| Cytokinesis-block micronucleus (CBMN) test was developed from the traditional method of micronucleus in 1985. With intensive studies on the mechanism of nuclear abnormality, it gradually became a comprehensive method which can fully reflect genetic damage and cytotoxic damage induced by various physical and chemical factors. The cytokinesis-block micronucleus cytome assay was proposed in 1999, then the CBMN cytome was widely used in many fields, including occupational biomonitoring, environmental monitoring and prognostic evaluation of malignant tumors, etc.This study was investigated by two sections, one is systemic analysis on data from published literature of CBMN; the other is laboratory CBMN cytome biomarkers study on representative population. We obtained the reference value and influence factors of CBMN cytome assay markers of peripheral blood lymphocytes in general Chinese population, which can be used to guide the genotoxicity evaluation and risk assessment for population exposed to environmental or occupational chemicals. Our study will provide the basis and reference values for the further related studies.MATERIALS AND METHODS:A full text search was performed in CNKI database with the key words of "micronucleus" and "human", and PubMed database was searched with "cytokinesis-blockmicronucleus", "CBMN", "humans" and "adults", to obtain the articles published at home and abroad from 2001 to 2014. Cytokinesis-block micronucleus (CBMN) assay was applied for micronucleus detection and population not exposed to genotoxicants were established as a control population. Monte Carlo simulation was performed based on the micronucleus frequency, standard deviation, and sample size provided in these articles to calculate the micronucleus frequency for general population and to analyze the influence factors. Selected general population in Anhui province, without occupational exposure to genetic toxicants and no serious disease history, no drug history. Disproportionate stratified sampling according to certain aspects from urban and rural areas, sex, age. Detecting micronucleus cytome markers of peripheral blood lymphocyte, analysis reference value information of each index, and possible influence factors were analyzed and compared by Student’s-t test, Student-Newman-Keuls analysis, general linear regression, Mann-Whitney U test, Kruskal-Wallis H test and negative binomial regression methods according to the data distribution.Part 1:The reference value for micronucleus frequency of peripheral blood lymphocyte in general Chinese populationA total of qualified literatures was 23 in CNKI database and PUBMED database, with an average of 70.6 cases of sample size (22 to 178 cases), the minimum number of micronuclei rate 0.39‰, up to 25.3‰, using Monte Carlo simulation method to simulate the reference micronucleus frequency of Chinese general population for 100 times, the number obtained was 4.36‰,95% upper limit of the reference range of 14.17‰. This part of the study also found a significant effect on the sampling area, gender, smoking and drinking presence of micronucleus rate.Part 2:The reference value for micronucleus cytome markers in general population of Anhui ProvinceWe selected general population by 281 subjects without occupational exposure to genetic toxicants in Anhui region, by rural to urban population ratio of 1:0.9, male to female ratio 6:4. The population age distribution of 18-30 years,31-40 years,41-55 years,56-70 year-old was accounting for a quarter, respectively. The proportions of smoker and drinker were 53.8% and 65.5% in male population, and were 0.9% and 10.0% in female population, respectively. By CBMN assay, we found the micronucleus frequency of Anhui general population was (3.94±3.841)%o (95% CI:0%o-10.24 ‰), the value consistent with average from the part 1. The frequency of nucleoplasmic bridge was 0.17‰ (95%CI:‰～1‰), nuclear buds was 0.55‰ (95%CI:0‰～2‰), nucleus division index was 1.71±0.221 (95%CI:1.28-2.14). After multivariate adjustment by stepwise regression and negative binomial regression, we found drinking status was an independent factor in micronucleus frequency, gender was an independent factor in nucleus division index, smoking and drinking status can to a certain extent affect micronucleus frequency and nucleus division index. We did not find the significant effect of urban and rural areas differences, age and BMI on micronucleus frequency and nucleus division index, and there were no statistically significant factors was observed in nuclear bud and nucleoplasmic bridge frequency.In summary, our study analyzed the domestic research of micronucleus reference value systematically, acquired the reference range for micronucleus frequency of peripheral blood lymphocyte in general Chinese population. We got the reference value of micronucleus, nuclear bud, nucleoplasmic bridge and nucleus division index by stratified sampling in Anhui populatlion. These results can be used as an indicators of these applications and an important reference data to assess individual genetic injury indued by occupational or environmental harmful factors. |
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