Tissue zinc levels in precancerous tissue in the gastrointestinal tract of azoxymethane (AOM)-treated rats

Alterations in tissue zinc levels have been documented in patients with gastrointestinal tract malignancies and more frequently, in those with colonic cancer. However, the precise role of tissue zinc in carcinogenesis is not well elucidated. This study, using a well-established colon cancer model in rats, was designed to investigate the relationship of tissue zinc to the carcinogenic process. The aim was to examine tissue zinc levels in the preneoplastic tissues and to study the changes that occur during transition of mucosa from normal to preneoplastic state. Six-week old rats were given a single dose subcutaneous injection of azoxymethane (AOM) (30mg/kg body weight) and sacrificed after 1, 2, 5, and 9 months of the treatment. Plasma zinc levels showed a significant decrease (p<0.05) at 9 months compared with controls. Tissue zinc levels showed a significant decrease in the large intestine at 1 and 2 months (p<0.05) and at 5 and 9 months (p<0.01), in the small intestine at 2, 5, and 9 months (p<0.05), and in the stomach at 5 and 9 months (p<0.05). The maximum percent decrease (45%) in tissue zinc was observed in the large intestine at 9 months. Tissue copper zinc super oxide dismutase (CuZnSOD) activity was assessed in the body of the stomach, small intestine, and large intestine and compared with the control group. There was a significant fall in CuZnSOD levels in the small intestine at 9 months (p<0.05) and in the large intestine at 5 and 9 months (p<0.01). Two of these six rats showed histological evidence of precancerous lesions in the mucosa of the colon. This study suggests that the decrease in plasma zinc, tissue zinc and activity of CuZnSOD is associated with development of preneoplastic lesions in the colonic mucosa.     

Antioxidant enzyme activities are not broadly correlated with longevity in 14 vertebrate endotherm species

The free radical theory of ageing posits that accrual of oxidative damage underlies the increased cellular, tissue and organ dysfunction and failure associated with advanced age. In support of this theory, cellular resistance to oxidative stress is highly correlated with life span, suggesting that prevention or repair of oxidative damage might indeed be essential for longevity. To test the hypothesis that the prevention of oxidative damage underlies longevity, we measured the activities of the five major intracellular antioxidant enzymes in brain, heart and liver tissue of 14 mammalian and avian species with maximum life spans (MLSPs) ranging from 3 years to over 100 years. Our data set included Snell dwarf mice in which life span is increased by ∼50% compared to their normal littermates. We found that CuZn superoxide dismutase, the major cytosolic superoxide dismutase, showed no correlation with MLSP in any of the three organs. Similarly, neither glutathione peroxidase nor glutathione reductase activities correlated with MLSP. MnSOD, the sole mitochondrial superoxide dismutase in mammals and birds, was positively correlated with MLSP only for brain tissue. This same trend was observed for catalase. For all correlational data, effects of body mass and phylogenetic relatedness were removed using residual analysis and Felsenstein’s phylogenetically independent contrasts. Our results are not consistent with a causal role for intracellular antioxidant enzymes in longevity, similar to recent reports from studies utilising genetic modifications of mice (Pérez et al., Biochim Biophys Acta 1790:1005–1014, 2009). However, our results indicate a specific augmentation of reactive oxygen species neutralising activities in brain associated with longevity.     

