共查询到20条相似文献,搜索用时 62 毫秒
1.
Huawei Zeng Eric O. Uthus Sharon A. Ross Cindy D. Davis 《Biological trace element research》2009,131(1):71-80
Our previous studies have shown that selenium (Se) is protective against dimethylhydrazine (DMH)-induced preneoplastic colon
cancer lesions, and protection against DNA damage has been hypothesized to be one mechanism for the anticancer effect of Se.
The present study was designed to determine whether dietary selenite affects somatic mutation frequency in vivo. We used the
Big Blue transgenic model to evaluate the in vivo mutation frequency of the cII gene in rats fed either a Se-deficient (0 μg Se/g diet) or Se-supplemented diet (0.2 or 2 μg Se/g diet; n = 3 rats/diet in experiment 1 and n = 5 rats/group in experiment 2) and injected with DMH (25 mg/kg body weight, i.p.). There were no significant differences
in body weight between the Se-deficient and Se-supplemented (0.2 or 2 μg Se/g diet) rats, but the activities of liver glutathione
peroxidase and thioredoxin reductase and concentration of liver Se were significantly lower (p < 0.0001) in Se-deficient rats compared to rats supplemented with Se. We found no effect of dietary Se on liver 8-hydroxy-2′-deoxyguanosine.
Gene mutation frequency was significantly lower in liver (p < 0.001) than that of colon regardless of dietary Se. However, there were no differences in gene mutation frequency in DNA
from colon mucosa or liver from rats fed the Se-deficient diet compared to those fed the Se-supplemented (0.2 or 2 μg Se/g
diet) diet. Although gene mutations have been implicated in the etiology of cancer, our data suggest that decreasing gene
mutation is not likely a key mechanism through which dietary selenite exerts its anticancer action against DMH-induced preneoplastic
colon cancer lesions in a Big Blue transgenic rat model.
The US Department of Agriculture, Agricultural Research Service, Northern Plains Area, is an equal opportunity/affirmative
action employer and all agency services are available without discrimination.
Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the US Department
of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable.
This work was supported by the US Department of Agriculture and National Cancer Institute. 相似文献
2.
We report here some results of a long-term (19 month) study with cats fed methylmercury (MeHg) in nutritionally balanced diets
based on fish. By using either freshwater pike (low in Se) or canned tuna (high in Se) as the major protein source, basal
diets with low levels of MeHg were prepared having different Se content, all Se being of natural origin. The basal diets produced
no signs of toxicity or pathological changes over the l9-month period. In cats fed basal diets spiked with medium or high
levels of MeHg, evidence for delayed onset of toxic effects from the added MeHg was observed with the tuna diets compared
to pike diets. In brain, muscle, and blood, the activity of GSH peroxidase, a selenoenzyme, was decreased by Hg. In liver,
substantial accumulation of Hg with Se occured (molar Hg/Se ratio approximately 1.4 to 1.8) but GSH peroxidase activity was
unaffected. We suggest that the coaccumulation of Hg and Se in liver measures the extent to which MeHg has been metabolically
transformed by metabolism to Hg++, and inactivated by deposition as a Hg/Se complex of low bioavailability. The accumulation
of Hg and Se in liver was much greater in cats fed tuna compared to pike, out of proportion to the relatively small differences
in Hg and Se content of the tuna and pike basal diets. Some mechanisms are described by which selenium, vitamin E, and other
factors might facilitate MeHg breakdown to inorganic Hg during long term low level exposure to MeHg. 相似文献
3.
To investigate the role of selenium (Se) in the developing porcine fetus, prepubertal gilts (n=42) were randomly assigned to either Se-adequate (0.39 ppm Se) or Se-deficient (0.05 ppm Se) gestation diets 6 wk prior to
breeding. Maternal and fetal liver was collected at d 30, 45, 70, 90, and 114 of pregnancy. Concentrations of Se in maternal
liver decreased during gestation in gilts fed the low-Se diet. The activity of cellular glutathione peroxidase (GPx) was decreased
at d 30 and 45 of gestation in liver of gilts fed the low-Se diet. Concentrations of malondialdehyde (MDA) and hydrogen peroxide
(H2O2) were greater in liver homogenates from gilts fed the low-Se diet. Within the fetuses, liver Se decreased in those fetuses
of gilts fed the low-Se diet. Although the activity of GPx in fetal liver was not affected by the maternal diet, concentrations
of H2O2 and MDA in fetal liver were greater in fetuses from gilts fed the low-Se diet. Maternal liver GPx activity was approx 12-fold
greater than fetal liver GPx activity regardless of dietary treatment. These results indicate that maternal dietary Se intake
affects fetal liver Se concentration and feeding a low-Se diet during gestation increases oxidative stress to the fetus, as
measured by fetal liver H2O2 and MDA. 相似文献
4.
