溴酸盐的遗传毒性

目的 探讨臭氧消毒饮用水副产物溴酸盐的遗传毒性。方法 采用Ames试验、UDS试验和微核试验，从基因水平、DNA水平和染色体水平对臭氧消毒副产物溴酸盐的遗传毒性进行研究。结果与阴性对照组相比，副产物溴酸盐不能使组氨酸缺陷型鼠伤寒沙门菌回复突变增加，但可使大鼠肝细胞程序外DNA合成增加和小鼠骨髓嗜多染红细胞微核形成率增加。结论 臭氧消毒副产物溴酸盐可能具有DNA及染色体水平的遗传毒性。     

Mammalian cell cytotoxicity and genotoxicity analysis of drinking water disinfection by-products

Cytotoxicity and genotoxicity assays were used to analyze drinking water disinfection by-products (DBPs) in Chinese hamster ovary (CHO) AS52 cells. The DBPs were chosen because they are common in drinking water, resulting from conventional disinfection using chlorination and chloramination. Data were also available to compare these results with cytotoxicity and mutagenicity studies in Salmonella typhimurium. The rank order in decreasing chronic cytotoxicity measured in a microplate-based assay was bromoacetic acid (BA) > 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX) > dibromoacetic acid (DBA) > chloroacetic acid (CA) > KBrO(3) > tribromoacetic acid (TBA) > EMS (ethylmethanesulfonate, positive control) > dichloroacetic acid (DCA) > trichloroacetic acid (TCA). The induction of DNA strand breaks by these agents was measured by alkaline single-cell gel electrophoresis (SCGE, comet assay) and the rank order in decreasing genotoxicity was BA > MX > CA > DBA > TBA > EMS > KBrO(3), while DCA and TCA were refractory. BA was more cytotoxic (31x) and genotoxic (14x) than MX in CHO cells. BA was over 400x more genotoxic than potassium bromate. The brominated haloacetic acids (HAAs) were more cytotoxic and genotoxic than their chlorinated analogs. The HAAs expressed a statistically significant inverse relationship in CHO cell cytotoxicity and genotoxicity as a function of increased numbers of halogen atoms per molecule. A quantitative comparison was conducted with results from a previous study with cytotoxicity and mutagenicity in S. typhimurium. There was no correlation between chronic CHO cell and bacterial cell cytotoxicity. DBP-induced CHO cell cytotoxicity was not related to mutagenic potency in S. typhimurium. Cytotoxicity in CHO cells was statistically significant and highly correlated to CHO cell genotoxicity. Finally, we determined that the DBP genotoxic potency in CHO cells and the mutagenic potency in S. typhimurium were not related. This suggests that toxicity data in S. typhimurium did not quantitatively predict the toxic effects of DBPs in mammalian cell systems. The microplate CHO cell cytotoxicity and genotoxicity assays were well suited for the analysis of DBPs, especially when the quantity of test material is limited.     

Effects of dibutyl phthalate in male rabbits following in utero, adolescent, or postpubertal exposure.

We evaluated sequelae in male rabbits following exposure to dibutyl phthalate (DBP) at a dose level known to adversely affect testicular function in rodents without causing systemic toxicity. Because rabbits have a relatively long phase of reproductive development simulating better than rodents the reproductive development of humans, and because the use of rabbits facilitates multiple evaluations of mating ability and seminal quality, we used this animal model. Rabbits were exposed to 0 or 400 mg DBP/kg/day in utero (gestation days [GD] 15-29) or during adolescence (postnatal weeks [PNW] 4-12), and male offspring were examined at 6, 12, and 25 weeks of age. Another group was exposed after puberty (for 12 weeks) and examined at the conclusion of exposure. The most pronounced reproductive effects were in male rabbits exposed in utero. Male offspring in this group exhibited reduction in numbers of ejaculated sperm (down 43%; p < 0.01), in weights of testes (at 12 weeks, down 23%; p < 0.05) and in accessory sex glands (at 12 and 25 weeks, down 36%; p < 0.01 and down 27%; p < 0.05, respectively). Serum testosterone levels were down (at 6 weeks, 32%; p < 0.05); a slight increase in histological alterations of the testis (p < 0.05) and a doubling in the percentage (from 16 to 30%, p < 0.01) of abnormal sperm; and 1/17 males manifesting hypospadias, hypoplastic prostate, and cryptorchid testes with carcinoma in situ-like cells. In the DBP group exposed during adolescence, basal serum testosterone levels were reduced at 6 weeks (p < 0.01) while at 12 weeks, testosterone production in vivo failed to respond normally to a GnRH challenge (p < 0.01). In addition, weight of accessory sex glands was reduced at 12 weeks but not at 25 weeks after a recovery period; there was a slight increase in the percentage of abnormal sperm in the ejaculate; and 1/11 males was unilaterally cryptorchid. In both of these DBP-treated groups, daily sperm production, epididymal sperm counts, mating ability, and weights of body and nonreproductive organs were unaffected. Thus, DBP induces lesions in the reproductive system of the rabbit, with the intrauterine period being the most sensitive stage of life.     

