卫生研究

目的研究慢性铝暴露对脑皮质与外周血淋巴细胞N-甲基-D-天冬氨酸受体1(NMDAR1)的影响,探讨外周血淋巴细胞NMDAR1作为外周血中铝暴露生物标志物的可能性。方法选取2月龄健康雄性清洁级SD大鼠32只,按体重随机分为空白组和铝低、中、高剂量组,空白组饮用自来水,铝低、中、高剂量组分别给予20、120、720 mg/L Al Cl3饮水,大鼠每日饮水约10 m L/100 g,连续染毒360 d。染毒结束,采用石墨炉原子吸收法测定血浆铝和脑铝含量,采用实时荧光定量聚合酶链反应法(RT-PCR)测定脑皮质与外周血淋巴细胞中NMDAR1基因相对表达量,酶联免疫吸附法(ELISA)测定脑皮质和外周血淋巴细胞中NMDAR1蛋白含量。结果对照组及铝低、中、高剂量组血浆铝含量分别为69.88、83.10、87.06和134.60μg/L,铝低、中、高剂量组高于对照组,差异有统计学意义(P<0.05);脑铝含量分别为0.065、0.102、0.139和0.228μg/mg,铝低、中、高剂量组高于对照组,差异有统计学意义(P<0.05)。NMDAR1基因表达随铝剂量升高呈下降趋势,脑皮质基因相对表达量铝中、高剂量组低于对照组(P<0.05);外周血淋巴细胞NMDAR1基因表达铝中、高剂量组低于铝低剂量组和对照组(P<0.05),铝中、高剂量组之间比较差异无统计学意义(P=0.167)。脑皮质NMDAR1蛋白含量铝高剂量组低于对照组、铝低剂量组(P<0.05);铝中剂量组低于对照组(P<0.05);淋巴细胞NMDAR1蛋白含量铝高剂量组低于对照组、铝低剂量组(P<0.05),与铝中剂量组比较差异无统计学意义(P=0.159)。结论慢性铝暴露可影响大鼠脑皮质与外周血淋巴细胞NMDAR1基因相对表达量和蛋白表达,随铝剂量的增加基因相对表达量和蛋白表达下降,可将NMDAR1作为铝暴露外周生物标志物进一步研究。

Objective To study the impact of the chronic aluminum exposure on Nmethyl-D-aspartate receptor 1( NMDAR1) in the cortex and peripheral blood,and to explore the possibility that whether NMDAR1 of peripheral blood lymphocytes could be taken as a biomarker of aluminum exposure. Methods Thirty-two cleaning degree,healthy and male SD rats were randomly divided into four groups by weight,i. e. controlgroup,low-dose group,mid-dose group,and high-dose group separately. Different doses of Al Cl3( 20,120 and 720 mg /kg) were added into the rats' drinking water,and control group was given tap water,each rat approximately drink 10 m L /100 g,the experiment lasted 360 days. Then,plasma aluminum and cortex aluminum were measured by atom absorption spectrometry with graphite furnace( GFAAS),relative expression of NMDAR1 gene was assayed by real-time fluorescence quantitative polymerase chain reaction( RTPCR) and NMDAR1 protein both in the cortex and peripheral blood lymphocytes were assayed by enzyme-linked immunosorbent( ELISA). Results Plasma aluminum increased with the increase of Al exposure dose( P < 0. 05),the result of plasma aluminum were69. 88,83. 10,87. 06 and 134. 60 μg / L,respectively,plasma aluminum in low-dose,mid-dose and high-dose group were significant increased,compared to the control group.Cortex aluminum increased with the increasing of aluminum dose( P < 0. 05),the result of cortex aluminum were 0. 065,0. 102,0. 139 and 0. 228 μg / mg,respectively. The differences among groups were significant( P < 0. 05). The expression of NMDAR1 gene both in the cortex and peripheral blood lymphocytes were reduced with the increasing of aluminum dose( P < 0. 05). The differences of gene expression in the cortex among the three groups were significant statistically( P < 0. 05). The differences of gene expression in peripheral blood lymphocytes among the three groups were significant statistically( P <0. 05),but there was no significantly statistical difference between mid- and high-dose group( P = 0. 167). The protein level of NMDAR1 in the cortex was obviously reduced in high-dose group,compared to that in the control and low-dose group( P < 0. 05). The protein level of NMDAR1 in the peripheral blood lymphocytes were significantly reduced,compared to that in the control and low-dose group( P < 0. 05),the protein level of NMDAR1 in the peripheral blood lymphocytes in the mid- and high-dose group was not different from one another( P = 0. 159). Conclusion Chronic aluminum exposure could severely impaire the gene expression and protein expression of NMDAR1 both in the cortex and peripheral blood lymphocytes. With the increasing of the aluminum dose, gene expression and protein expression of NMDAR1 are decreased. The NMDAR1 could be taken as a peripheral biomarker of aluminum exposure for further research.