Cell culture studies have suggested that arsenic exposure results in decreased S-adenosylmethionine (SAM), causing DNA hypomethylation. Previously, we have shown that hepatic SAM is decreased and/or S-adenosylhomocysteine increased in arsenic-deprived rats; these rats tended to have hypomethylated DNA. To determine, the
effect of dietary arsenic on dimethylhydrazine (DMH)-induced aberrant crypt formation in the colon, Fisher 344 weanling male
rats were fed diets containing 0,05, or 50 μg As (as NaAsO2)/g. After 12 wk, dietary arsenic affected the number of aberrant crypts (p<0.02) and aberrant crypt foci (p<0.007) in the colon and the amount of global DNA methylation (p<0.04) and activity of DNA methyltransferase (DNMT) (p<0.003) in the liver. In each case, there were more aberrant crypts and aberrant crypt foci, a relative DNA hypomethylation,
and increased activity of DNMT in the rats fed 50 μg As/g compared to those fed 0.5 μg As/g. The same phenomenon, an increased
number of aberrant crypts and aberrant crypt foci, DNA hypomethylation, and increased DNMT tended to hold when comparing rats
fed the diet containing no supplemental arsenic compared to rats fed 0.5 μg As/g. The data suggest that there is a threshold
for As toxicity and that possibly too little dietary As could also be detrimental.
The U.S. Department of Agriculture, Agricultural Research Service. Northern Plains Area is an equal opportunity/affirmative
action employer and all agency services are available without discrimination. 相似文献
5.
6.
The influence of dietary copper, iron, and ascorbic acid on iron utilization was examined in a 2×2×2 factorial experiment.
Male Sprague-Dawley weanling rats were fed copper-deficient (Cu-, 0.42 μg Cu/g) or copper-adequate (Cu+, 5.74 μg Cu/g) diets
that contained one of two levels of iron (38 or 191μg Fe/g) and ascorbic acid (0 or 1% of the diet). These eight diets were
fed for 20 d, and rats received an oral dose of 4 μCi iron-59 on d 15. Compared to Cu+ rats, the Cu− rats had 27% lower hemoglobin
levels with 45, 59, and 65% lower cytochrome c oxidase (CCO) activities in the liver, heart, and bone marrow, respectively
(p<0.0001). High dietary iron or ascorbic acid did not alter hemoglobin in Cu+ rats. However, hemoglobin was 23% lower in Cu−
rats fed the highest, rather than the lowest levels of iron and ascorbic acid. Liver CCO was decreased (p<0.02) in Cu− rats fed high iron. Among Cu− rats, ascorbic acid did not influence CCO but decreased hemoglobin by 17% (p<0.001), reduced the percentage of absorbed iron-59 in the erythrocytes by 91% (p<0.05) and depressed the percentage apparent absorption of iron (p<0.05). These results suggest that the effects of elevated dietary iron and ascorbic acid on iron utilization are influenced
by copper status. 相似文献
7.
Nicholas V. C. Ralston 《EcoHealth》2008,5(4):442-455
Selenium (Se) is absolutely required for activity of 25–30 genetically unique enzymes (selenoenzymes). All forms of life that
have nervous systems possess selenoenzymes to protect their brains from oxidative damage. Homeostatic mechanisms normally
maintain optimal selenoenzyme activities in brain tissues, but high methylmercury (MeHg) exposures sequester Se and irreversibly
inhibit selenoenzyme activities. However, nutritionally relevant amounts of Se can replace the Se sequestered by MeHg and
maintain normal selenoenzyme activities, thus preventing oxidative brain damage and other adverse consequences of MeHg toxicity.
