Comparative study on the effects of micro- and nano-sized zinc oxide supplementation on zinc-deficient mice.

BACKGROUND: Zinc (Zn) is an essential cofactor for physiological homeostasis in the body. Zn oxide (ZnO), an inorganic compound that supplies Zn, exists in various sizes, and its bioavailability may vary depending on the size in vivo. However, comparative studies on the nutritional effects of micro-sized ZnO (M-ZnO) and nano-sized ZnO (N-ZnO) supplementation on Zn deficiency (ZnD) animal models have not been reported. OBJECTIVES: This study investigated the nutritional bioavailability of N-ZnO and M-ZnO particles in dietary-induced ZnD mice. METHODS: Animals were divided into six experimental groups: normal group, ZnD control group, and four ZnO treatment groups (Nano-Low, Nano-High, Micro-Low, and Micro-High). After ZnD induction, N-ZnO or M-ZnO was administered orally every day for 4 weeks. RESULTS: ZnD-associated clinical signs almost disappeared 7 days after N-ZnO or M-ZnO administration. Serum Zn concentrations were higher in the Nano-High group than in the ZnD and M-ZnO groups on day 7 of ZnO treatment. In the liver and testis, Nano-Low and Nano-High groups showed significantly higher Zn concentrations than the other groups after 14-day treatment. ZnO supplementation increased Mt-1 mRNA expression in the liver and testis and Mt-2 mRNA expression in the liver. Based on hematoxylin-and-eosin staining results, N-ZnO supplementation alleviated histological damage induced by ZnD in the testis and liver. CONCLUSIONS: This study suggested that N-ZnO can be utilized faster than M-ZnO for nutritional restoration at the early stage of ZnD condition and presented Mt-1 as an indicator of Zn status in the serum, liver, and testis.

Epigallocatechin-3-gallate suppresses hemin-aggravated colon carcinogenesis through Nrf2-inhibited mitochondrial reactive oxygen species accumulation.

BACKGROUND: Previous studies have presented evidence to support the significant association between red meat intake and colon cancer, suggesting that heme iron plays a key role in colon carcinogenesis. Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, exhibits anti-oxidative and anti-cancer effects. However, the effect of EGCG on red meat-associated colon carcinogenesis is not well understood. OBJECTIVES: We aimed to investigate the regulatory effects of hemin and EGCG on colon carcinogenesis and the underlying mechanism of action. METHODS: Hemin and EGCG were treated in Caco2 cells to perform the water-soluble tetrazolium salt-1 assay, lactate dehydrogenase release assay, reactive oxygen species (ROS) detection assay, real-time quantitative polymerase chain reaction and western blot. We investigated the regulatory effects of hemin and EGCG on an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colon carcinogenesis mouse model. RESULTS: In Caco2 cells, hemin increased cell proliferation and the expression of cell cycle regulatory proteins, and ROS levels. EGCG suppressed hemin-induced cell proliferation and cell cycle regulatory protein expression as well as mitochondrial ROS accumulation. Hemin increased nuclear factor erythroid-2-related factor 2 (Nrf2) expression, but decreased Keap1 expression. EGCG enhanced hemin-induced Nrf2 and antioxidant gene expression. Nrf2 inhibitor reversed EGCG reduced cell proliferation and cell cycle regulatory protein expression. In AOM/DSS mice, hemin treatment induced hyperplastic changes in colon tissues, inhibited by EGCG supplementation. EGCG reduced the hemin-induced numbers of total aberrant crypts and malondialdehyde concentration in the AOM/DSS model. CONCLUSIONS: We demonstrated that EGCG reduced hemin-induced proliferation and colon carcinogenesis through Nrf2-inhibited mitochondrial ROS accumulation.

Enhanced Protective Effects of Combined Treatment with ß-Carotene and Curcumin against Hyperthermic Spermatogenic Disorders in Mice.

