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目的研究孕哺期染铝对仔鼠长时程增强(LTP)和谷氨酸(Glu)含量影响,探讨铝对发育中中枢神经系统毒性作用及机制。方法 Wistar大鼠怀孕起染AlCl3至仔鼠哺乳期结束,共计6周,原子吸收石墨炉法测定血铝和脑铝含量;细胞外微电极技术测定LTP;免疫组化法测定海马谷氨酸含量。结果 0.2%AlCl3组仔鼠血铝和脑铝分别为(47.43±14.38)mg/L、(13.86±6.60)mg/g;0.4%AlCl3组血铝和脑铝为(55.56±19.07)mg/L、(18.79±5.18)mg/g,与对照组[(33.89±8.74)mg/L,(7.61±3.44)mg/g]比较,血铝、脑铝含量均明显增加(P<0.05);CA1区LTP的诱导和维持明显受到抑制,其群体峰电位幅值增强率明显低于对照组(P<0.01)。孕哺期铝暴露使仔鼠海马内谷氨酸含量下降(P<0.05)。CA1区对照组,0.2%AlCl3组和0.4%AlCl3组谷氨酸平均吸光度(A)值分别为(0.35±0.02)、(0.33±0.02)、(0.29±0.03),阳性面积比分别为(5.06±1.36)、(4.70±0.56)、(1.71±0.23)。结论孕哺期铝暴露可以使仔鼠海马CA1区LTP的诱导和维持受到抑制,谷氨酸水平下降。
Objective To study the effects of aluminum on the long-term potentiation (LTP) and glutamic acid (Glu) contents in offsprings during pregnancy and lactation, and to explore the toxic effects of aluminum on developing central nervous system and its mechanism. Methods Wistar rats were pregnant with AlCl3 from the end of pregnancy to the end of the pups lactation, for a total of 6 weeks. Atomic absorption method was used to determine the contents of ALP and ALA. LTP was determined by extracellular microelectrode technique. Glutamate levels were measured by immunohistochemistry . Results The blood aluminum and brain aluminum of the 0.2% AlCl3 group were (47.43 ± 14.38) mg / L, (13.86 ± 6.60) mg / , (18.79 ± 5.18) mg / g respectively, compared with control group [(33.89 ± 8.74) mg / L, (7.61 ± 3.44) mg / g] The induction and maintenance of LTP in the region were significantly inhibited, and the enhancement rate of the population peak potential amplitude was significantly lower than that of the control group (P <0.01). Exposure to aluminum during pregnancy led to a decrease in glutamate levels in the hippocampus (P <0.05). The average glutamic acid absorbance (A) value of CA1 zone control group, 0.2% AlCl3 group and 0.4% AlCl3 group were (0.35 ± 0.02), (0.33 ± 0.02) and (0.29 ± 0.03) ± 1.36), (4.70 ± 0.56), (1.71 ± 0.23) respectively. Conclusion Aluminum exposure during pregnancy and lactation can inhibit the induction and maintenance of LTP in hippocampal CA1 region of the offspring, and decrease the glutamate level.