Findings of studies that seem contradictory from MeHg exposure perspectives are entirely consistent from MeHg:Se molar ratio
perspectives. Studies that have reported dose-dependent consequences of maternal MeHg exposures on child development uniformly
involved seafoods that contained much more Hg than Se. Meanwhile more typical varieties of ocean fish contain much more Se
than Hg. This may explain why maternal MeHg exposure from eating ocean fish is associated with major IQ benefits in children
instead of harm. Therefore, instead of being avoided, ocean fish consumption should be encouraged during pregnancy. However,
the safety of freshwater fish consumption is less certain. In freshwater fish, MeHg bioaccumulation and toxicity are both
inversely related to Se bioavailability. Their Se can be far lower than their MeHg contents, potentially making them more
dangerous than pilot whale meats. Therefore, to provide accurate and appropriate regulatory advice regarding maternal consumption
of seafoods and freshwater fish, Hg:Se molar ratios need to be incorporated in food safety criteria. 相似文献
8.
Wang Y 《Biological trace element research》2009,128(2):184-190
The present research evaluated differential effects of sodium selenite and nano-Se on growth performance, tissue Se distribution,
and glutathione peroxidase (GSH-Px) activity of avian broiler. Broilers were randomly segregated into 12 groups so that three
replicates were available for each of the three treatments (T-1, T-2, and T-3) and control groups. The control groups were
fed basal diets without Se addition. T-1, T-2, and T-3 were fed with diets containing 0.2 mg kg−1 sodium selenite, 0.2 mg kg−1 nano-Se, and 0.5 mg kg−1 nano-Se, respectively. Compared with the control, Se supplementation remarkably improved daily weight gain and survival rate
and decreased feed conversion ratio (P < 0.05). However, no significant difference was observed between T-1, T-2, and T-3. The tissue Se content was significantly
higher (P < 0.05) in Se-supplemented groups than the control, and T-3 showed the highest. Furthermore, higher Se content was observed
in liver, and there was a significant difference (P < 0.05) compared with that in muscle. As for serum and hepatic GSH-Px activities, Se supplementation remarkably improved
GSH-Px activity (P < 0.05), and there was no significant difference (P > 0.05) between treatments (T-1, T-2, and T-3). 相似文献
9.
Selenoprotein W (SelW) is an existing form of selenium (Se). Se influences the levels of SelW in mammals. However, little
is known about the pattern of SelW expression in the gastrointestinal tract tissue of bird. The present paper describes the
effects of different dietary levels of Se on the SelW mRNA expression in the gastrointestinal tract tissue of chicken. The
expression levels of SelW mRNA and the Se contents in the gastrointestinal tract tissues (glandular stomach, gizzard, duodenum,
small intestine, and rectum) were determined on days 15, 25, 35, 45, and 55, respectively. The results showed that the Se
contents and the SelW mRNA expression were significantly higher (p < 0.05) in the high-Se group, and the Se contents and SelW mRNA expression in the low-Se group were significantly lower (p < 0.05) than in the controls. The Se contents were the highest in the duodenum and the lowest in the rectum, while the SelW
mRNA expression was the highest in the gizzard and the lowest in the rectum. In addition, the SelW mRNA levels in the gastrointestinal
tract tissue were found to increase in a time-dependent manner with increasing feeding time. Furthermore, the expression of
the SelW mRNA in the gastrointestinal tract tissues of chickens was found to correlate with the dietary Se concentrations,
but not with the tissue Se contents. 相似文献
10.
To clarify the mineral status in selenium (Se)-deficient rats fed a vitamin-free casein (VFC)-based or torula yeast (TY)-based
diet, 24 weanling male Wistar rats were divided into 4 groups fed diets using VFC or TY as the protein source and containing
Se at sufficient (0.5 μg/g,+Se) or deficient (0.019 μg/g for VFC-based and <0.005 μg/g for TY-based diets,−Se) level for 8 wk. TY supplied a larger amount of extra minerals (Na, K, Ca, Mg, Fe, Mn, Zn, and Cu) except Se than VFC.
