Genotoxic evaluation of titanium dioxide nanoparticles in vivo and in vitro

With the extensive application of titanium dioxide (TiO₂) nanoparticles (NPs) in food industry, there is a rising debate concerning the possible risk associated with exposure to TiO₂ NPs. The purpose of this study is to evaluate the genotoxicity of TiO₂ NPs using in vivo and in vitro test systems. In vivo study, the adult male Sprague-Dawley rats were exposed to anatase TiO₂ NPs (75 ± 15 nm) through intragastric administration at 0, 10, 50 and 200 mg/kg body weight every day for 30 days. The γ-H₂AX assay showed TiO₂ NPs could induce DNA double strand breaks in bone marrow cells after oral administration. However, the micronucleus test revealed that the oral-exposed TiO₂ NPs did not cause damage to chromosomes or mitotic apparatus observably in rat bone marrow cells. In vitro study, Chinese hamster lung fibroblasts (V79 cells) were exposed to TiO₂ NPs at the dose of 0, 5, 10, 20, 50 and 100 μg/mL. Significant decreases in cell viability were detected in all the treated groups after 24 h and 48 h exposure. Significant DNA damage was only observed at the concentration of 100 μg/mL after 24 h treatment using the comet assay. The obvious gene mutation was observed at the concentration of 20 and 100 μg/mL after 2 h treatment using hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene mutation assay. This study presented a comprehensive genotoxic evaluation of TiO₂ NPs, and TiO₂ NPs were shown to be genotoxic both in vivo and in vitro tests. The gene mutation and DNA strand breaks seem to be more sensitive genetic endpoints for the detection of TiO₂ NPs induced genotoxic effects.     

Long-term effects of total-body irradiation on the kidney of Rhesus monkeys

PURPOSE: To investigate the long-term effects of total-body irradiation (TBI) on kidneys in non-human primates. METHODS AND MATERIALS: The kidneys of Rhesus monkeys were histologically examined at 6-8 years after TBI with low single doses of 4.5-8.5Gy or two fractions of 5.4Gy. The kidneys of age-matched non-irradiated monkeys served as controls. Irradiation was performed on adult monkeys aged about 3 years; 6-8 years later animals were sacrificed and the kidneys removed and processed for histology. A semi-quantitative scoring system was used to evaluate overall histological damage. Glomerular changes were also morphometrically analysed according to previously published criteria. In selected dose groups (pro)thrombotic and inflammatory changes were investigated by immunostaining cryosections with antibodies against von Willebrand factor (vWF), leukocytes and macrophages. RESULTS: Histological changes were generally mild and only seen in kidneys irradiated with doses higher than 7 Gy. Glomerular changes were characterized by increased mesangial matrix and capillary dilatation. Tubulo-interstitial changes included hypercellularity, fibrosis and mild tubular atrophy. The mean glomerular area expressing vWF protein in the irradiated kidneys was not different from that in the age-matched controls. Numbers of infiltrating leukocytes were not significantly different between irradiated kidneys and controls. However, slightly increased numbers of macrophages were present in the renal cortex after irradiation. CONCLUSIONS: Renal damage after TBI of Rhesus monkeys with single doses of 4.5-8.5 Gy or two fractions of 5.4 Gy was mild, even after follow-up times of 6-8 years.     

中哈边境口岸臀突客蚤检出立克次氏体核酸

目的了解中哈边境地区臀突客蚤(Xenopsylla minax)中立克次氏体携带情况。方法收集阿拉山口口岸臀突客蚤样本,PCR扩增立克次体17 kDa基因片段,PCR产物测序并BLAST比对,利用Mega 6.0构建分子遗传进化树。结果42.86%(3/7)的臀突客蚤携带立克次体,17 kDa基因遗传进化树显示与Candidatus Rickettsia senegalensis和Rickettsia bellii同源性最高。结论中哈边境口岸地区臀突客蚤携带立克次体核酸。     

Houttuynia cordata Thunb. Volatile Oil Exhibited Anti‐inflammatory Effects In Vivo and Inhibited Nitric Oxide and Tumor Necrosis Factor‐α Production in LPS‐stimulated Mouse Peritoneal Macrophages In Vitro