Scrotal hyperthermia leads to oxidative stress and apoptosis in spermatogenic cells, which subsequently causes male infertility. In this study, we examined the effects of ß-carotene and/or curcumin on heat-stress- (HS-) induced testicular injuries in mice. ICR male mice (8 weeks old) were consecutively treated with ß-carotene (10 mg/kg) and/or curcumin (20 mg/kg) orally once a day for 14 days and then subjected to single exposure with scrotal HS at 43°C for 15 min on day 7. HS induced a significant reduction in testicular weight, appearance of multinucleated giant cells, and desquamation of germ cells in destructive seminiferous tubules, as well as degenerative Leydig cells. Moreover, HS reduced the superoxide dismutase (SOD) activity and mRNA levels of mitochondrial SOD, phospholipid hydroperoxide glutathione peroxidase, B-cell lymphoma-extra-large, and 3ß-hydroxysteroid dehydrogenase, with increases in lipid peroxidation levels and mRNA levels of BCL2-associated X protein and caspase-3 relative to those of the control group. However, these changes were significantly recovered by combined treatment with ß-carotene and curcumin after HS. These findings indicate that the combined treatment with ß-carotene and curcumin might be a valuable protective agent to ameliorate hyperthermic spermatogenic disorders via its potent antioxidative, antiapoptotic, and androgen synthetic effects.

Shear bond strength of porcelain to a new millable alloy and a conventional castable alloy.

STATEMENT OF PROBLEM: A recently introduced presintered cobalt-chromium (Co-Cr) alloy for metal ceramic restorations can be efficiently processed with computer-aided design/computer-aided manufacturing (CAD/CAM) techniques. However, little or no reliable study data are available regarding the bonding ability of porcelain to milled Co-Cr alloys. PURPOSE: The purpose of this study was to evaluate the shear bond strength of veneering porcelain to the presintered Co-Cr alloy and to a conventional castable alloy. MATERIAL AND METHODS: Ninety-six cylindrical cores (6.8 mm in diameter, 9 mm in height) were made of millable alloy (Ceramill Sintron) and castable alloy (4-all) by means of CAD/CAM or casting, 48 cores for each alloy. Four types of veneering porcelain were fired or pressed to the cores; these specimens had dimensions of 4×4×3 mm. After firing, the specimens were put in resin molds, fixed in a universal testing machine, and subjected to a shear force test. Loading was applied to each specimen through the attached crosshead at a constant drive speed of 0.5 mm/min until fracture occurred. Shear bond strengths (MPa) were calculated by dividing the maximum failure force over the cross-sectional area of each specimen. Failure patterns of the specimens were also investigated and characterized as adhesive, cohesive, or mixed. One-way ANOVA and the Duncan post hoc test were used to analyze statistically significant differences between groups (α=.05). RESULTS: The means of the shear bond strengths of (millable) Ceramill Sintron were similar to or higher than those of (castable) 4-all cores. The shear bond strength was significantly lower for Press-To-Metal veneer than for the other fired veneers in the test (P<.001). The pattern of failure in most specimens was mixed, except for Press-To-Metal veneer, where cohesive failure occurred. CONCLUSIONS: The bonding ability of the traditional castable alloy was similar to that of the presintered millable Co-Cr alloy.

Toxicity of colloidal silica nanoparticles administered orally for 90 days in rats.

This study was undertaken to investigate the potential toxicity and establish the no observed adverse effect level (NOAEL) and target organ(s) of negatively charged colloidal silica particles of different sizes, ie, SiO2 (EN20(-)) (20 nm) or SiO2 (EN100(-)) 2(100 nm), administered by gavage in Sprague-Dawley rats. After verification of the physicochemical properties of the SiO2 particles to be tested, a preliminary dose range-finding study and 90-day repeated dose study were conducted according to the Organisation for Economic Cooperation and Development test guideline. Based on the results of the 14-day dose range-finding study, a high dose was determined to be 2,000 mg/kg, and middle and low doses were set at 1,000 and 500 mg/kg, respectively. In the 90-day toxicity study, there were no animal deaths in relation to administration of SiO2 particles of either size. In addition, no treatment-related clinical changes or histopathological findings were observed in any of the experimental groups. Moreover, no difference in toxic effects from chronic exposure to SiO2 (EN20(-))(20 nm) or SiO2 (EN100(-)) (100 nm) was observed. The results of this study indicate that the NOAEL for SiO2 (EN20(-)) and SiO2 (EN100(-)) would most likely be 2,000 mg/kg, and no target organ was identified in rats of either sex.

Antiteratogenic Effects of ß-Carotene in Cultured Mouse Embryos Exposed to Nicotine.