Se concentration and glutathione peroxidase activity were significantly lower in TY-fed rats than in VFC-fed rats, as well
as in−Se rats compared to+Se rats. Compared to+Se rats, Fe concentration was higher in liver and muscle of−Se rats fed the VFC-based diet and in plasma, heart, liver, and tibia of−Se rats fed the TY-based diet. Compared to+Se rats, decreases of Mn concentration appeared in plasma, heart, and tibia of VFC-fed−Se rats and in brain, heart, liver and tibia of TY-fed−Se rats. There was also a little imbalance in Ca, Mg, Na, K, and Cu caused by Se deficiency. The results indicated that Se
deficiency induced the mineral imbalance in rats, especially an increase in Fe and decrease in Mn, which was more severe in
TY-fed rats than VFC-fed rats. However, TY cannot be used as a model for both Se and other mineral deficiency because of the
extra minerals except Se found in TY. Instead, VFC can be employed, which contains fewer minerals except Se than TY and also
can produce a severe degree of Se deficiency. 相似文献
11.
To examine whether zinc deficiency would increase the toxicity of dietary aluminum, weanling, male Sprague-Dawley rats were
fed purified diets containing either 2 or 30 mg Zn/kg diet, with or without 500 mg Al/kg diet for 28 d. Individually pair-fed
rats were fed the 30 mg Zn/kg diet with or without added aluminum to control for inanition secondary to zinc deficiency. Rats
fed the 2 μg Zn/kg diet showed evidence of zinc deficiency, including anorexia, growth retardation, and depressed concentrations
of zinc in tibias and livers. Zinc deficiency did not significantly increase the concentrations of aluminum in the tibias,
livers, kidneys, or regions of the brain examined (cerebrum, cerebellum, midbrain, and hippocampus). Inclusion of aluminum
in the diet did not alter aluminum concentrations in the various tissues. Under the conditions of this study, zinc deficiency
did not result in greater sensitivity to dietary aluminum exposure. 相似文献
12.
Five brands of antidiabetic herbal formulations as tablets, Diabetex, Divya Madhu Nashini, Jambrushila, Diabeticin, and Madhumeh Nashini, from different pharmacies were analyzed for six minor (Na, K, Ca, Cl, Mg, and P) and 20 trace (As, Ba, Br, Ce, Co, Cr, Cs,
Cu, Fe, Hg, La, Mn, Rb, Sb, Sc, Se, Sm, Th, V, and Zn) elements by thermal neutron irradiation followed by high-resolution
gamma ray spectrometry. Further Ni, Cd, and Pb were determined by atomic absorption spectrophotometry. Most elements vary
in a narrow range by a factor of 2–4 while a few others vary in a wide range, e.g., Na (0.05–0.67 mg/g), Mn (26.7–250 μg/g),
and V (0.26–2.50 μg/g). All the five brands contain K, Cl, Mg, P, and Ca as minor constituents along with mean trace amounts
of Cr (2.11 ± 0.67 μg/g), Cu (15.7 ± 7.11 μg/g), Fe (459 ± 171 μg/g), Mn (143 ± 23 μg/g), Se (238 ± 112 ng/g), and V (0.99 ± 0.93 μg/g).
Jambrushila is enriched in Na, Ca, Mg, Cl, Fe, Cu, Se, and Zn, essential nutrients responsible for curing diabetes. Dietary intake of
Mn, Fe, and Cu are greater than 10% of the recommended dietary allowance, whereas that for Zn and Se is less than 2%. Mean
contents of toxic elements (As, Cd, Hg, and Pb) were found below permissible limits except in Jambrushila. Cr and Zn were inversely correlated with r = −0.81, whereas Rb and Cs exhibit linear correlation (r = 0.93) in five brands. C, H, N analysis showed C ∼ 55%, H ∼ 12%, and N ∼ 2% with a total of ∼70% organic matter. However,
thermal decomposition studies at 700°C suggest less than 5% nonvolatile metal oxides. Herbal formulations contain minor and
trace elements in bioavailable forms that favorably influence glucose tolerance and possibly increase the body’s ability to
ameliorate development of diabetes. 相似文献
13.