Houttuynia cordata Thunb. (HC) is a medicinal herb that generally used in traditional Chinese medicine for treating allergic inflammation. The present study investigated the inhibitory effect of the volatile oil from HC Thunb. on animal models of inflammation and the production of inflammatory mediators in vivo and in vitro. In vivo, xylene‐induced mouse ear edema, formaldehyde‐induced paw edema and carrageenan‐induced mice paw edema were significantly decreased by HC volatile oil. HC volatile oil showed pronounced inhibition of prostaglandin (PG) E₂ and malondialdehyde production in the edematous exudates. In vitro exposure of mouse resident peritoneal macrophages to 1, 10, 100 and 1000 µg/mL of HC volatile oil significantly suppressed lipopolysaccharide (LPS)‐stimulated production of NO and tumor necrosis factor‐α (TNF‐α) in a dose‐dependent manner. Exposure to HC volatile oil had no effect on cell viability and systemic toxicity. Furthermore, HC volatile oil inhibited the production of NO and TNF‐α by down‐regulating LPS‐stimulated iNOS and TNF‐α mRNA expression. Western blot analysis showed that HC volatile oil attenuated LPS‐stimulated synthesis of iNOS and TNF‐α protein in the macrophages, in parallel. These findings add a novel aspect to the biological profile of HC and clarify its anti‐inflammatory mechanism. Copyright © 2012 John Wiley & Sons, Ltd.     

Bone healing in osteoporotic female rats following intra-alveolar grafting of bioactive glass

We have investigated the effect of ovariectomy combined with a low Ca diet on bone healing following the implantation of bioactive glass into extraction sockets, in rats. Ovariectomized rats received a low Ca diet from the day of surgery until sacrifice while sham-operated animals were fed a standard laboratory chow. Two weeks after surgery the upper incisors were extracted and the alveolar sockets in both groups were partially filled with a particulate bioglass (PerioGlas^®). The animals were killed 1, 2, 3 and 9 weeks after tooth extraction and the relative volume fraction of the healing components (bone trabeculae, connective tissue and coagulum remnants) was estimated in histological paraffin sections by a histometric differential point-counting method. The bioglass particles persisted inside the socket for all the experimental periods and, as bone repair proceeded, they were progressively enclosed in newly formed bone trabeculae which in some cases established a close contact with their surface. The volume fraction of neoformed bone trabeculae relative to the volume fraction of connective tissue and coagulum remnants was greater in the sockets of ovariectomized animals implanted with bioglass than in those of the overiectomized non-implanted groups.     

β‐Eudesmol Induces JNK‐Dependent Apoptosis through the Mitochondrial Pathway in HL60 Cells

β‐eudesmol, a natural sesquiterpenol present in a variety of Chinese herbs, is known to inhibit the proliferation of human tumor cells. However, the molecular mechanisms of the effect of β‐eudesmol on human tumor cells are unknown. In the present study, we report the cytotoxic effect of β‐eudesmol on the human leukemia HL60 cells and its molecular mechanisms. The cytotoxic effect of β‐eudesmol on HL60 cells was associated with apoptosis, which was characterized by the presence of DNA fragmentation. β‐eudesmol‐induced apoptosis was accompanied by cleavage of caspase‐3, caspase‐9, and poly (ADP‐ribose) polymerase; downregulation of Bcl‐2 expression; release of cytochrome c from mitochondria; and decrease in mitochondrial membrane potential (MMP). Activation of c‐Jun N‐terminal kinases (JNK) mitogen‐activated protein kinases was observed in β‐eudesmol‐treated HL60 cells, and the inhibitor of JNK blocked the β‐eudesmol‐induced apoptosis, downregulation of Bcl‐2, and the loss of MMP. These data suggest that β‐eudesmol induces apoptosis in HL60 cells via the mitochondrial apoptotic pathway, which is controlled through JNK signaling. Copyright © 2012 John Wiley & Sons, Ltd.     