After maternal intake, nicotine crosses the placental barrier and causes severe embryonic disorders and fetal death. In this study, we investigated whether ß -carotene has a beneficial effect against nicotine-induced teratogenesis in mouse embryos (embryonic day 8.5) cultured for 48 h in a whole embryo culture system. Embryos exposed to nicotine (1 mM) exhibited severe morphological anomalies and apoptotic cell death, as well as increased levels of TNF- α , IL-1 ß , and caspase 3 mRNAs, and lipid peroxidation. The levels of cytoplasmic superoxide dismutase (SOD), mitochondrial manganese-dependent SOD, cytosolic glutathione peroxidase (GPx), phospholipid hydroperoxide GPx, hypoxia inducible factor 1 α , and Bcl-x L mRNAs decreased, and SOD activity was reduced compared to the control group. However, when ß -carotene (1 × 10(-7) or 5 × 10(-7) µM) was present in cultures of embryos exposed to nicotine, these parameters improved significantly. These findings indicate that ß -carotene effectively protects against nicotine-induced teratogenesis in mouse embryos through its antioxidative, antiapoptotic, and anti-inflammatory activities.

Inhibitory effect of ethanol extract of Magnolia officinalis on memory impairment and amyloidogenesis in a transgenic mouse model of Alzheimer's disease via regulating ß-secretase activity.

Alzheimer's disease (AD) is the most common form of dementia and is characterized by deposition of amyloid beta (Aß) in the brain. The components of the herb Magnolia officinalis are known to have antiinflammatory, antioxidative and neuroprotective activities. In this study we investigated the effects of ethanol extract of M. officinalis on memory dysfunction and amyloidogenesis in a transgenic mouse model of AD. Oral pretreatment of ethanol extract of M. officinalis (10 mg/kg in 0.05% ethanol) into drinking water for 3 months inhibited memory impairment and Aß deposition in the brain of Tg2576 mice. Ethanol extract of M. officinalis also decreased activity of ß-secretase, cleaving Aß from amyloid precursor protein (APP), and expression of ß-site APP cleaving enzyme 1 (BACE1), APP and its product, C99. Our results showed that ethanol extract of M. officinalis effectively prevented memory impairment via down-regulating ß-secretase activity.

Suppressive effect of zinc on the formation of colonic preneoplastic lesions in the mouse fed high levels of dietary iron.

We investigated the effect of zinc on the formation of colonic aberrant crypt foci induced by azoxymethane (AOM) followed by dextran sodium sulfate (DSS) in mice with high iron diet (HFe; 450 ppm iron). Sixweek old ICR mice were fed on high iron diets with combination of three different levels of zinc in diets, low-zinc (LZn; 0.01 ppm), medium-zinc (MZn; 0.1 ppm), and high-zinc (HZn; 1 ppm) for 12 weeks. Animals were received weekly intraperitoneal injections of AOM (10 mg/kg B.W. in saline) for 3 weeks followed by 2% DSS (molecular weight 36,000~50,000) in the drinking water for a week. To confirm the iron storage in the body, the hepatic iron concentration has been determine chemically and compared with histological assessment visualized by Prussian blue reaction. Aberrant crypt (AC) and aberrant crypt foci (ACF) were analyzed in the colonic mucosa of mouse fed high dietary iron. Superoxide dismutase (SOD) activity and thiobarbituric acid-reactive substances (TBARS) level were also investigated. Apoptosis in the preneoplastic lesion was determined by terminal deoxynucleotidyl transferase-mediated dUTP nickend labeling (TUNEL). In addition, immunohistochemistry of ß-catenin was also performed on the mucous membrane of colon. The number of large ACF (≥ 4 AC/ACF), which possess greater tumorigenic potential, was significantly lower in MZn and HZn groups compared with LZn group. Cytosolic SOD activity in the liver was significantly higher in HZn group compared with LZn group. Hepatic MDA level was decreased significantly in HZn group compared with MZn and LZn groups. Apoptotic index was significantly higher in HZn group. Taken together, these findings indicate that dietary zinc might exert a protective effect against colonic preneoplastic lesion induced by AOM/DSS in ICR mice with high iron status, and suggest that dietary supplement of zinc might play a role in suppressing colon carcinogenesis in mice.

Effects of selenium on colon carcinogenesis induced by azoxymethane and dextran sodium sulfate in mouse model with high-iron diet.