Assessing the effects of low boron diets on embryonic and fetal development in rodents using in vitro and in vivo model systems 总被引:2,自引:0,他引:2
Lanoue L Taubeneck MW Muniz J Hanna LA Strong PL Murray FJ Nielsen FH Hunt CD Keen CL 《Biological trace element research》1998,66(1-3):271-298
To date, boron (B) essentiality has not been conclusively shown in mammals. This article summarizes the results of a series
of in vitro and in vivo experiments designed to investigate the role of B in mammalian reproduction. In the first study, rat
dams were fed either a low (0.04 μg B/g) or an adequate (2.00 μg B/g) B diet for 6 wk before breeding and through pregnancy;
reproductive outcome was monitored on gestation day 20. Although low dietary B significantly lowered maternal blood, liver,
and bone B concentrations, it had no marked effects on fetal growth or development. The goal of the second study was to assess
the effects of B on the in vitro development of rat postimplantation embryos. Day 10 embryos collected from dams fed either
the low or adequate B diets for at least 12 wk were cultured in serum collected from male rats exposed to one of the two dietary
B treatments. Dams fed the low B diet had a significantly reduced number of implantation sites compared to dams fed the B-adequate
diet. However, embryonic growth in vitro was not affected by B treatment. The aim of study 3 was to define the limits of boric
acid (BA) toxicity on mouse preimplantation development in vitro. Two-cell mouse embryos were cultured in media containing
graded levels of BA (from 6 to 10,000 μM). Impaired embryonic differentiation and proliferation were observed only when embryos
were exposed to high levels of BA (>2000 μM), reflecting a very low level of toxicity of BA on early mouse embryonic development.
Study 4 tested the effects of low (0.04 μg B/g) and adequate (2.00 μg B/g) dietary B on the in vitro development of mouse
preimplantation embryos. Two-cell embryos obtained from the dams were cultured in vitro for 72 h. Maternal exposure to the
low B diet for 10, 12, and 16 wk was associated with a reduction in blastocyst formation, a reduction in blastocyst cell number,
and an increased number of degenerates. Collectively, these studies support the concept that B deficiency impairs early embryonic
development in rodents. 相似文献
14.
Brockman JD Raymond LJ Ralston CR Robertson JD Bodkin N Sharp N Ralston NV 《Biological trace element research》2011,144(1-3):812-820
Animal studies indicate that the toxic effects of methylmercury (MeHg) exposures increase when selenium (Se) status is low. Toxicity is directly proportional to Hg/Se molar ratios in critical tissues such as brain and increase dramatically as molar ratios exceed 1:1. In this study, we examined the nail as a biomonitor of Hg/Se molar ratios in kidney, liver, and brain tissues of weanling male Long-Evans rats fed controlled diets containing varying amounts of Se and MeHg. Linear regression analyses indicate that the natural log transform of the Hg/Se ratio in the nails is strongly related to the Hg/Se molar ratio in kidney, liver, and brain (p?0.01 in all cases). The nail appears to be a reliably accurate noninvasive biomonitor of the Hg/Se molar ratio in tissues and should, therefore, be considered for use in human studies. 相似文献
15.
Deficiencies in Cu, Se, and Zn impair one or more biochemical functions, and excess are associated with toxicity. Baseline
studies on the Ghanaian population are scanty. The study was undertaken to determine whether significant rural/urban differences
in the serum levels of Cu, Se, and Zn did exist. Forty males/60 females from rural and 50 males/50 females from urban Ghanaian
communities were sampled. Serum Cu, Se, and Zn were determined using flame atomic absorption spectrometry. Cu level for rural
and urban subjects was 997 ± 333 and 979 ± 290 μg/L, respectively (p = 0.68). However, Cu levels were significantly higher in the rural females (1,063 ± 367 μg/L) than the rural males (898 ± 249 μg/L;
p = 0.0085). Se levels for rural/urban subjects were 97 ± 36 and 87 ± 31 μg/L, respectively (p = 0.03). Zn levels in the rural/urban subjects were 312 ± 218 and 150 ± 102 μg/L, respectively (p = 0.002). Additionally, Zn was significantly higher in rural females (428 ± 204 μg/L) than the urban females (166 ± 103 μg/L;
p = 0.0002). Finally, Zn was significantly higher in rural females (428 ± 204 μg/L) than males (172 ± 116 μg/L; p = 0.0028). In conclusion, Cu, Se, and Zn were higher in the rural group compared to the urban group, and the generally low
Zn levels were confirmed in another cohort follow-up study. 相似文献
16.
