulose. In contrast, KGM and KH significantly decreased cecal C. perfringens counts only at week 4. Acetate and propionate concentrations in cecal contents were increased by KGM and KH diets at weeks 2 and 4, respectively. In the dose-dependent study, KH increased cecal bifidobacteria counts only at the 2.5% level but increased fecal bifidobacteria count and suppressed C. perfringens counts at each dose level as compared with KGM. CONCLUSION: Hydrolyzed glucomannan exerts a greater prebiotic effect than does KGM in Balb/c mice.     

Effects of calcium phosphate supplementation on calcium,phosphorus, and magnesium metabolism in the Wistar rat

Calcium supplementation has been used in humans and in experimental animals to retard bone loss and lower blood pressure, but there are few data in regard to the metabolic effects of supplementation. This study evaluated the impact of supplementing the AIN-76 diet with various amounts of CaHPO₄ on food intake, growth, Ca, Mg and P balance and serum and bone concentrations of these nutrients. Four groups of nine 5-wk old normal male Wistar rats were fed ad libitum for 12 wks the AIN-76 semi-purified diet either unsupplemented (nominally 0.5% Ca), or supplemented to approximately 1.0%, 1.4% or 2.2% Ca with CaHPO₄. Another group of five rats was fed Rat Chow^®. Addition of CaHPO₄ did not alter intake of other nutrients. Dietary Ca level had no effect on whole blood or plasma ionized Ca, plasma total Ca or plasma P in fasted animals, whereas plasma Mg tended to decline with increased Ca supplementation. Increased Ca balance followed CaHPO₄ supplementation, whereas Mg balance declined. P balance was positive and similar in all study groups. Femur dry weight and length did not differ with diet nor did bone Ca content increase with supplementation. Bone Mg content decreased with CaHPO₄ supplementation. The results indicate that ingestion of CaHPO₄ in supplementary amounts does not increase bone Ca in the young normal rat but it is accompanied by other metabolic changes, particularly a striking decrease in net absorption of Mg.     

Oral administration of HPV-16 L2 displayed on Lactobacillus casei induces systematic and mucosal cross-neutralizing effects in Balb/c mice

The human papillomavirus (HPV) minor capsid protein, L2, is a good candidate for prophylactic vaccine development because L2-specific antibodies have cross-neutralizing activity against diverse HPV types. Here, we developed a HPV mucosal vaccine candidate using the poly-γ-glutamic acid synthetase A (pgsA) protein to display a partial HPV-16 L2 protein (N-terminal 1-224 amino acid) on the surface of Lactobacillus casei (L. casei). The oral immunization with L. casei-L2 induced productions of L2-specific serum IgG and vaginal IgG and IgA in Balb/c mice. To examine cross-neutralizing activity, we used a sensitive high-throughput neutralization assay based on HPV-16, -18, -45, -58, and bovine papillomavirus 1 (BPV1) pseudovirions. Our results revealed that mice vaccinated with L. casei-L2 not only generated neutralizing antibodies against HPV-16, but they also produced antibodies capable of cross-neutralizing the HPV-18, -45, and -58 pseudovirions. Consistent with previous reports, vaccination with HPV-16 L1 virus-like particles (VLPs) failed to show cross-neutralizing activity. Finally, we found that oral administration of L. casei-L2 induced significant neutralizing activities against genital infection by HPV-16, -18, -45, and -58 pseudovirions encoding a fluorescence reporter gene. These results collectively indicate that oral administration of L2 displayed on L. casei induces systemic and mucosal cross-neutralizing effects in mice.     