The effects of NOS1 gene on asthma and total IgE levels in Taiwanese children,and the interactions with environmental factors

Wang T‐N, Tseng H‐I, Kao C‐C, Chu Y‐T, Chen W‐Y, Wu P‐F, Lee C‐H, Ko Y‐C. The effects of NOS1 gene on asthma and total IgE levels in Taiwanese children, and the interactions with environmental factors.
Pediatr Allergy Immunol 2010: 21: 1064–1071.
© 2010 John Wiley & Sons A/S Asthma is a complex disorder, which is known to be affected by interactions between genetic and environmental factors. The aim of this study was to investigate the three microsatellite polymorphisms of GT repeats in intron 2, AAT repeats in intron 20, and CA repeats in exon 29 of the NOS1 gene in 155 asthmatic children and 301 control children, and the interaction with environmental factors in southern Taiwan. Total serum IgE, phadiatop test and genetic polymorphisms were measured. The genotype frequency of 14/14‐AAT repeats of the NOS1 gene was significantly higher in the asthmatic group (p = 0.01). Total IgE concentrations were higher in asthmatic children (p = 0.015) carrying the NOS1 14/14‐AAT genotype than in subjects with other polymorphisms. The gene and environmental interaction effects were 3.83‐fold, 6.86‐fold, and 8.04‐fold (all corrected p‐values <0.001) between subjects carrying at least one NOS1 14‐AAT allele and exposure to cockroaches, high levels of total IgE, and positive response against the phadiatop test in asthmatic children. The findings of this study provide strong evidence that NOS1 gene with 14‐AAT tandem repeats has a significant effect in asthmatic children. Environmental factors and atopic status will enhance the asthmatic risk for children who carry NOS1 susceptible allele.     

人精子DNA从头甲基化转移酶及甲基CpG结合蛋白的mRNA表达分析

目的 通过体外分离成熟的精子,利用实时荧光定量PCR(qRealTime-PCR)检测其是否表达DNA从头甲基化转移酶(DNMT1/3a/3b)及甲基CpG结合蛋白(MeCP2),为精子中甲基化表观修饰研究提供依据.方法 体外采集健康男性志愿者的精液标本,利用精子上游收集法获得具有活性的成熟精子.通过SYBR Green/PI双染色法,利用流式细胞术(FCM)检测精子样本的质膜完好性及其活性.抽提精子的总RNA,逆转录PCR获得cDNA,利用qRealTime-PCR鉴定精子甲基化转移酶及甲基CpG结合蛋白的mRNA表达情况.结果 SYBR Green/PI双染色和流式细胞仪检测发现,利用上游收集法可以收集SYBR Green /PI-的精子占总精子数的(94.513±1.120)%,表明该方法可以收集到质膜完好且活性强的精子.qRealTime-PCR结果显示,此样本精子中DNA从头甲基化转移酶的表达比较明显,而甲基CpG结合蛋白的表达量相当低.其中DNMT1的mRNA表达量较高(0.272±0.045,P＜0.05),DNMT3a和DNMT3b的表达水平比较弱[(4.930±0.01)E-006,(6.500±1.7)E-005,P＜0.05],而MeCP2几乎不表达[(2.12±0.91)E-006,p＜0.05].结论 利用qRealTime-PCR可以比较快速方便的检测出此次精子样本中DNA从头甲基化转移酶和甲基CpG结合蛋白的mRNA表达水平.     

The role of interferon-gamma in murine pneumococcal pneumonia.

To determine the role of interferon (IFN)-gamma in pneumonia, IFN-gamma receptor-deficient (IFN-gamma R(-/-)) and 129/Sv (wild-type [wt]) mice were inoculated intranasally with Streptococcus pneumoniae. Although mortality did not differ between the groups 48 h after inoculation, IFN-gamma R(-/-) mice had significantly fewer pneumococci in their lungs than the wt mice. Similarly, IFN-gamma(-/-) mice had fewer colony-forming units in lungs than wt mice. The relatively increased resistance of IFN-gamma R(-/-) mice was not related to favorable effects on defense mechanisms known to contribute to antibacterial immunity-that is, the neutrophilic influx was reduced and the cytokine and nitric oxide levels were similar or lower in IFN-gamma R(-/-) mice. In contrast, mice treated with anti-IFN-gamma did not demonstrate a consistently altered bacterial outgrowth, compared with mice treated with a control antibody. These data suggest that endogenous IFN-gamma, despite its protective role in defense against intracellular pathogens, does not serve a protective role during pneumococcal pneumonia.