The present study was carried out to determine the effects of different sources of selenium (Se; sodium selenite [Na2SeO3] or selenomethionine [Se-Met]) supplementation on egg production, egg quality, levels of malondialdehyde (MDA), and Se in
serum and egg yolk in heat-stressed Japanese quail (Coturnix coturnix japonica). The birds (n = 360; 55 days old) were randomly assigned to 12 treatment groups consisting of six replicates of five birds each in a 2 × 2 × 3
factorial arrangement of treatments (temperatures, selenium sources, selenium levels). Birds were kept in wire cages in a
temperature-controlled room at either 22 (thermoneutral) or 34°C (heat stress) for 8 h/day (09:00–17:00; till the end of study)
and fed a basal (control) diet or the basal diet supplemented with either 0.15 or 0.30 mg of Na2SeO3 or selenomethionine/kg of diet. Heat exposure decreased live weight, feed intake, feed efficiency, egg production, and egg
quality when basal diet was fed (P < 0.0001). A linear increase in feed intake (P = 0.001) and body weight (P = 0.001), egg production (P = 0.001), and improvement in feed efficiency (P = 0.001) and egg quality (P = 0.001) were found in Se-supplemented quail reared under heat stress conditions. Serum, egg white, and egg yolk Se (P ≤ 0.001) concentrations increased linearly, whereas serum, liver, and egg yolk MDA concentrations decreased linearly (P = 0.001) as dietary Na2SeO3 or Se-Met supplementation increased. An interaction between dietary Se sources, temperature, and levels of supplementation
(P ≤ 0.05) for these parameters was detected. Supplementation with Se improved egg production, egg quality, and antioxidant
status of birds, and the effects of Se-Met were relatively greater than Na2SeO3 in heat-stressed quail. Results of the present study suggest that supplementation with Se-Met can be considered to be more
protective than Na2SeO3 by reducing the negative effects of oxidative stress induced by heat stress in quail. 相似文献
17.
Effect of High Dietary Copper on Somatostatin and Growth Hormone-Releasing Hormone Levels in the Hypothalami of Growing Pigs 总被引:1,自引:0,他引:1
Yang W Wang J Liu L Zhu X Wang X Liu Z Wang Z Yang L Liu G 《Biological trace element research》2011,143(2):893-900
This experiment was conducted to examine the effect of dietary copper supplementation on somatostatin (SS) and growth hormone-releasing
hormone (GHRH) mRNA expression levels in the hypothalami of growing pigs. A total of 45 crossbred pigs were randomly assigned
to three groups of 15 pigs each; five replicates of three animals comprised each group. Pigs were allocated to diets that
contained 5 mg/kg copper (control), 125 mg/kg copper sulfate, or 125 mg/kg copper methionine. At the end of the experiment,
five pigs were selected at random from each group and slaughtered, and hypothalami were collected for determination of SS
and GHRH mRNA expression levels. The results showed that the SS expression levels were lower and the GHRH levels were higher
in pigs fed the diets with 125 mg/kg copper methionine (P < 0.05) and 125 mg/kg copper sulfate (P < 0.05), respectively, than in pigs fed the diet with 5 mg/kg copper. Furthermore, the relationship between SS mRNA and GHRH
mRNA abundance had a significantly negative correlation (P < 0.05). The data indicated that high dietary copper could enhance GHRH mRNA expression levels and suppress SS mRNA expression
levels in the hypothalami of pigs. High lever dietary copper (125 mg/kg copper sulfate or 125 mg/kg copper methionine) increased
pigs’ growth performance and feed efficiency but had no significant effect on daily feed intake; 125 mg/kg copper sulfate
or 125 mg/kg copper methionine at the same lever had no difference on growth promoting in pigs. 相似文献
18.
Carol J. Lang Michelle Hansen Eugene Roscioli Jessica Jones Chiara Murgia Margaret Leigh Ackland Peter Zalewski Gary Anderson Richard Ruffin 《Biometals》2011,24(1):23-39
In mouse asthma models, inflammation can be modulated by zinc (Zn). Given that appetite loss, muscle wasting and poor nutrition
are features of chronic obstructive pulmonary disease (COPD) and that poor dietary Zn intake is in itself accompanied by growth
retardation and appetite loss, we hypothesised that dietary Zn limitation would not only worsen airway inflammation but also
exaggerate metabolic effects of cigarette smoke (CS) exposure in mice. Conversely, Zn supplementation would lessen inflammation.
