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目的探讨发育期慢性低浓度铅暴露对仔鼠海马Homer1b/c蛋白表达变化与学习记忆能力的关系。方法 30只孕鼠按体重随机分为3组,分别给予双蒸水(对照组)、0.05%、0.20%醋酸铅饮水(低、高剂量染铅组),断乳后仔鼠自行饮用含铅水至生后28 d,生后56 d采用跳台试验测试仔鼠学习记忆能力;Western blot法检测仔鼠生后7、14、21、28 d海马Homer1b/c蛋白表达;血铅和海马脑铅含量用原子吸收光谱法测定。结果对照组、0.05%、0.20%醋酸铅组仔鼠跳台试验逃离潜伏期分别为(25.71±4.56)、(39.67±5.18)、(64.82±9.73)s,停留潜伏期分别为(234.89±25.85)、(147.15±19.26)、(83.56±14.52)s,与对照组比较,各剂量染铅组仔鼠逃离潜伏期明显延长、停留潜伏期明显缩短(P<0.05);与对照组比较,生后7、14、21、28 d时,0.05%和0.20%醋酸铅组仔鼠海马Homer1b/c蛋白表达分别为(0.607±0.022)、(0.825±0.054)、(0.583±0.015)、(0.557±0.011)和(0.540±0.021)、(0.574±0.018)、(0.471±0.009)、(0.412±0.007)明显降低(P<0.05)。结论慢性铅暴露可降低仔鼠被动回避反应的学习和记忆能力,其机制可能与染铅所致仔鼠海马Homer1b/c蛋白表达下降有关。
Objective To investigate the relationship between the expression of Homer1b / c protein and the ability of learning and memory in the hippocampus of offsprings of rats exposed to chronic low-level lead exposure. Methods Thirty pregnant rats were randomly divided into three groups according to their body weight, and received distilled water (control group), 0.05%, 0.20% lead acetate drinking water (low and high dose lead exposure group). After weaning, 28 days after birth, and 56 days after birth, the ability of learning and memory of offspring was tested by step-down test. The protein expression of Homer1b / c in hippocampus was detected by Western blot in 7, 14, 21 and 28 days after birth. By atomic absorption spectrometry. Results In the control group, the escape latency of offspring in test group (0.05%, 0.20% lead acetate) were (25.71 ± 4.56), (39.67 ± 5.18) and (64.82 ± 9.73) s respectively, and the latency to stay was 234.89 ± 25.85 and 147.15 ± 19.26) and (83.56 ± 14.52) s, respectively. Compared with the control group, the escape latency of the offspring in each dose of lead exposure group was significantly prolonged and the latency to stay was significantly shorter (P <0.05). Compared with the control group, At 28 days, the protein expression of Homer1b / c in hippocampus of offspring of 0.05% and 0.20% lead group were (0.607 ± 0.022), (0.825 ± 0.054), (0.583 ± 0.015), (0.557 ± 0.011) and (0.540 ± 0.021 ), (0.574 ± 0.018), (0.471 ± 0.009) and (0.412 ± 0.007) decreased significantly (P <0.05). Conclusion Chronic lead exposure may reduce the learning and memory abilities of passive avoidance in offspring rats. The mechanism may be related to the decreased expression of Homer1b / c protein in the hippocampus of offspring induced by lead.