Selenium (Se) is known to prevent several cancers while the relationship between high iron and the risk of colorectal cancer is controversial. To investigate the effects of Se in colon carcinogenesis, we subjected three different levels of Se and high-iron diet to a mouse model of colon cancer in which animals were treated with three azoxymethane (AOM) injections followed by dextran sodium sulfate (DSS) administration. There were five experimental groups including vehicle group [normal-Fe (NFe, 45 ppm)+medium-Se (MSe, 0.1 ppm)], positive control group (AOM/DSS+NFe+MSe), AOM/DSS+high-Fe (HFe, 450 ppm)+low-Se (LSe, 0.02 ppm), AOM/DSS+HFe+MSe, and AOM/DSS+HFe+high-Se (HSe, 0.5 ppm). The animals were fed on the three different Se diets for 24 weeks. The incidence of colon tumor in the high-Se diet group (AOM/DSS+HFe+HSe) showed 19.4% lower than positive control group, 5.9% lower than AOM/DSS+HFe+MSe diet group, and 11.1% lower than AOM/DSS+HFe+LSe group. The tumor multiplicity was significantly higher in the low-Se diet group (AOM/DSS+HFe+LSe) compare to all other AOM/DSS treated groups. In the high-Se diet group, the activity of hepatic GPx was comparable to that of positive control group, and significantly higher than those of low-Se or medium-Se diet groups. Expression level of hepatic GPx-1 showed similar results. Hepatic malondialdehyde (MDA) level (indicator of oxidative stress) in the low-Se diet group showed the highest compared to the other groups, and it was significantly higher than positive control group. In the high-Se diet group the level of MDA in the liver was significantly lower than all other AOM/DSS treated groups. High-Se diet group showed significantly lower proliferative index than low-Se and medium-Se groups. The apoptotic indices in low-Se group and medium-Se group were significantly lower than positive control group. However, apoptotic index of high-Se diet group was significantly higher than all other AOM/DSS treated groups. These findings suggest that dietary Se supplement may have protective effect against colon cancer by decreasing proliferation, increasing apoptosis of tumor cells, and reducing oxidative stress in mice with high iron diet.

Inhibitory effect of ethanol extract of Magnolia officinalis and 4-O-methylhonokiol on memory impairment and neuronal toxicity induced by beta-amyloid.

The components of the herb Magnolia officinalis have exhibited antioxidant and neuroprotective activities. In this study, we investigated effects of ethanol extract of M.officinalis and its major component 4-O-methylhonokiol on memory dysfunction and neuronal cell damages caused by A beta. Oral pretreatment of ethanol extract of M. officinalis (2.5, 5 and 10mg/kg) and 4-O-methylhonokiol (1mg/kg) into drinking water for 5 weeks suppressed the intraventricular treatment of A beta(1-42) (0.5 microg/mouse, i.c.v.)-induced memory impairments. In addition, 4-O-methylhonokiol prevented the A beta(1-42)-induced apoptotic cell death as well as beta-secretase expression. 4-O-methylhonokiol also inhibited H(2)O(2) and A beta(1-42)-induced neurotoxicity in cultured neurons as well as PC12 cells by prevention of the reactive oxygen species generation. 4-O-methylhonokiol also directly inhibited beta-secretase activity and A beta fibrilization in vitro. Thus, ethanol extract of M. officinalis may be useful for prevention of the development or progression of AD, and 4-O-methylhonokiol may be a major active component.

Protective effect of the ethanol extract of Magnolia officinalis and 4-O-methylhonokiol on scopolamine-induced memory impairment and the inhibition of acetylcholinesterase activity.

Magnolol, honokiol, and obovatol are well-known bioactive constituents of the bark of Magnolia officinalis and have been used as traditional Chinese medicines for the treatment of neurosis, anxiety, and stroke. We recently isolated novel active compound (named 4-O-methylhonokiol) from the ethanol extract of Magnolia officinalis. The present study aimed to test two different doses of ethanol extracts of Magnolia officinalis (5 and 10 mg/kg/mouse, p.o., 1 week) and 4-O-methylhonokiol (0.75 and 1.5 mg/kg/mouse, p.o., 1 week) administered for 7 days on memory impairment induced by scopolamine (1 mg/kg body weight i.p.) in mice. Memory and learning were evaluated using the Morris water maze and the step-down avoidance test. Both the ethanol extract of Magnolia officinalis and 4-O-methylhonokiol prevented memory impairment induced by scopolamine in a dose-dependent manner. The ethanol extract of Magnolia officinalis and 4-O-methylhonokiol also dose-dependently attenuated the scopolamine-induced increase of acetylcholinesterase (AChE) activity in the cortex and hippocampus of mice, and inhibited AChE activity in vitro with IC(50) (12 nM). This study, therefore, suggests that the ethanol extract of Magnolia officinalis and its major ingredient, 4-O-methylhonokiol, may be useful for the prevention of the development or progression of AD.

