Abstract：Objective The aim of our study was to investigate the influence of hexavalent chromium exposure on mRNA expression of cell cycle related genes in electroplating workers,and to provide population data for investigating the toxic mechanisms of hexavalent chromium. Methods A total of 155 cases of workers occupationally exposed to hexavalent chromium were selected,including 89 males and 66 females,and the average age of workers was 39.65±8.856 years old. Questionnaire was used to collect essential information of workers. Peripheral blood was collected from electroplating workers. The inductively couple plasma mass spectrometry（ICP-MAS）was used to measure total blood chromium content. The workers were divided into four groups according to the blood chromium content. After extracting total RNA from whole blood and reverse transcription,the mRNA expression levels of p16 and CDK6 genes were detected by real-time quantitative PCR. Meanwhile,the levels of blood chromium （BCr）and the mRNA expression of p16 and CDK6 genes were compared among four groups. The impact of BCr,smoking habits,drinking habits,gender on the mRNA expression of CDK6 gene was analyzed. Results The levels of BCr in group 1 to 4 were 0.04ppb,0.47±0.29 ppb,2.76±1.16 ppb,9.36±4.38 ppb,respectively,and the difference between every two groups was significant （P<0.05）. The median of p16 gene expression in four groups was 4.22,7.19,7.47,and 14.60,respectively,and the difference between every two groups was not significant （P>0.05）. The mRNA expression levels of CDK6 gene in groups 2 to 4 were 15.05,8.03 and 24.81,respectively,which were significantly higher than that in group 1 （P<0.05）. The results of logistic regression showed that the level of Bcr was the main influence factor,while smoking habits,drinking habits and gender had no obvious impact on the mRNA expression of CDK6 gene. Conclusions Long-term exposure of hexavalent chromium led to higher mRNA expression of CDK6 gene,and it may serve as a biomarker for workers occupationally exposed to hexavalent chromium.
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