Effects of chronic benzene poisoning on DNA and antioxidase of mice

Dong CHANG; Hong SUI; Hongzhi PAN; Lixin NA

ABSTRACT

BACKGROUND:

As an important industrial solvent,benzene can cause DNA damage,chromosome aberrence,formation of DNA adducts and gene mutation.

OBJECTIVE:

To explore the effects of benzene on DNA and the mechanism,as well as the changes of antioxidase system it caused.

DESIGN:

Randomized case control study.

SETTING:

The Department of Clinical Laboratory of First Affiliated Hospital and Public Health College of Harbin Medical University.

PARTICIPANTS:

The experiment was completed in the Animal Centre in Public Health College,Harbin Medical University.Twenty-four healthy male mice of Kunming species weighed between 18 g to 22 g were chosen.The mice were provided by Experimental Animal Centre of Second Affiliated Hospital,Harbin Medical University.

INTERVENTIONS:

The mice were divided into control group,low dose benzene group and high dose benzene group.Inhaling benzene smoke method was used 4 hours per day to cause benzene poisoning to mice except those of the control group.The mice were executed two months later to separate marrow cells and peripheral lymphocytes and remove liver,spleen and brain to make homogenate. MAIN OUTCOME

MEASURES:

Single cell gel electrophoresis (SCGE) was used to assay the DNA damages of marrow cells and peripheral lymphocytes.Meanwhile,the contents of superoxide dismulase(SOD),glutathione peroxidase(GSH-Px) and malondialdehyde(MDA) in liver,spleen and brain tissues were also detected.

RESULTS:

The comet percentage of marrow cells and peripheral lymphocytes in two benzene poisoning groups were(83.56± 10.28),(92.54± 15.93)% ,and(41.27± 6.03)% ,(65.79± 11.62)% respectively which were much higher than those in control group[(4.13± 0.52)% ,(2.21± 0.31)% ](P< 0.01) and represented dose-response relationship.The SOD activity of liver homogenate and GSH-Px activity of high dose and low dose groups were (11 573.31± 1 938.72),(12 574.68± 1 938.72) nkat/g and (309.40± 82.85),(375.41± 55.18) nkat/g respectively which were much lower than those in control group [(16 668.67± 3 137.96),(588.62± 110.52) nkat/g] (P< 0.05).However, there was no significant difference between different dose groups. The GSH-Px activity in spleen homogenate in two experimental groups was(421.75± 124.02) and(523.10± 45.18) nkat/g respectively which was much lower than that of control group [(618.42± 57.01) nkat/g](P< 0.05) and there was significant difference between two groups (P< 0.05).In the brain homogenate of both benzene groups,the GSH-Px activity was(87.35± 19.84) and(95.02± 14.00) nkat/g respectively which was much lower than that of control group[(118.36± 7.67) nkat/g] (P< 0.05) and without difference between two groups.The MDA content in brain homogenate of high dose group was(3.99± 1.15) μ mol/mg which was much higher than that of control group [(2.58± 0.53) μ mol/g] (P< 0.05).

CONCLUSION:

Chronic benzene poisoning can cause DNA impairment of marrow cells and peripheral lymphocytes and reduce the activity of antioxidase.