Canthaxanthin supplementation alters antioxidant enzymes and iron concentration in liver of Balb/c mice

The 4,4'-diketo-beta-carotene, canthaxanthin, alters tocopherol status when fed to Balb/c mice, suggesting an involvement of carotenoids in the modulation of oxidative stress in vivo. We investigated further the modifications induced by an oral administration of canthaxanthin on lipid peroxidation, antioxidant enzymes and iron status in liver of Balb/c mice. Female 6-wk-old Balb/c mice were randomly divided into two groups (n = 10/group). The control group (C) received olive oil alone (vehicle) and the canthaxanthin-treated group (Cx) received canthaxanthin at a dose of 14 microg/(g body wt.d). The 15-d canthaxanthin treatment resulted in carotenoid incorporation but did not modify lipid peroxidation as measured by endogenous production of malondialdehyde (MDA). However, glutathione peroxidase activity was 35% lower (P<0.01) and catalase (59%, P<0.005) and manganese superoxide dismutase (MnSOD) (28%, P<0.05) activities were higher in canthaxanthin-treated mice than in controls. Moreover, carotenoid feeding caused a significant (P<0.05) overexpression of the MnSOD gene; mRNA levels of the enzyme were greater in treated mice than in controls. Concomitantly, a 27% (P<0.05) greater iron concentration was found in liver from canthaxanthin-treated mice compared with controls. These findings support the hypothesis that canthaxanthin alters the protective ability of tissues against oxidative stress in vivo.     

Influence of age and magnesium on calcium metabolism in rats

This study evaluates the effect of dietary magnesium concentration on calcium metabolism in rats of differing ages. Young (3 wk) and old (18 mo) Fischer 344 rats were fed the AIN-76A diet modified to contain either low (218 mg/kg) or adequate (419 mg/kg) Mg for 4 wk. Some rats subsequently underwent a metabolic balance study (12 d duration). Other rats were gavaged with approximately 220 KBq (6 microCi) of 47Ca; daily fecal and urine collections were made and periodic whole body radioactivity determined. Femurs were removed and analyzed. Calcium retention and balance were not affected by Mg in young rats. In old rats low Mg intake increased apparent Ca balance. Young rats retained about 3.25 times more of the original dose of 47Ca than did old rats. Young rats retained more 47Ca in the femur than did old rats; Mg intake had little effect. Aging accelerated Ca turnover rate, and whole body retention data suggest that adequate Mg does not significantly reduce Ca turnover.     

苦瓜素对小鼠柯萨奇B3病毒性心肌炎caspase 3作用的研究

目的观察苦瓜素对病毒性心肌炎心肌组织caspase 3活性、基因转录及相应蛋白质表达的影响,探索苦瓜素治疗病毒性心肌炎的机制。方法实验小鼠随机分为苦瓜素治疗组、生理盐水对照组及正常对照组和正常小鼠苦瓜素处理组。苦瓜素剂量为25 mg.kg-1.d-1,1次/d,疗程7 d。第15天后取小鼠心肌进行caspase 3活性测定、HE染色心肌病理检查、心肌细胞凋亡检查、RT-PCR检测、caspase 3,mRNA转录水平,免疫组化与免疫印迹测定caspase 3蛋白表达。结果生理盐水对照组小鼠心肌组织caspase 3活性明显增高、mRNA转录水平与相应蛋白质表达水平亦显著增加;苦瓜素治疗组caspase 3活性明显抑制,caspase 3 mR-NA转录水平明显低于生理盐水对照组(0.012±0.008 vs 0.043±0.015,t=4.37,P<0.01),凋亡细胞明显减少。结论苦瓜素通过抑制caspase 3基因转录与蛋白质表达、抑制其活性,对Balb/c小鼠CVB3病毒性心肌炎具有明显的治疗作用。     