甜菜碱对载脂蛋白E~(-/-)小鼠动脉粥样硬化发生过程中铜锌超氧化物岐化酶基因甲基化及表达的影响

目的 检测栽脂蛋白E-/-小鼠动脉粥样硬化发生过程中肝脏铜锌超氧化物岐化酶基因启动子区CpG岛甲基化及其表达状态,探讨甜菜碱对动脉粥样硬化的作用及其可能的机刺.方法 将正常的C57BL/6J小鼠作为正常对照组,同品系载脂蛋白E-/-小鼠分为模型组、1%、2%和4%甜菜碱组.用油红O染色法检测小鼠主动脉窦脂质斑块面积,应用甲基化特异性聚合酶链反应检测肝脏钢锌超氧化物岐化酶基因甲基化,荧光定量逆转录聚合酶链反应检测铜锌超氧化物岐化酶mRNA表达,免疫组织化学检测其蛋白表达.结果 饲养至14周,2%和4%甜菜碱组小鼠主动脉窦脂质斑块面积明显少于模型组(P<0.05);各组铜锌超氧化物岐化酶基因CpG岛甲基化状态差异无显著性(P>0.05);各时间段正常对照组铜锌超氧化物岐化酶mBNA表达均高于模型组,7周时1%甜菜碱组mRNA表达高于2%和4%甜菜碱组,14周时1%甜菜碱组mRNA表达高于模型组和2%甜菜碱组;各时间段正常对照组铜锌超氧化物歧化酶蛋白表迭均高于模型组、1%、2%和4%甜菜碱组(P<0.05),但模型组、1%、2%和4%甜菜碱组间无显著性差异.结论 铜锌超氧化物岐化酶基因可能没有参与动脉粥样硬化过程中DNA甲基化的异常改变,补充甜菜碱可以增加肝脏铜锌超氧化物岐化酶mBNA表达,改善载脂蛋白E>-/-小鼠的脂质沉积,减少主动脉窦粥样斑块面积.     

Unsymmetrical DMH – An isomer of 1,2 DMH – Is it potent to induce gastrointestinal carcinoma in rats?

Very few animal studies have used 1,1-dimethyl hydrazine (unsymmetrical dimethyl hydrazine – UDMH) as a carcinogen. This study was designed to investigate the carcinogenicity of UDMH in the gastrointestinal tract in a rat model. We wanted to observe if there were any changes in tissue zinc levels and tissue copper zinc superoxide dismutase (CuZnSOD) enzyme activity during the carcinogenic process, and to compare these values with those of control rats in the medium- and long-term. Six-week-old Wistar rats were given a subcutaneous injection of UDMH (30 mg/kg body wt) twice a week for 20 weeks, and sacrificed after 5 and 9 months of treatment. Tissue zinc levels showed a significant decrease (p<0.05) in the large intestine at 9 months, whereas in the stomach and small intestine there were no significant changes at 5 and 9 months. Tissue CuZnSOD enzyme activity in the stomach, small intestine and large intestine showed no significant decrease at 5 and 9 months as compared to controls. Histologically, the large intestine was normal at 9 months.

This study suggests that UDMH administered at the above dosage was not carcinogenic in this model.     

In vitro effect of sodium fluoride on antioxidative enzymes and apoptosis during murine odontogenesis

J Oral Pathol Med (2010) 39 : 709–714 Excessive fluoride ingestion has been identified as a risk factor for fluorosis and oxidative stress. The oxidative stress results from the loss of equilibrium between oxidative and antioxidative mechanisms that can produce kinase activation, mitochondrial disturbance and DNA fragmentation, resulting in apoptosis. Actually many people are exposed to no‐adverted fluoride consumption in acute or chronic way. The aim of this study was to determine the effect of sodium fluoride on first molar germ in relation to its effect on antioxidative enzymes immunoexpression and apoptosis. Thirty first molar germs from 1‐day‐old Balb/c mice were cultured for 24 h with sodium fluoride (0 mM, 1 mM and 5 mM). Immunoexpression determination of CuZnSod, MnSod, catalase, Bax, Bid, caspase 8, caspase 9, caspase 3 and TUNEL assay were perfomed. Cellular disorganization in ameloblast and odontoblast‐papilla zones was observed. CuZnSod and MnSod immunoexpression decrease in experimental groups. Caspase 8, caspase 3, Bax, Bid increase expression and more TUNEL positive cells in both experimental groups than control, suggest that apoptosis induced by fluoride is related to oxidative stress due to reduction of the enzymatic antioxidant.     

