The relationship between copper-related protein and neurobehavioral function in individuals with occupational exposure to low-level lead / 中国职业医学

ABSTRACT

OBJECTIVE: To analyze the relationship between the neurobehavioral functions of individuals exposed to low-level lead and the levels of serum copper-related proteins glutathione S-transferase M1(GSTM1), hypoxia inducible factor-1 alpha(HIF1α), cyclooxygenase 1(COX1) and metallothionein(MT), and to screen biomarkers for changes in neurobehavioral function caused by occupational lead exposure. METHODS: A total of 194 workers who exposed to low-level lead(lead-exposed group) and 120 workers without lead exposure(control group) were selected from a battery factory as the research subjects by judgment sampling method. The inductively coupled plasma-mass spectrometry was used to determine blood lead levels of the two groups, and the State of Mood Scale(POMS) was investigated to assess the emotional state. The computerized neurobehavioral evaluation system in Chinese version 3(NES-C3) was used to test the neurobehavioral ability index(NAI) of related indicators of learning memory and mental activity. Enzyme-linked immunosorbent assay was used to detect the levels of copper-related protein in serum. After using principal component analysis to extract the principal components of emotional state, learning memory and mental activity, multiple linear regression was used to analyze the influencing factors of neurobehavioral function. RESULTS: The blood lead level of the lead-exposed group was increased [(57.15±11.12) vs(177.86±80.04) μg/L, P<0.01], and the incidence of symptoms such as dizziness, memory loss, sleep disturbance, fatigue, weakness, cold sweats in extremities, cold extremities, tingling of extremities, tingling sensation in the distal extremities, tetany, instability of holding things, metallic taste in the mouth, nausea and vomiting, anorexia, constipation, abdominal distension, abdominal pain, toothache/tooth loosening were increased(all P<0.01) compared with the control group. Meanwhile, the scores of tension-anxiety, depression-dejection, fatigue-inertia, anger-hostility, confusion-bewilderment of POMS were increased(all P<0.01), and the scores of vigor-activity were decreased(P<0.01). The NAI of the lead-exposed individuals in the NES-C3 test of 6 indicators(series addition and subtraction, visual retention, memory scanning, listening to digital breadth, visual simple reaction time, target tracking) were lower than that of the control group(all P<0.01). The serum levels of GSTM1 and HIF1α of the lead-exposed group decreased(all P<0.01), and the COX1 and MT levels increased(all P<0.01) compared with the control group. The serum GSTM1, HIF1α, COX1 and MT of the lead-exposed group were correlated with their emotional state, learning and memory and mental activity to varying degrees(all P<0.05). The results of multiple stepwise linear regression showed that serum COX1 level was an independent influencing factor of emotional state(P<0.01), serum GSTM1, COX1 and lead working years were independent influencing factor of learning and memory(all P<0.05), and work length with lead exposure and alcohol consumption was an independent influencing factor of mental activity(all P<0.05). CONCLUSION: Low-level lead exposure can cause central nervous system symptoms in workers, and the change in neurobehavioral function and serum levels of copper-related proteins GSTM1, HIF1α, COX1 and MT. Serum levels of GSTM1 and COX1 can be used as candidate biomarkers for indicating neurobehavioral function caused by lead exposure.