藏红花素对K562细胞株及裸鼠移植瘤的抑制作用的研究

目的探讨藏红花素对K562细胞株及裸鼠移植瘤的作用。方法利用MTT法检测不同浓度藏红花素对K562细胞的增殖抑制影响;Annexin V-FITC标记法检测K562细胞凋亡;建立K562细胞Balb/c裸鼠皮下移植瘤模型,荷瘤小鼠随机分成4组,分别用10、50、100 mmol/L浓度的藏红花素和生理盐水对瘤体进行局部注射,每次0.1 ml,隔日1次,连续7次,观察瘤体变化。结果不同浓度藏红花素对K562细胞均有抑制作用,呈明显的剂量依赖性,抑制率分别为21.5%、55.1%、81.6%(P<0.05);浓度为0.003 2 mol/L的藏红花素诱导K562细胞凋亡作用最显著,浓度为6.4 mmol/L的藏红花素使K562细胞呈中毒反应,凋亡作用不明显;藏红花素组瘤体生长较对照组明显受到抑制,不同浓度的藏红花素抑瘤率分别为18.5%、79.2%、91.6%。结论藏红花素具有显著抑制K562细胞增殖及促凋亡的作用,能有效抑制K562细胞Balb/c裸鼠移植瘤的生长。     

Enhancement of 1,2-dimethylhydrazine-induced large bowel tumorigenesis in Balb/c mice by corn, soybean, and wheat brans

This study was designed to determine the effects of four well-characterized dietary brans on large bowel tumorigenesis induced in mice with 1,2-dimethylhydrazine (DMH). Eight-week-old barrier-derived male Balb/c mice were fed a semisynthetic diet with 20% bran added (either corn, soybean, soft winter wheat, or hard spring wheat) or a no-fiber-added control diet. Half of each group was given DMH (20 mg/kg body weight/week, subcutaneously for 10 weeks) beginning at 11 weeks of age. Surviving mice were killed 40 weeks after the first DMH injection. Tumors were not found in mice not subjected to DMH. In DMH-treated mice, tumors were found almost exclusively in the distal colon. Tumor incidences were as follows: controls, 11%; soybean group, 44%; soft winter wheat group, 48%; hard spring wheat group, 58%; and corn group, 72%. Tumors per tumor-bearing mouse ranged from 1.4 to 1.6, except in the corn group, which had 2.1. A positive correlation was found between percentage of neutral detergent fiber in the brans and tumor incidences but not between the individual components of cellulose, hemicellulose, or lignin. The enhancement of DMH-induced large bowel tumorigenesis by all four bran types may reflect a species and/or mouse strain effect that is bran-source related. These data emphasize the importance of using well-defined bran in all "fiber" studies.     

Effects of Taiwanese yam (Dioscorea japonica Thunb var. pseudojaponica Yamamoto) on upper gut function and lipid metabolism in Balb/c mice

OBJECTIVE: This study investigated the effects of a Taiwanese yam, Dioscorea japonica Thunb var. pseudojaponica Yamamoto, on upper gut function and lipid metabolism in adult Balb/c mice. METHODS: Mice were randomly allocated to consume the control, 25%, or 50% yam diet in which yam in an uncooked lyophilized form was incorporated into the diet for 21 d. RESULTS: Growth rates were similar among groups, even though the apparent protein absorption rate was decreased by the 50% yam diet. Both yam diets decreased gastric villous width but did not significantly modulate other morphologic and proliferative indices. Brush-border leucine aminopeptidase activities in the small intestine were increased approximately 30% by the 25% and 50% yam diets, respectively. In contrast, sucrase activity was decreased 40% by the 25% yam diet and 50% by the 50% yam diet. The 50% yam diet consistently improved the cholesterol profile in the plasma and liver, whereas the 25% yam diet reduced only the level of low-density lipoprotein cholesterol in plasma. Changes in blood lipid levels were associated with reduced fat absorption. CONCLUSION: A 25% uncooked yam diet may benefit upper gut function and prevent hypercholesterolemia in humans, but the 50% yam diet negatively affected protein absorption.     