食管癌及癌前增生人群血清CuZnSOD的定量研究

用酶联免疫吸附试验法(ELISA)对食管癌及癌前各期增生患者进行了血清CuZnSOD的定量测定,以探讨上述人群血清CuZnSOD活力下降的可能机制。结果显示,随食管上皮细胞病变的进展,机体血清CuZnSOD含量显著升高,呈现与CuZnSOD活力相反的变化趋势。提示食管癌患者CuZnSOD活力的下降,并非酶合成量的不足,而可能系某些因素导致无活性CuZnSOD存在的结果。     

A strategy for the ubiquitous overexpression of human catalase and CuZn superoxide dismutase genes in transgenic mice

In the present study, we generated transgenic mice that overexpress catalase or CuZn superoxide dismutase (CuZnSOD) in all tissues using large genomic DNA fragments. An 80 kb human genomic DNA, containing the 33 kb human CAT gene as well as the 41 kb of 5' and the 6 kb of 3' flanking regions, was obtained by screening a human P1 library and was used to produce transgenic mice Tg(CAT). Transgenic mice Tg(SOD1) were produced by a similar strategy using a 64 kb human genomic DNA containing the 10 kb human SOD1 gene and the 27 kb of both 5' and 3' flanking regions. Catalase mRNA levels were 2-6- fold higher and catalase activity levels were 2-4- fold higher in the various tissues of the hemizygous Tg(CAT) mice compared with wild type mice. The mRNA levels for CuZnSOD were 2-12- fold higher and the CuZnSOD activity levels were 2-5- fold higher in the hemizygous Tg(SOD1) mice compared with wild type mice. In summary, our study demonstrates that a strategy of using large genomic DNA containing either the entire human CAT or SOD1 gene with large flanking regions gives ubiquitous increased expression of CuZnSOD and catalase. In addition, the expression of catalase closely reflects the tissue specific pattern found in the endogenous gene. These transgenic mice will be useful in studying the role of oxidative stress/damage in aging and age-related pathologies.     

表皮肿瘤组织超氧化物歧化酶的表达及意义

目的 :探讨铜锌超氧化物歧化酶(CuZnSOD)和锰超氧化物歧化酶 (MnSOD)在表皮肿瘤中的表达及作用。方法 :通过半定量逆转录聚合酶链式反应 (RT PCR)和蛋白免疫印记 (WesternBlot)方法 ,研究了 2 6例基底细胞癌(Basalcellcarcinoma)、2 3例鳞状细胞癌 (Squa mascellcarcinoma)、18例日光性角化 (ActinicKeratosis)以及 8例曝光部正常皮肤、8例非曝光部正常皮肤中CuZnSOD和MnSOD的mRNA和蛋白表达水平。结果 :正常皮肤曝光部和非曝光部 2种SOD的mRNA和蛋白表达无差别 ;表皮肿瘤中CuZnSODmRNA表达与正常皮肤一致 ,MnSODmRNA表达升高 ;表皮肿瘤中 2种SOD蛋白的表达较正常皮肤低。结论 :表皮肿瘤中SOD的mRNA与蛋白表达水平存在差异 ,低蛋白表达可能与表皮肿瘤发生有关。     

Wen-pi-tang-Hab-Wu-ling-san reduces ureteral obstructive renal fibrosis by the reduction of oxidative stress,inflammation, and TGF-β/Smad2/3 signaling

Kidney fibrosis results in chronic renal disease. The current treatment of chronic renal diseases is limited to angiotensin converting enzyme inhibitors and angiotensin receptor blockers. Recently, we found that Wen-pi-tang-Hab-Wu-ling-san (WHW) extract, which has been used to treat renal diseases in herbal medicine for a long time, plays anti-fibrogenic. Here, we investigated the role of WHW in the kidney fibrosis induced by unilateral ureteral obstruction (UUO) in mice. C57BL/6 male mice were subjected to UUO on day 0 and then administered with either WHW (2, 10, or 50 mg/kg of body weight) or vehicle orally from 1 day after UUO to finish the experiment. WHW-administration significantly mitigated the UUO-induced kidney fibrotic changes including tubular atrophy and dilatation, collagen accumulation, expansion of interstitial space and leukocyte infiltration. WHW prevented the increases of oxidative stress by the prevention of UUO-induced decreases of catalase, copper–zinc superoxide dismutase (CuZnSOD) and manganese superoxide dismutase (MnSOD), resulting in reduced production of oxidative stress. Furthermore, WHW reduced transforming growth factor-β (TGF-β) expression and phosphorylation of Smad2/3 stimulated by UUO. In conclusion, WHW prevented kidney fibrosis following UUO by the inhibition of inflammation, oxidative stress and TGF-β/Smad2/3 signaling pathway.