Activity of the enzymes of the antioxidative system in cadmium-treated Oxya chinensis (Orthoptera Acridoidae)

One purpose in this research was to determine the toxic effects of Cd on antioxidant enzymes of Oxya chinensis (Orthoptera: Acridoidae). Changes in the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (GPx) were measured in O. chinensis insects injected with Cd²⁺. Fifth-nymphs of O. chinensis insects were injected with Cd²⁺ at different concentrations (0, 0.55 × 10⁻⁴, 1.10 × 10⁻⁴, 1.65 × 10⁻⁴, 2.20 × 10⁻⁴, and 2.75 × 10⁻⁴ g g⁻¹). An increase in SOD activity in O. chinensis was observed at 1.10 × 10⁻⁴ to 2.75 × 10⁻⁴ g g⁻¹ Cd²⁺. The SOD activity was lower at 2.20 × 10⁻⁴and 2.75 × 10⁻⁴ g g⁻¹ than that at 1.10 × 10⁻⁴ and 1.65 × 10⁻⁴ g g⁻¹. It appears that SOD had a positive protective effect at low Cd²⁺ concentrations, and that this effect disappeared at high Cd²⁺ concentrations. CAT activity was accelerated to varying degrees at 1.10 × 10⁻⁴ to 2.75 × 10⁻⁴ g g⁻¹ for males and at 1.10 × 10⁻⁴, 2.20 × 10⁻⁴, and 2.75 × 10⁻⁴g g⁻¹ for females. CAT showed a strong detoxification effect with all treatments. GPx activity decreased with increasing Cd²⁺ concentration with all treatments for males and at 2.20 × 10⁻⁴ and 2.65 × 10⁻⁴g g⁻¹ for females. We showed that GPx activity had a weak detoxification function with all treatments for males and at high Cd²⁺ for females. Thus, CAT had a strong detoxification effect, whereas SOD had a medium and GPx had a weak detoxification effect. Among the three enzymes, CAT played an important role in the damaging mechanisms of reactive oxygen species in O. chinensis insects. Alterations of the antioxidant enzyme level under environmental stresses are suggested as indicators of biotic and abiotic stress.     

一种中华稻蝗成虫抗菌蛋白质的初步分离

目的提取中华稻蝗成虫中的抗菌蛋白质并测定其抗菌活性。方法对中华稻蝗成虫经针刺损伤和菌液浸泡相接合的方法处理,粗提液经沸水浴热变性、凝胶过滤色谱、高效液相色谱分析,初步分离中华稻蝗成虫中的抗菌蛋白质,以金黄色葡萄球菌为指示菌,抑菌圈法检测其抗菌活性。结果经高效液相色谱分析表明中华稻蝗成虫中能产生抗菌蛋白质,其相对分子质量约为3 600。结论首次从直翅目昆虫中华稻蝗中分离到对革兰阳性菌有较强活性的抗菌蛋白质。     

Elevated levels of DNA repair enzymes and antioxidative enzymes by ( )-catechin in murine microglia cells after oxidative stress

(+)-Catechin possesses a broad range of pharmacological properties, including antioxidative effect. However, little is reported on the mechanism by which (+)-catechin protects microglia cells from DNA damage by oxidative stress. In this study, TUNEL assay and DNA electrophorysis indicated that (+)-catechin markedly blocked DNA fragmentation and apoptosis of microglia cells by tBHP exposure. A potent antioxidative effect of (+)-catechin was confirmed by comparison with a putative antioxidant agent, N-acetylcysteine at the lower doses. Furthermore, the increased intracellular ROS by tBHP exposure were scavenged by elevated activities of catalase (CAT) and superoxide dismutase (SOD) after (+)-catechin treament. (+)-Catechin partially inhibited the activation of caspase-3, thereby both cleavage of poly (ADP-ribose) polymerase (PARP) and degradation of inhibitor of caspase-activated DNase (ICAD) were effectively abolished. In addition, the expression of PARP for repair of impaired DNA was significantly increased by (+)-catechin treatment. Taken together, these data suggest that protective effects of (+)-catechin against oxidative DNA damage of microglia cells is exerted by the increased expression of DNA repair enzyme PARP and antioxidant enzyme activities.     

Activity of anandamide (AEA) metabolic enzymes in rat placental bed

Endocannabinoids are endogenous lipid mediators, with anandamide (AEA) being the first member identified. It is now widely accepted that AEA influences early pregnancy events and its levels, which primarily depend on its synthesis by an N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD) and degradation by a fatty acid amide hydrolase (FAAH), must be tightly regulated. Previous studies demonstrated that AEA levels require in situ regulation of these respective metabolic enzymes, and thus, any disturbance in AEA levels may impact maternal remodeling processes occurring during placental development. In this study, the activities of the AEA-metabolic enzymes that result in the establishment of proper local AEA levels during rat gestation were examined. Here, we demonstrate that during placentation NAPE-PLD and FAAH activities change in a temporal manner. Our findings suggest that NAPE-PLD and FAAH create the appropriate AEA levels required for tissue remodeling in the placental bed, a process essential to pregnancy maintenance.     