Immunogenicity and anti-Burkholderia pseudomallei activity in Balb/c mice immunized with plasmid DNA encoding flagellin

Plasmid DNA encoding the flagella protein (flagellin) was used as a vaccination candidate for the evaluation of its immunogenicity and for protection against infection with Burkholderia pseudomallei. Firstly, flagellin encoding plasmid DNA was injected into Balb/c mice intramuscularly and this elicited both a humoral and a cellular immune response. Total IgG production and the clonal expansion of the spleen cells increased in response to flagellin. The IgG subclass response exhibited a dominance of IgG2a over IgG1 in the sera. In addition, IFN-gamma-secreting cells in the spleen were substantially increased. Furthermore, the anti-B. pseudomallei activity of the peritoneal exudate cells was evaluated by a Transwell tissue-culture plate system where the macrophage-activating related cytokines in upper chamber were allowed to cross the plate's membrane and stimulate the activation of peritoneal exudate cells in lower chamber. Our results indicated that the activated peritoneal exudate cells were able to restrict the growth of B. pseudomallei in vitro. Indeed, subsequent intravenous challenge of the vaccinated Balb/c mice with 10(5)CFU of B. pseudomallei resulted in the number of bacterial cells detected in liver and/or spleen being significantly reduced in the flagellin plasmid DNA vaccinated mice. At 7 days subsequent to infection of B. pseudomallei, 5/6 (83%) of flagellin plasmid DNA vaccinated mice had survived. We suggest that plasmid DNA-encoding flagellin might be useful as a potential immunization route for the future development of a vaccine against melioidosis in related animals.     

Zinc metabolism in genetically obese (ob/ob) mice

Recent reports indicate that the concentrations and total amounts of several essential trace metals in various tissues of genetically obese rodents differ markedly from those in lean controls. In the present studies the absorption, retention and tissue distribution of zinc and constitutive levels of zinc-metallothionein (Zn-MT) in selected tissues were compared in obese (ob/ob) and lean (+/?) C57BL/6J mice. When 5-, 10- and 22-wk-old mice were administered 1.2 mumol 65Zn by stomach tube the apparent absorption of 65Zn by obese mice was 1.5, 2.2 and 3.9 times higher, respectively, than that in age-matched lean mice. Retention of orally administered 65Zn after 96 h was also substantially higher in obese mice than in lean mice. To assess the possible influences of hyperphagia and intestinal hypertrophy on the enhanced apparent absorption of 65Zn by obese mice food intake by an additional group of obese mice was restricted to that of age-matched lean controls. When actual absorption of zinc was determined according to the method of Heth and Hoekstra, groups of ad libitum--fed obese, pair-fed obese and lean mice absorbed 38, 32 and 18% of administered 65Zn, respectively. In contrast, the rate of 65Zn excretion 2-6 d after oral or subcutaneous administration of the metal was similar for obese and lean mice. Unrestricted and pair-fed obese mice had significantly lower percentages of carcass 65Zn present in skin, muscle plus bone, spleen and testes and higher percentages present in liver, small intestine and adipose tissue than lean mice.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of calcium-enriched high-fat diet on calcium, magnesium and zinc retention in mice

The aim of this work was to assess the effects of a high-fat diet enriched in Ca, which accompanies lower body fat deposition, on mineral depots, as well as to assess the potential role of adaptive thermogenesis in mice. Male mice were fed ad libitum a high-fat (43 %) diet with a Ca content of 4 g/kg from calcium carbonate (control group) or 12 g/kg (42 % from milk powder and the rest from calcium carbonate) (Ca group) for 56 d. Body weight, food intake and urine were periodically collected. Tissue samples were collected when the mice were killed and the composition was determined. Expression of uncoupling proteins was determined by Western blotting. Mineral content was measured by flame atomic absorption spectrometry. Lower body weight gain and fat accretion was found in the Ca group. This could not be attributable to lower gross energy intake or to activation of adaptive thermogenesis. Although significant urine mineral loss was found in the Ca group, preservation of mineral depots in bone was observed. Our data support the fact that adding more Ca to the diet, using a combination of calcium carbonate plus milk powder containing among other things higher Zn and Mg, contributes to counteracting obesity and improving lipid metabolism.     

