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【目的】探讨铅接触大鼠脑组织海马区神经颗粒素表达及在学习记忆障碍中的作用。【方法】32只Wistar大鼠随机分为4组,每组8只,3个染铅组分别在饮用的蒸馏水中添加0.02%、0.10%、0.20%醋酸铅为低、中、高剂量染铅组,空白对照组饮用蒸馏水,连续45 d复制慢性铅中毒模型,对各组进行Morris水迷宫试验,麻醉后分别检测各组动物血铅、脑铅含量;RT-PCR检测海马区组织Ng mRNA、CaMKⅡmRNA表达;免疫组化方法检测P-CaMKⅡ表达,Western Blotting法检测Ng蛋白表达。【结果】1)与空白对照组比较,染铅各组血铅、脑铅含量均显著增高(P<0.01),高剂量组动物体重显著降低(P<0.05);2)Morris水迷宫结果显示,随染铅浓度增高,潜伏期显著延长(P<0.05);通过强化训练,各组动物均获得了一定的定位能力,但各染铅组动物潜伏期显著高于空白对照组(P<0.05);3)与空白对照组比较,各浓度染铅组Ng mRNA及CaMKⅡmRNA表达均显著降低(P<0.05);4)Ng的Western Blotting结果显示,与空白对照组比较,中、高剂量染铅组Ng蛋白表达均显著降低(P<0.01),低剂量组表达也下降,但没有显著差异;P-CaMKⅡ的免疫组化结果显示,与空白对照组比较,低、中、高剂量染铅组表达均显著降低(P<0.05或<0.01)。【结论】Ng作为突触后CaM结合蛋白和PKC的作用底物,参与介导了铅导致的的学习记忆障碍。
【Objective】 To investigate the neurogranin expression in hippocampus of lead exposed rats and its role in learning and memory impairment. 【Methods】 Thirty-two Wistar rats were randomly divided into 4 groups with 8 rats in each group. 0.02%, 0.10% and 0.20% lead acetate were respectively added into drinking distilled water to lead low, middle and high dose lead group , And distilled water was used in the blank control group. The model of chronic lead poisoning was duplicated for 45 days. Morris water maze test was conducted in each group. The content of lead and lead in blood of each group was detected after anesthesia. The expression of Ng mRNA and CaMKⅡmRNA The expression of P-CaMKII was detected by immunohistochemistry and the expression of Ng protein was detected by Western Blotting. [Results] 1) Compared with the blank control group, the levels of lead and lead in blood lead significantly increased (P <0.01), and the body weight of high dose group decreased significantly (P <0.05); 2) Morris water maze results showed (P <0.05). With intensive training, the animals of each group got some localization ability, but the latency of each lead group was significantly higher than that of the blank control group (P <0.05). 3) Compared with the blank control group, the expression of Ng mRNA and CaMKIImRNA in each concentration of lead-exposed group were significantly decreased (P <0.05); 4) Ng Western Blotting results showed that compared with the blank control group, The expression of P-CaMKⅡwas significantly lower (P <0.01), but lower in the low-dose group, but there was no significant difference. The results of immunohistochemistry of P-CaMKⅡshowed that the expressions of P Significantly lower (P <0.05 or <0.01). 【Conclusion】 As a substrate of postsynaptic CaM-binding protein and PKC, Ng is involved in the lead-induced learning and memory impairment.