title: [mRNA expression levels of p53 and DNA damage and repair genes in peripheral blood lymphocytes of benzene-exposed workers].
abstract: OBJECTIVE
  To investigate the relationship between the mRNA expression levels of p53-mediating DNA damage and repair genes in the peripheral blood lymphocytes of workers and their exposures to benzene in their working environment.
  
  
  METHODS
  The mRNA expression levels of p53 and related genes were determined by SYBR Green I chimeric fluorescence quantitative real-time RT-PCR analysis in peripheral blood lymphocytes of 72 workers, who were classified into group A (46 direct exposure to benzene) and group B (26 indirect exposure to benzene) based on their positions, and 29 controls. The differences of gene expression levels were analyzed by software REST 2005. Meanwhile, the peripheral blood leukocytes, hemoglobin and platelet of workers and controls were counted. Benzene content was measured in the samples of toluene, used as raw material, and spraying agents and benzene, toluene and xylene concentrations in the air of workplaces were monitored.
  
  
  RESULTS
  There were no significant differences in the mRNA expression levels of p53, Ku80, Ape1 and Mdm-2 between group A or group B and control group (P > 0.05). The expression up-regulation of p21 mRNA was found, but without significant difference (P > 0.05). However, the mRNA expression levels of Rad51, Bcl-2, Bax, Xpa and Xpc in group A and Rad51 in group B were downregulated significantly (P < 0.05 or P < 0.01). Moreover, both the counts of white blood cell, hemoglobin and platelet in group A were (4.93 +/- 1.27) x 10(9)/L, (123.97 +/- 11.80) g/L and (124.02 +/- 41.22) x 10(9)/L respectively and platelet in group B (135.80 +/- 39.44) x 10(9)/L were significantly lower than in control group (P < 0.05 or P < 0.01).
  
  
  CONCLUSIONS
  The mRNA expression levels of some p53-mediating DNA damage and repair genes are downregulated in the workers chronically exposed to low benzene concentration. The working environment impacts on health of group A workers are greater than the ones of group B.
authors: Hangzhou Center for Disease Control and Prevention, Hangzhou 310006, China.
authors: Rong
authors: R
authors: Ye
authors: Jin-cao
authors: JC
authors: Pan
authors: Jian-zhong
authors: JZ
authors: Cao
authors: Ji-ru
authors: JR
authors: Guan
authors: Xiao-ming
authors: XM
authors: Xie
authors: Ai-xv
authors: AX
authors: Yu
authors: Long
authors: L
authors: Wu
authors: Yue-long
authors: YL
authors: He
authors: Zhao-ling
authors: ZL
authors: Xia
mesh_terms: D000328:Adult; D001554:Benzene / Q000009:adverse effects*; D004249:DNA Damage; D004260:DNA Repair; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D016273:Occupational Exposure / Q000009:adverse effects*; D012333:RNA, Messenger / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D055815:Young Adult
chemical_list: D012333:RNA, Messenger; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D001554:Benzene