Whole body exposure to low-dose gamma radiation promotes kidney antioxidant status in Balb/c mice

We examined the effect of whole body low-dose gamma-irradiation on the status of the antioxidant defense system in the rodent kidneys at different time intervals. Young male Balb/c mice were exposed to whole body radiation from a (60)Co source at doses of 10, 25 and 50 cGy (48.78 cGy/min). Antioxidant status and lipid peroxidation were estimated in the kidneys at 4, 12 and 24 h after irradiation. Lipid peroxidation increased between 33% and 49% and reduced glutathione between 12% and 47% at 12 h at different radiation doses. Reduced glutathione level remained significantly (p < 0.05) elevated even at 24 h after irradiation to 25 cGy. Superoxide dismutase activity also increased by 37% at 12 h on exposure of animals to all the doses up to 50 cGy. Catalase activity increased significantly at 12 h on exposure to 10 cGy and 50 cGy. Interestingly, glutathione peroxidase activity increased by 31% at 4 h and subsequently returned to control levels at 24 h after exposure to 50 cGy. Glutathione reductase activity increased by 10-12% at 12 h after exposure to 25 cGy and 50 cGy. The results suggest that the whole body exposure of animals to gamma radiation stimulates the antioxidant defense system in the kidneys within 4 to 24 h after irradiation, at doses of 25 cGy and 50 cGy.     

Vitamin D deficiency enhances the growth of MC-26 colon cancer xenografts in Balb/c mice

Vitamin D deficiency has been associated with increased risk of colon cancer in epidemiologic and prospective clinical studies. In vitro and in vivo studies demonstrated that 1,25-dihydroxycholecalciferol [1,25(OH)2D3] and its analogs inhibit colon cancer cell proliferation. Few studies have evaluated the effect of vitamin D deficiency on the development and growth of colon cancer. To assess the antiproliferative effects of 25-hydroxyvitamin D [25(OH)D] and 1,25(OH)2D3 in vitro, we cultured MC-26 (a colon cancer cell line) in the presence of 25(OH)D3 and 1,25(OH)2D3 and performed [3H]thymidine incorporation. The proliferation of MC-26 was significantly inhibited by both 25(OH)D3 and 1,25(OH)2D3. To determine the effect of vitamin D deficiency on colon cancer proliferation, Balb/c mice were rendered vitamin D deficient by feeding them a vitamin D-deficient diet for 3 mo. A group of vitamin D-sufficient mice was given the same diet with supplemental vitamin D. The mice were injected with MC-26 colon cancer cells and the tumors were measured daily for 20 d. Vitamin D-sufficient mice had 40% smaller tumors than vitamin D-deficient mice. The tumors were evaluated for mRNA expression of the vitamin D receptor (VDR) and 25-hydroxvitamin D-1alpha-hydroxylase (1alpha-OHase) by quantitative RT-PCR. The expression of the mRNA for the VDR and the 1alpha-OHase was 37- and 6-fold higher, respectively, in the vitamin D-sufficient mice compared with the vitamin D-deficient mice. We conclude that vitamin D deficiency enhances the growth of colon cancer in mice. The tumor expression of VDR and 1alpha-OHase indicates possible autocrine/paracrine cell growth regulation by vitamin D.     

Calcium supplements and milk: effects on acid-base balance and on retention of calcium, magnesium, and phosphorus

The effect of supplementing a basal diet containing 697 mg calcium daily (17.4 mmol/d) with an additional 900 mg Ca daily from milk, Ca chloride, or a Ca carbonate preparation was examined in eight adult males during a 56-d metabolic balance study. The ingestion of the milk or Ca supplements had no overall effect on Ca retention by these subjects because the milk and supplements depressed apparent absorption of Ca in the gut and fractional tubular reabsorption of Ca in the kidneys. Supplementation of the diet with CaCl and to a lesser extent with milk significantly increased renal acid excretion whereas supplementation with CaCO3 depressed renal acid excretion. The three Ca supplements significantly altered magnesium and phosphorus absorption and urinary excretion in different manners but had no overall effect on retention of P or Mg. The responses of our subjects to these treatments may be different than those of subjects who are chronically in negative balance in regard to Ca.