Black ginseng inhibits ethanol-induced teratogenesis in cultured mouse embryos through its effects on antioxidant activity.

Fetal alcohol syndrome is caused by excessive ethanol consumption during pregnancy. We investigated the effect of black ginseng (red ginseng that is subjected to 9 cycles of 95-100 degrees C for 2-3h) on ethanol-induced teratogenesis using an in vitro whole embryo culture system. Postimplantational mouse embryos at embryonic day 8.5 were exposed to ethanol (1 microl/ml) in the presence or absence of black ginseng (1, 10, and 100 microg/ml) for 2 days, and then morphological scoring and real-time PCR analysis were carried out. In ethanol-treated embryos, the total morphological score and individual scores for flexion, heart, fore-, mid-, and hindbrains, otic, optic, and olfactory systems, branchial bars, maxillary and mandibular processes, caudal neural tube, and somites were significantly lower than the control group (p<0.05). Treatment with black ginseng improved most of the morphological scores significantly as compared to ethanol-treated embryos (p<0.05). The mRNA levels of the antioxidant enzymes cytosolic glutathione peroxidase (GPx), phospholipid hydroperoxide GPx, and selenoprotein P were significantly decreased in ethanol-treated embryos, but co-treatment with black ginseng restored the mRNA levels to those of control embryos. These results indicate that black ginseng has a protective effect on ethanol-induced teratogenesis through the augmentation of antioxidative activity in embryos.

Effects of exposure to genistein and estradiol on reproductive development in immature male mice weaned from dams adapted to a soy-based commercial diet.

Genistein, a soybean-originated isoflavone, is widely consumed by humans for putative beneficial health effects but its estrogenic activity may adversely affect the development of male reproductive system. Twenty one-day-old ICR mice weaned from dams fed with a soybean-based diet throughout gestation and lactation were exposed by gavage to genistein (2.5 mg/kg b.w./day) or 17beta-estradiol (7.5 microg/kg b.w./day) for five weeks. Corn oil was used as a negative control. The animals were fed with a casein-based AIN-76A diet throughout the experimental periods. There were no significant differences in body and organ weights of mice among experimental groups. No significant differences in sperm counts and sperm motile characteristics were found between control and genistein groups. Treatment of 17beta-estradiol caused a significant decrease in prostate weight and epididymal sperm counts compared to the control (p<0.05). The levels of phospholipid hydroxide glutathione peroxidase in the testis and prostate of mice exposed to genistein or 17beta-estradiol were significantly higher than that of the control mice (p<0.05). 17beta-estradiol treatment caused degeneration and apoptosis of germ cells in the testis, depletion and degeneration in the epididymal epithelium, and hyperplasia of mucosal fold region in the prostate of mice. Genistein treatment did not cause any lesion in the testis, epididymis, and prostate. These results suggest that dietary uptake of genistein during juvenile period may not affect male reproductive development and functions.

Modulating effects of Korean ginseng saponins on ovarian function in immature rats.

The modulating effects of Korean ginseng saponins on ovarian functions were investigated in immature rats superovulated with pregnant mare serum gonadotropin (PMSG). A single dose of 1 mg (0.1 ml/head) of Korean ginseng total saponin (GTS), Korean ginseng protopanaxatriol saponin (GPT), Korean ginseng protopanaxadiol saponin (GPD), or ginsenoside-Rb1 (Gin-Rb1) was intravenously injected via jugular vein catheter three times at 1 h (early follicular phase), 25 h (middle follicular phase), and 50 h (late follicular phase) after 30 IU PMSG administration. GPD and Gin-Rb1 significantly suppressed excessive ovulatory response caused by PMSG (p<0.05). All Korean ginseng saponins significantly improved oocyte quality by decreasing the proportion of abnormal oocytes (p<0.05). Gin-Rb1 significantly decreased preovulatory serum levels of androgens and 17beta-estradiol, while GPD increased preovulatory serum progesterone level (p<0.05). GPD significantly the increased postovulatory serum progesterone level (p<0.05). These results provide strong evidence that Korean ginseng saponins have a curative effect on ovarian dysfunction caused by excessive stimulation with PMSG.