Mice were exposed to CS [2× 2RF, 3×/day; 15 min/cigarette] and fed diets containing 2, 20 or 140 mg/kg Zn ad libitum. Airway
cells were collected by bronchoalveolar lavage (BAL). Plasma Zn was measured by fluorometric assay. Inflammatory, metabolic
and Zn transport markers were measured by real-time RT-PCR. Mice fed low Zn diets had less plasma labile zinc (0–0.18 μM)
than mice fed moderate (0.61–0.98 μM) or high (0.77–1.1 μM) Zn diets (SDs 0.1–0.4, n = 8–10). Smoke exposure increased plasma
and BAL labile Zn (1.5–2.5 fold, P < 0.001), bronchoalveolar macrophages (2.0 fold, P < 0.0001) and MT-1 (1.5 fold), MIP-2 (2.3 fold) and MMP-12 (3.5 fold) mRNA. Zn supplementation reduced alveolar macrophage
numbers by 62 and 52% in sham and smoke-exposed mice, respectively (Zn effect: P = 0.011). Gastrocnemius, soleus and tibialis anterior muscle mass were affected by both smoke and dietary Zn in the order
of 3–7%. The 50–60% reduction in alveolar macrophages in Zn-supplemented mice supports our evolving hypothesis that Zn is
an important anti-inflammatory mediator of airway inflammation. Restoring airway Zn levels through dietary supplementation
may lessen the severity of lung inflammation when Zn intake is low. 相似文献
19.
Zoran Pavlović Ivanka Miletić Živan Jokić Zlatica Pavlovski Zdenka Škrbić Slađana Šobajić 《Biological trace element research》2010,133(2):197-202
A 16-week-long experiment was performed to compare the effect of sodium selenite (SS) and selenium-enriched yeast (SY) supplementation
on eggshell quality and also to evaluate breaking force correlation with other parameters of shell quality originating from
hens fed with selenium supplementation. One hundred Shaver 579 hens (27 weeks old) with similar body size were randomly divided
for five dietary treatments: basal diet without selenium supplementation and basal diets with two levels of selenium supplementation
(0.4 or 0.8 mg/kg) via SS or SY. No adverse effect of Se inclusion in hen's feed, regardless of its source, on shell breaking
force, shell deformation, shape index, shell thickness and shell percentage, were observed throughout the current study (P > 0.05). Moderate correlations were found between breaking force and nondestructive shell deformation for all diets (P < 0.05). There was no significant overall correlation between egg breaking force and shell thickness or/and percentage shell
in the presence of selenium supplemention (P > 0.05). Shape index in all four selenium-supplemented groups was not related to the breaking force (P > 0.05). Selenium supplementation of up to 0.8 mg/kg, regardless of its source, in the diet of laying hens in their first
phase of laying does not adversely affect eggshell quality. 相似文献
20.
This study reports the effects of dietary iron (Fe) deficiency and recovery on bone mineral composition and strength in anemic
rats submitted to a hemoglobin (Hb) repletion assay. Weanling male Wistar rats were fed a low-Fe diet (12 mg/kg) for 15 days
followed by 2 weeks of Fe repletion with diets providing 35 mg Fe/kg as either ferrous sulfate (n = 8) or ferric pyrophosphate (FP; n = 12). At final day of each period (depletion and repletion), Fe-adequate animals were also euthanized. Iron status (blood
Hb, Hb Fe pool, Hb regeneration efficiency), tibia mineral concentrations (Ca, Mg, Fe, Cu, and Zn) and biomechanical properties
were evaluated. Iron-deficient rats had lower tibia Fe and Mg levels and bone strength when compared to controls. Yield load
and resilience were positively related to tibia Mg levels (r = 0.47, P = 0.02 and r = 0.56, P = 0.004, respectively). Iron repletion did not recover tibia Mg concentrations impaired by Fe deficiency. Moreover, bone
elastic properties were negatively affected by FP consumption. In conclusion, bone mineral composition and strength were affected
by Fe deficiency, whereas dietary Fe source influenced tibia Mg and resistance in the period during which rats were recovering
from anemia. 相似文献