| ?Objective?This study aims to research the influence of hard metal dust exposure to the level of serum Galectin 3(Gal-3). To explore the role and probable mechanism of Gal-3 in lung fibrosis caused by hard alloy dust. To investigate the feasibility of Gal-3 to be a serological marker of exposure to hard metal dust. ?Methods?Selected 89 workers who undertake hard metal related material's sieving, mixing and grinding to be the exposure group. All workers came from one enterprise which engaged in cemented carbide production in Shandong province. 89 persons who didn't contact dust were selected to be the control. Questionnaires were used to get subjects' occupational history,past disease history and so on. The emphasis of the survey was respiratory symptoms. Carried out routine occupational health examination to subjects. Enzyme-linked immunosorbent assay(ELISA) was used to measure concentration of serum Gal-3,Transforming growth factor ?(TGF-?)?Immunoglobulin E(IgE)?CCAAT enhancer binding protein(CEBP?)?Nuclear factor-?B(NF-?B). Used individual sampling method to collect air samples of exposed workers. Flame atomic absorption spectrometry was used to measure air cobalt concentration which represented external exposure dose. Graphite furnace atomic absorption spectrometry was used to test concentration of urine cobalt which represented internal exposure dose. Used Epidata3.1 software to entry data. SPSS17.0 was used to analyze data. ?Results? 1 Analysis of occupational health examination results of the two groups 1.1 Basic situation of all subjectsThere were 89 workers in exposed groups which consist of 39 sieving material workers, 40 mixing workers and 10 grinding workers. There were 70 male and 19 female in the group, whose ages were from 25 to 58 with an average of(40.70±8.46) years. Dust exposure lengths of service were from 2 to 39, the median were [9(4, 21.50)] years. The control group consisted of 61 male and 28 female, whose ages were from 26 to 60 with an average of(38.58±9.05) years. Dust exposure lengths of service were from 1 to 36, the median were[7(3, 16)] years. 1.2 Compare health status of the two groupsThere were higher incidence of respiratory symptoms which included shortness of breath, chest tightness, cough and expectoration in exposed group workers than that of the control group workers(P < 0.05).Exposed groups' imaging abnormalities detection rate were higher than that of the control group(?2=69.34,P?0.05). Lung function test results showed that forced vital capacity accounted for the percentage of the predicted value(FVC%) and the first second forced expiratory volume accounted for the percentage of the predicted value(FEV1%) of exposed group were lower than that of the control group(P?0.05). FEV1/FVC% showed no statistically significant differences between two groups(t=1.52,P?0.05). There were no significant differences of the numbers of white blood cell, neutrophil cell, lymphocytes, monocytes and eosinophils as well as the abnormal increases rates of the cell numbers between the two groups(P > 0.05). 2 Comparison of serum Gal-3 levels between two groupsSerum concentration of Gal-3 in the exposure group was(9.81±4.39) ng/m L; the average concentration in the control group was(7.34±3.60) ng/m L. T test revealed that the serum Gal-3 level of exposed group was higher than that of control group(t=4.11,P?0.05). 3 Correlation analysis between serum Gal-3 and air cobalt concentrationSetted individual sampling points according to the type of work. There were 4?4?3 points in sieving material post, mixing post and grinding post respectively. Air cobalt concentration detection results showed that three types of workers had air cobalt exposure level ranges respectively to be 0.01~0.02mg/m3,0.09~1.04mg/m3 and 0.02~0.18mg/m3; had mean levels respectively to be [0.01(0.01,0.01)]mg/m3, [0.63(0.21,0.96)]mg/m3,[0.16(0.02,0.19)]mg/m3? There were significant differences of the average cobalt concentration among three types of workers(H=7.52, P < 0.05), of which mixing workers had the highest exposure levels. Comparisons were putted out between different two types of workers, the result showed that exposed levels of sieving material workers were significant different with other workers(P< 0.05). There were no significant differences of exposed levels between mixing workers and grinding workers(P > 0.05). Merged mixing and grinding workers to be the higher exposure group and the sieve material workers to be the lower exposure group. There were significant differences of exposed levels between higher and lower exposure groups(t=2.38,P<0.05). Spearman rank correlation analysis showed that individual air cobalt concentration correlated with serum Gal-3 concentration in exposed group(rs=0.62,P<0.05). 4 Correlation analysis between serum Gal-3 and urine cobalt concentrationsThe urine cobalt concentration of the exposure group was 0.22~38.24?g/L, median was [4.69(2.31, 7.94)] ?g/L. Urine cobalt concentration of the control group was 0.02~2.70?g/L, median was [0.22(0.22, 0.42)] ?g/L. According to15?g/L urine cobalt limit specified by American Conference of Governmental Industrial Hygienists(ACGIH), 9 workers in exposure group had excessive concentrations of urine cobalt(10.11%). Spearman rank correlation analysis of serum Gal-3 and urine cobalt concentration in exposure group showed that they had correlation(rs=0.23,P?0.05). 5Correlation analysis between serum Gal-3 and TGF-? ? IgE ? CEBP? and NF-?B concentrationsLevels of serum TGF-??IgE?NF-?B and CEBP? in exposure group were higher than those in control group(t=2.97;3.62;3.73;3.99,P?0.05). Pearson correlation analysis showed that Gal-3 and TGF-??IgE?NF-?B?CEBP? were correlated in exposed group(r=0.70, 0.29, 0.37, 0.57; P < 0.05).There were correlation between TGF-? and CEBP?(r=0.49,P?0.05), IgE was correlated with NF-?B(r=0.38, P < 0.05); IgE was also related to CEBP ?(r=0.25, P<0.05).In order to eliminate the effect of related indexes, partial correlation analysis was carried out to analysis related indexes. The results showed that Gal-3 and TGF-? were related(r=0.59,P?0.05), Gal-3 and CEBP? were still correlated(r=0.29, P < 0.05). IgE and NF-?B still had correlation(r=0.29, P < 0.05). TGF-? and CEBP? had relation(r=0.30, P < 0.05).Pearson correlation analysis in the control group showed that Gal-3?TGF-??IgE?NF-?B?CEBP? were not related(P > 0.05). 6 Analysis of influencing factors of serum Gal-3All subjects were contained to be the target population. Level of serum galectin-3 was selected to be dependent variable, many indexes were selected to be independent variables which concluded exposed to hard alloy dust or not; gender, age, length of service, smoking or not, abnormal image manifestation of increased texture ro?gh?point shadow?linear shadow and grid shaped shadow or not, abnormal lung function results or not, TGF-??IgE?NF-?B ?CEBP?. The stepwise regression method was used to put out multiple linear regression analysis about the influencing factors of Gal-3.The results were as follows: whether exposure to hard alloy dust, age, smoking, serum level of TGF-? and CEBP? acted as main factors to affect Gal-3 level..?Conclusions?First, concentration of serum Galectin 3 increases by exposing to hard metal dust.Second, Gal-3 has positive association with TGF-? and CEBP?. Gal-3 can promote TGF-? to contribute to pulmonary fibrosis. It can also elevate CEBP?, which is important factor acting in PI3K/Akt signaling pathway to stimulate the selective activation of macrophages to M2 type to promote the progress of fibrosis.Third, use urine cobalt levels to represent the internal exposure dose of hard metal dust exposure and use individual air cobalt concentrations to represent external exposure dose. Gal-3 has correlation with both external and internal exposure concentrations. This prompts that Gal-3 can be used as a serological marker of hard alloy dust exposure. |
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