复方真武冲剂对家兔实验性心力衰竭的血流动力学影响

目的观察中药复方真武冲剂(CZWG)对家兔实验性心力衰竭的血流动力学影响.方法结扎左冠状动脉前降支(LAD)方法复制家兔心力衰竭的实验模型.将家兔随机分为六组,采用左心室和股动脉插管术测定血流动力学指标 dp/dtmax、-dp/dtmax、LVEDP、SBP、DBP、MAP,针状电极记录二导联心电图.结果与假手术组比较,A组家免血流动力学发生显著异常;与A组相比,B组家兔 dp/dtmax、-dp/dtmax、LVEDP升高,LVEDP、HR降低,C组家兔有不同程度的改善,其中B组明显优于E组.结论CZWG能改善家兔实验性心力衰竭的血流动力学的异常,且CZWG中剂量作用明显.     

Pyruvate remediation of cell stress and genotoxicity induced by haloacetic acid drinking water disinfection by‐products

Monohaloacetic acids (monoHAAs) are a major class of drinking water disinfection by‐products (DBPs) and are cytotoxic, genotoxic, mutagenic, and teratogenic. We propose a model of toxic action based on monoHAA‐mediated inhibition of glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) as a target cytosolic enzyme. This model predicts that GAPDH inhibition by the monoHAAs will lead to a severe reduction of cellular ATP levels and repress the generation of pyruvate. A loss of pyruvate will lead to mitochondrial stress and genomic DNA damage. We found a concentration‐dependent reduction of ATP in Chinese hamster ovary cells after monoHAA treatment. ATP reduction per pmol monoHAA followed the pattern of iodoacetic acid (IAA) > bromoacetic acid (BAA) >> chloroacetic acid (CAA), which is the pattern of potency observed with many toxicological endpoints. Exogenous supplementation with pyruvate enhanced ATP levels and attenuated monoHAA‐induced genomic DNA damage as measured with single cell gel electrophoresis. These data were highly correlated with the S_N2 alkylating potentials of the monoHAAs and with the induction of toxicity. The results from this study strongly support the hypothesis that GAPDH inhibition and the possible subsequent generation of reactive oxygen species is linked with the cytotoxicity, genotoxicity, teratogenicity, and neurotoxicity of these DBPs. Environ. Mol. Mutagen. 54:629–637, 2013. © 2013 Wiley Periodicals, Inc.     

Skin permeation and metabolism of di(2-ethylhexyl) phthalate (DEHP)

Phthalates are suspected to be endocrine disruptors. Di(2-ethylhexyl) phthalate (DEHP) is assumed to have low dermal absorption; however, previous in vitro skin permeation studies have shown large permeation differences. Our aims were to determine DEHP permeation parameters and assess extent of skin DEHP metabolism among workers highly exposed to these lipophilic, low volatile substances.     

The potential of DBP gels containing intervertebral disc cells for annulus fibrosus supplementation:in vivo

Demineralized bone particle (DBP), which is widely used as a biomaterial in the field of tissue engineering, contains various bioactive molecules, such as cytokines. For this reason, in this study we investigated the effects of injectable DBP gels on cell proliferation, inflammation and maintenance of the shape of DBP gels as a scaffold able to substitute for intervertebral discs (IVDs) in vivo. DBP gels were fabricated with different percentages (5% and 10%) of DBP powder and 3% acetic acid, including 0.02% pepsin. DBP gels with 1 × 10⁶ annulus fibrosus (AF) cells were implanted into the dorsal subcutaneous region of BALB/C‐nu mice for 1, 2 and 3 weeks. Cell proliferation was measured by MTT assay. The effect of DBP gels on the inflammatory response was analysed by measuring the amount of tumour necrosis factor‐alpha (TNFα) released. Also, histological methods were carried out to analyse the response of DBP gels in vivo. This study demonstrated that injectable DBP gels are able to provide physical scaffolds for growing IVD cells in vivo. Copyright © 2013 John Wiley & Sons, Ltd.