Study Of The Amino Acid Neurotransmitters Injury Following Lead Exposure During Development Stage

Objective:To investigate the effect of lead exposure on serum amino acids neurotransmitters of rat or children following lead exposure as well as explore the relationship between amino acid neurotransmitter and neurobehavior. Our finding will provide the basis for effect biomarker of lead exposure.Methods: 1. Experimental animal grouping: 60 healthy male and female(1:1) SD rats,were mated Daily check the vaginal plug to make sure pregnant. The pregnant rats were randomly divided into control and lead exposure group. Since the first day of pregnancy,rats in lead exposure group were give lead acetate(100 mg/kg) by gavage until postnatal day 21, PND21. The pups were given the same dose lead until PND42,.Rats in the control group were given same volume saline. 2. A total of 656 children aged 0-6 years old were selected as our subjects, of which, 383 were boys, and 263 were girls. 3.Neurobehavioral test was performed by Mirrors water maze. 4. Conners child behavior scale and self-designed questionnaire were applied to collect the information and neurobehavior. 5. ICP-MS was applied to measure lead content. 6. The content of neurotransmitter amino acids in children’s serum, newborn mouse’s serum and hippocampus were detected by HPLC. 7. Statistical analysis: the data showed for mean±s.Experimental results comparison between the two groups used independent samples t-test(t- test). The comparison between the each group was performed by using single factor analysis of variance(One Way ANOVA) test. Person correlation analysis was used in correlation analysis,and P<0.05 as the difference have statistically significant.Results: 1. There were no significant differences between two groups regarding of body weight in PND1, PND21 and PND42. 2. The escape latency period of PND21 and PND42 offsprings in lead exposure group were longer and the times of crossing the platform was less than those in control group(P<0.05). 3. Compared with control group,blood lead level of PND1, PND2, PND42 were 2.05,10.75 and 40.60 folds than those in the control group, and the difference were statistically significant(P<0.05). 4. compared with control group, Glu content in serum and hippocampus of newborn mouse were significantly higher, and Ser and GABA content were lower. Meanwhile, Gly content showed a decrease trend(P<0.05). 5. The learning and memory ability of PND 21 and PND 42 rat were negatively correlated with the serum content of Glu, Ser, GABA and positively correlated with Gly. 6. The relationships between serum and hippocampus neurotransmitter content wereas followed,Glu(r=0.606,P=0.019),Ser(r=0.384,P=0.033),Gly(r=0.377,P=0.040),GABA(r=0.393,P=0.029).7. The average blood lead content of children was 37.02±22.51μg/L. Blood lead content of boys or girs were37.54±23.66μg/L 36.24±20.66μg/L respectively. Lead content of children with less than3 years old was 29.08±11.57μg/L and 29.08±11.57μg/L for children with 3-6 years old. 8.The relationship between amino acid neurotransmitters and child neurobehavioral: Serum Glu content was positively correlated with children’s impulsive index, index of anxiety or hyperactivity index. Ser content was negative correlation with anxiety index(P<0.05);Gly content was negatively correlated with child anxiety index(P<0.05) and GABA content was positively correlated with children impulse index(P<0.05). 9. Factor analysis about influencing amino acids neurotransmitter. There were different serum Glu and Gly contents of children with different BMI index(P<0.05); Blood lead levels was positively correlated with serum Glu(r=0.087,P=0.026), and negatively related to Ser(r=-0.045,P=0.048) and Gly(r=-0.127, P=0.001). It indicated that bad eating habits was related to children serum levels of GABA and Ser(P<0.05). Bad living had a significant relationship with children’s serum Gly content P<0.05). The distance from home to the main road significantly was significant related to the content of serum Ser(P<0.05).Moreover, factor of factory with oil professional around houses was related to 4neurotransmitters(P<0.05); 10. Multivariate analysis showed that children eating habiting, living habiting, parents profession and education level, surround setting of house, blood lead level were related to detected neurotransmitter contents.Conclusion: Lead exposure results in the increase of blood lead level and changes of amino acid neurotransmitter, thereby affecting the learning and memory ability of offsprigns. The factors including children’s health habits, eating habits, parents and family factors and blood lead level were related to the serum amino acid neurotransmitters.