DNA damage and effects on antioxidative enzymes in zebra fish (Danio rerio) induced by atrazine

The effect of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1, 3, 5-triazine) on the activity of some antioxidative enzymes (superoxide dismutase, SOD; catalase, CAT; and guaiacol peroxidase, POD) and DNA damage induced by atrazine were investigated in zebra fish (Danio rerio). Zebra fish were exposed to four different concentrations of atrazine (0, 2.5, 5, and 10 mg/L) for 7, 14, and 21 days, with three replicates of 10 fishes per treatment. Compared to the controls, the SOD activity in the 2.5 mg/L treatment was markedly stimulated in 21 days, while the SOD activities in the 5 mg/L treatment was stimulated at first and then inhibited. The change of CAT activity at 2.5 mg/L was similar to the SOD activity at 2.5 mg/L. The POD activities in the 2.5, 5, and 10 mg/L treatment were markedly higher on days 14 and 21 compared with the controls. The olive tail moments of single-cell gel electrophoresis (SCGE) of zebra fish enhanced after treatment of different doses on days 7, 14, and 21, and significant differences were found compared to the controls. In conclusion, these findings showed the effect regularity of atrazine to zebra fish, and also provide the basis for the future research of adverse effects induced by atrazine in aquatic ecosystems.     

Effect of zinc on hepatic lipid peroxidation and antioxidative enzymes in ethanol-fed rats

A 3-ml aliquot of 30% ethanol was fed daily to normal as well as zinc-treated (227 mg l(-1)) rats for periods of 2, 4 and 8 weeks. A highly significant increase in the levels of hepatic lipid peroxidation was observed in ethanol-fed rats after 4 and 8 weeks of treatment. On the other hand, the levels of lipid peroxidation came down significantly following ethanol feeding to zinc-treated rats. The activities of glutathione peroxidase (GPx), catalase and superoxide dismutase (SOD) in liver were elevated significantly after ethanol administration to rats for durations of 2, 4 and 8 weeks. Interestingly, zinc treatment to rats given ethanol was able to bring down the elevated levels of SOD, catalase and GPx to within normal limits, However, zinc administration alone did not cause any significant alteration in the activities of these antioxidative enzymes.     

Elevated levels of DNA repair enzymes and antioxidative enzymes by (+)-catechin in murine microglia cells after oxidative stress

(+)-Catechin possesses a broad range of pharmacological properties, including antioxidative effect. However, little is reported on the mechanism by which (+)-catechin protects microglia cells from DNA damage by oxidative stress. In this study, TUNEL assay and DNA electrophorysis indicated that (+)-catechin markedly blocked DNA fragmentation and apoptosis of microglia cells by tBHP exposure. A potent antioxidative effect of (+)-catechin was confirmed by comparison with a putative antioxidant agent, N-acetylcysteine at the lower doses. Furthermore, the increased intracellular ROS by tBHP exposure were scavenged by elevated activities of catalase (CAT) and superoxide dismutase (SOD) after (+)-catechin treatment. (+)-Catechin partially inhibited the activation of caspase-3, thereby both cleavage of poly (ADP-ribose) polymerase (PARP) and degradation of inhibitor of caspase-activated DNase (ICAD) were effectively abolished. In addition, the expression of PARP for repair of impaired DNA was significantly increased by (+)-catechin treatment. Taken together, these data suggest that protective effects of (+)-catechin against oxidative DNA damage of microglia cells is exerted by the increased expression of DNA repair enzyme PARP and antioxidant enzyme activities.     

Elevated levels of DNA repair enzymes and antioxidative enzymes by (+)-catechin in murine microglia cells after oxidative stress

(+)-Catechin possesses a broad range of pharmacological properties, including antioxidative effect. However, little is reported on the mechanism by which (+)-catechin protects microglia cells from DNA damage by oxidative stress. In this study, TUNEL assay and DNA electrophorysis indicated that (+)-catechin markedly blocked DNA fragmentation and apoptosis of microglia cells by tBHP exposure. A potent antioxidative effect of (+)-catechin was confirmed by comparison with a putative antioxidant agent, N-acetylcysteine at the lower doses. Furthermore, the increased intracellular ROS by tBHP exposure were scavenged by elevated activities of catalase (CAT) and superoxide dismutase (SOD) after (+)-catechin treament. (+)-Catechin partially inhibited the activation of caspase-3, thereby both cleavage of poly (ADP-ribose) polymerase (PARP) and degradation of inhibitor of caspase-activated DNase (ICAD) were effectively abolished. In addition, the expression of PARP for repair of impaired DNA was significantly increased by (+)-catechin treatment. Taken together, these data suggest that protective effects of (+)-catechin against oxidative DNA damage of microglia cells is exerted by the increased expression of DNA repair enzyme PARP and antioxidant enzyme activities.     

