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目的探讨蛋氨酸胆碱对刚断乳SD大鼠铅染毒后海马神经元形态及超微结构损伤的改善作用。方法 40只SPF级SD雄性大鼠随机分为5组:空白组、染铅组、蛋氨酸胆碱组、铅+低、高剂量蛋氨酸胆碱组,4和8周后分别麻醉动物,尾尖采血,原子吸收法测血铅含量;心脏灌注内固定,取海马做石蜡切片、硫堇染色观察海马神经元形态结构,戊二醛再固定,透射电镜观察超微结构。结果铅染毒4、8周后,染铅组大鼠血铅含量分别升高至(274.85±19.51)、(294.32±11.00)μg/L,与染铅组比较,铅+高剂量蛋氨酸胆碱组血铅含量(187.25±16.02,192.68±14.17)μg/L明显降低,差异有统计学意义(P<0.05);硫堇染色和透射电镜结果显示,4周时海马神经元无明显改变;8周时CA1区神经元有缺失、坏死,细胞数量由每3个视野(光镜400×)(306.00±43.05)个减少至(234.86±20.88)个,且超微结构发生改变,蛋氨酸胆碱干预后形态和结构均得到改善,且存在剂量-效应关系。结论铅对海马神经元形态和结构损伤出现较晚,蛋氨酸胆碱可改善铅染毒大鼠海马神经元的形态和结构损伤。
Objective To investigate the effects of methionine choline on the morphous and ultrastructure damage of hippocampal neurons in the newly weaned SD rats after lead exposure. Methods Forty SPF SD male rats were randomly divided into five groups: blank group, lead group, methionine choline group, lead + low and high dose methionine choline group. Animals were anesthetized 4 and 8 weeks later, , The content of lead in blood was measured by atomic absorption spectrometry. The heart was fixed by perfusion and the hippocampus was made into paraffin section. The morphology of hippocampal neurons was observed with thionine staining, the glutaraldehyde was fixed, and the ultrastructure was observed by transmission electron microscope. Results After lead poisoning for 4 and 8 weeks, the levels of lead in blood of lead-exposed rats increased to (274.85 ± 19.51) and (294.32 ± 11.00) μg / L, respectively. Compared with lead-treated rats, lead and high doses of methionine choline The levels of blood lead (187.25 ± 16.02, 192.68 ± 14.17) μg / L were significantly lower than those of the control group (P <0.05). Thionine staining and transmission electron microscopy showed no significant changes of neurons in hippocampus at 4 weeks. The neurons in CA1 area were deleted and necrotic at week 1, the number of cells decreased from (306.00 ± 43.05) to (234.86 ± 20.88) in every 3 fields (light microscope 400 ×), and the ultrastructure was changed. After the shape and structure are improved, and there is a dose-effect relationship. Conclusion Lead forms hippocampal neurons with morphological and structural damage later. Methionine choline can improve the morphological and structural damage of hippocampal neurons in lead-exposed rats.