Ozturk I Cetin, Batcioglu Kadir
Biochemistry Department, Medical School, Inonu University, 44069 Malatya, Turkey.
J Biochem Mol Toxicol. 2002;16(5):260-2. doi: 10.1002/jbt.10041.
7,12-Dimethylbenz[a]anthracene (7,12-DMBA) is a member of the polycyclic aromatic hydrocarbons with a severe carcinogenic effect. In this study, nitrate levels and ADA (Adenosine deaminase) activity in the liver homogenates of mice were measured and the effect of free radicals induced by 7,12-DMBA on inducible nitric oxide synthase (iNOS) and ADA activity were investigated. Antioxidant effects of melatonin were also compared. Three groups of mice were included in the study. The first served as control, the second was treated only with 7,12-DMBA and the third was treated with 7,12-DMBA + melatonin. Spectrophotometric methods were used at all measurements. Data were analyzed using Kruskal-Wallis Variance Analysis Test and Mann-Whitney U Test that were applied to the groups. The nitrate concentrations of mouse liver were as follows: 4.98 +/- 0.63 micro mol/L in the control group (n = 10), 8.23 +/- 1.58 micro mol/L (higher than control group, p < 0.05) in the 7,12-DMBA-treated group (n = 10), and 6.43 +/- 0.57 micro mol/L (lower than 7,12-DMBA-treated group, p < 0.05) in the 7,12-DMBA + melatonin-treated group (n = 10). Liver ADA activities were measured to be 4.14 +/- 0.674 U/L in the control group, 6.25 +/- 1.261 U/L (higher than control group, p < 0.05) in the 7,12-DMBA-treated group, and 4.93 +/- 0.916 U/L (lower than 7,12-DMBA-treated group, p < 0.05) in the 7,12-DMBA+melatonin-treated group. Differences between free nitrite levels were no significantly. Results demonstrated that nitrate levels and ADA activities were increased by means of free radicals induced by 7,12-DMBA. Melatonin inhibited the 7,12-DMBA induced increase that was observed in the activities of ADA enzyme and nitrate levels. It is concluded that determination of ADA activity and nitrate levels can be useful in the assessment of liver damage caused by toxic chemicals.
7,12-二甲基苯并[a]蒽（7,12-DMBA）是一种具有严重致癌作用的多环芳烃。在本研究中，测定了小鼠肝脏匀浆中的硝酸盐水平和腺苷脱氨酶（ADA）活性，并研究了7,12-DMBA诱导的自由基对诱导型一氧化氮合酶（iNOS）和ADA活性的影响。还比较了褪黑素的抗氧化作用。该研究纳入了三组小鼠。第一组作为对照组，第二组仅用7,12-DMBA处理，第三组用7,12-DMBA +褪黑素处理。所有测量均采用分光光度法。使用Kruskal-Wallis方差分析检验和Mann-Whitney U检验对各组数据进行分析。小鼠肝脏的硝酸盐浓度如下：对照组（n = 10）为4.98±0.63微摩尔/升，7,12-DMBA处理组（n = 10）为8.23±1.58微摩尔/升（高于对照组，p < 0.05），7,12-DMBA +褪黑素处理组（n = 10）为6.43±0.57微摩尔/升（低于7,12-DMBA处理组，p < 0.05）。测得肝脏ADA活性在对照组为4.14±0.674 U/L，7,12-DMBA处理组为6.25±1.261 U/L（高于对照组，p < 0.05），7,12-DMBA +褪黑素处理组为4.93±0.916 U/L（低于7,12-DMBA处理组，p < 0.05）。游离亚硝酸盐水平之间的差异无统计学意义。结果表明，7,12-DMBA诱导的自由基使硝酸盐水平和ADA活性升高。褪黑素抑制了7,12-DMBA诱导的ADA酶活性和硝酸盐水平的升高。结论是，测定ADA活性和硝酸盐水平有助于评估有毒化学物质对肝脏造成的损害。
