Sister Chromatid Exchange and Chromosomal Aberration Frequencies in Peripheral Blood Lymphocytes of Workers Occupationally Exposed to Benzene and the Effects of Antioxidants Thereon
Khadiga Salah Ibrahim1, Saida Hammad2, Safaa El-Serougy1, Nevin Sharaf1, 
and Hend Rashad1
1 Department of Environmental and Occupational Medicine, National Research Centre, Cairo, Egypt
2 Department of Human Cytogenetics, National Research Centre, Cairo, Egypt
Corresponding author: Khadiga Salah Ibrahim
	
    Environmental and Occupational Medicine Department
	
    National Research Centre, Cairo, Egypt
	
    Fax number: 00202-3370931
	
    E-mail: khadigasalah@yahoo.com
 CEJOEM 2006, Vol.12. No.4.: 243–256
Key words:
Chromosomal aberrations, sister chromatid exchange, benzene, antioxidant
Abstract:
In the present study, chromosomal aberration (CA) and sister chromatid exchange (SCE) frequencies induced in 
lymphocytes of workers occupationally exposed to benzene were evaluated by a standard method of metaphase analysis. 
Twenty exposed workers were examined (10 smokers, 10 non-smokers) versus 20 controls (6 smokers, 
14 non-smokers). The results obtained showed that the exposed workers had high frequency of CA and SCE compared 
to the controls. In the exposed workers, SCE was nearly two times more frequent than in the controls 
(11.34 ± 4.2 and 5.65 ± 0.9, respectively). On the basis of this result, intervention with oral 
antioxidants was started. SCE frequency significantly decreased to 7.99 ± 2.3 with no significant changes 
of CA. The present results showed that the workers exposed to benzene experienced genotoxic effects manifesting in 
an increase of the frequency of CA and SCE. The study highlights the important role of antioxidants as a preventive 
tool decreasing the level of DNA oxidation, which is a potential cause of human cancer.
Received: 24 August 2006
Accepted: 14 December 2006
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