Low in situ expression of antioxidative enzymes in rat cerebellar granular cells susceptible to methylmercury

Methylmercury (MeHg), an environmental neurotoxicant, induces site-specific toxicity in the brain. Although oxidative stress has been demonstrated with MeHg toxicity, the site-specific toxicity is not completely understood. Among the cerebellar neurons, cerebellar granule cells (CGCs) appear vulnerable to MeHg, whereas Purkinje cells and molecular layer neurons are resistant. Here, we use a MeHg-intoxicated rat model to investigate these cerebellar neurons for the different causes of susceptibility to MeHg. Rats were exposed to 20 ppm MeHg for 4 weeks and subsequently exhibited neuropathological changes in the cerebellum that were similar to those observed in humans. We first isolated the three cerebellar neuron types using a microdissection system and then performed real-time PCR analyses for antioxidative enzymes. We observed that expression of manganese-superoxide dismutase (Mn-SOD), glutathione peroxidase 1 (GPx1), and thioredoxin reductase 1 (TRxR1) was significantly higher in Purkinje cells and molecular layer neurons than in CGCs. Finally, we performed immunohistochemical analyses on the cerebellum. Immunohistochemistry showed increased expression of Mn-SOD, GPx1, and TRxR1 in Purkinje cells and molecular layer neurons, which was coincident with the mRNA expression patterns. Considering Mn-SOD, GPx1, and TRxR1 are critical for protecting cells against MeHg intoxication, the results indicate that low expression of these antioxidative enzymes increases CGCs vulnerability to MeHg toxicity.     

吸烟所致宫内发育迟缓孕鼠肝脏药物代谢酶及抗氧化酶活性的变化

目的:研究和探讨吸烟所致宫内发育迟缓(IUGR)大鼠母体肝脏药物代谢酶活性和抗氧化功能的改变及其所带来的毒理学和药理学意义。方法:妊娠天数明确的Wistar大鼠16只,分为对照组和吸烟组。采用吸烟法建立大鼠IUGR模型,孕21d剖腹取胎,测量胎鼠生长发育指标(体重、身长、尾长)和胎盘重。差速离心法制备孕鼠肝亚细胞组分,测定多种药物代谢酶和抗氧化酶活性。结果:IUGR大鼠胎仔平均体重、身长、尾长、胎盘重都明显低于对照组,分别为对照组的87.7%、94.5%、95.3%和83.0%(P<0.01)。母体肝脏微粒体细胞色素P450(CYP)1A1活性升高,为对照组的137.9%(P<0.05);而CYP3A活性降低,为对照组的73.3%(P<0.05),谷胱甘肽S转移酶(GST)活性也降低,为对照组的86.5%(P<0.05)。母体肝脏胞浆超氧化物歧化酶(SOD)和过氧化氢酶(Cat)活性降低(P<0.05);谷胱甘肽过氧化物酶(GSHPx)活性升高,为对照组的1.11倍(P<0.05)。结论:孕期吸烟可致IUGR大鼠母体肝脏部分药物代谢酶活性和抗氧化系统功能改变,这些改变可能是导致IUGR发生的原因之一,同时吸烟可能改变孕期用药的疗效,增加药物毒性。     

Interaction in vitro of nicotinamide and diethylnicotinamid (cordiamine) with enzymes of the liver microsomal hydoxylating system in the rat

Addition of nicotinamide and diethylnicotinamide (cordiamine) to rat liver microsomes leads to the formation of an enzyme-substrate Type II complex with cytochrome P-450. Diethylnicotinamide exceeded nicotinamide approximately 2-fold as regards the degree of the affinity to the enzyme. The ability of nicotinamide and diethylnicotinamide to interact with cytochrome P-450 underlies their antagonism with respect to in-vitro metabolism of the substrates of both Type I (amidopyrine) and Type II (aniline) as well as with respect to the competition with CO for the common center of binding on the enzyme.     

Effect of astaxanthin on the hepatotoxicity, lipid peroxidation and antioxidative enzymes in the liver of CCl4-treated rats

Astaxanthin is one of many carotenoids present in marine animals, vegetables and fruits. Since carotenoids are known to have antioxidant properties, we tested to determine if astaxanthin could have protective effects in the CCl4-treated rat liver by activating the antioxidant system. Astaxanthin blocked the increase of glutamate-oxalacetate transaminase (GOT) and glutamate-pyruvate transaminase (GTP) activity and thiobarbituric acid reactive substances (TBARS) in response to carbon tetrachloride (CCl4), while causing an increase in glutathione (GSH) levels and superoxide dismutase (SOD) activities in the CCl4-treated rat liver. These results suggest that astaxanthin protects liver damage induced by CCl4 by inhibiting lipid peroxidation and stimulating the cellular antioxidant system.     

硒化紫球藻胞外多糖毒性及抗氧化活性的研究

目的 研究硒化紫球藻胞外多糖的毒性及抗氧化活性.方法 采用在培养液中添加亚硒酸,制备硒化紫球藻胞外多糖(Se-PSP);在体外培养条件下,测量其对细胞代谢活力的抑制率;建立小鼠动物模型,测量各项抗氧化功能指标.结果 Se-PSP对LO-2的半抑制浓度为80ìg·mL-1;Se-PSP(80,160 mg·kg-1)对小鼠不仅无毒性,而且还有促进其生长、抗氧化等保健功能.结论 Se-PSP在80,160 mg·kg-1低浓度范围内,可以发挥硒多糖的抗氧化等活性.