Cross-Sectional Study On DNA Damage And The MRNA Expression Of Related Regulatory Enzyme In Workers Exposed To Styrene

[Objective]1. To study the styrene worker occupational exposure levels and their occupational healthhazards；2. To study the genetic damage of occupational workers exposed to styrene；3. To analysis the expression levels of mRNA of the DNMTs,HMT,MeCP2, HAT1andHDAC10in different exposure to styrene by quantitative real—time reversetranscription-PCR．This study will provide occupational health surveillance and riskassessment of theoretical basis, by finding the biomarkers of occupational hazards.[Methods]1. To monitor the exposure levels of different exposure-workers by fixed detection andpersonal sampler to obtain exposure dose. And through the survey on occupational healthof workers exposed to styrene and occupational medical examination to get the healthstatus of workers;2. The different exposure levels of styrene exposure-workers were examined bycytokinesis-block micronucleus test to determined the genotoxicity of styrene;3. The mRNA expressions of seven different regulatory enzyme were detected by SYBRGreen I quantitative real—time polymerase chain reaction. Discussion on regulation of epigenetic regulation of related enzymes and to find suitable biomarkers forstyrene-induced occupational health hazard．[Results]1. The occupational health hazards of styrene exposure-workersFixed point and personal detcction show that occupational workers exposed to styreneat high exposure levels.The frequency of cough, dizziness and other symptoms wassignificantly different in exposed and control workers (P <0.05). Exposure to such asacetone, thinner and other organic solvents are risk factors,[OR=8.920,95%CI (3.405,23.368)]. The comparison of the liver function, blood routine, ECG, urine regular andgallbladder and kidney of B-ultrasonography between exposed and control workers did notshow a statistically significant difference（P>0.05）.2. DNA damage detectionThe frequency of lymphocyte micronucleus of exposure group higher than the controlgroup, there was significant difference of the DNA damage degree (P <0.05). Gender didnot affect the frequency of bionuclears micronucleus in the studied groups. No-observedsmoking, alcohol consumption and other factors have an impact on micronucleus rate (P>0.05).3. The mRNA expression of methyltransferase and acylation enzymeThe mRNA of DNMT1, HAT1and HMT were significantly higher in exposure group(P<0.05). The mRNA expression levels of DNMT3a, DNMT3b, MeCP2and HDAC10were no correlated with styrene diffenent groups（P>0.05）.Only male group was observedthe mRNA of HAT1were significantly higher than the control group（P <0.001).Female inboth groups showed higher and significantly different the mRNA of DNMT1and HAT1（Pvalue for0.002,0.001). The results obtained did not show a significant difference betweenexposed males and females when compared with the other regulatory enzymes.[Conclusions]1. Styrene can cause workers such as cough, dizziness and other symptoms occur, andunder the effect of acetone, thinner and other organic solvents will aggravate the body extent of damsge. The physical damage is not obvious for short term styrene exposedworkers, and the damage has yet to be continued observation.2. The frequency of lymphocyte micronucleus of exposure group positively correlatedwith the genotoxicity. Cytokinesis-block micronucleus was used to detect DNA damage ofthe peripheral blood lymphocyte and to be taken as the early phase sensitive biomarker ofthe genetic damage induced by styrene.3. The different mRNA high expression levels of DNMT1, HMT and HAT1in exposuregroup, it suggests that they can be used as the genetic effects of early exposure biomarkers,and the mRNA of other regulatory enzymes such as DNMT3a、DNMT3b、MeCP2andHDAC10did not affect the expression in the studied groups.The mRNA of HAT1highexpression both men and women in exposed group, and the mRNA high expression levelsof DNMT1in female group. And the mRNA of other regulatory enzymes such asDNMT3a, DNMT3b, HMT, MeCP2and HDAC10did not show a significant differencebetween exposed males and females when compared with control groups.