2，4- 二氯苯氧乙酸作用的鼠乳对幼鼠蓝斑核中 多巴胺β- 羟化酶表达的影响

Effect of 2, 4-Dichlorophenoxyacetic acid on expression of Dopamine beta hydroxylase in locus coeruleus of neonate rats

摘要:

目的 观察经腹腔注射除草剂2，4- 二氯苯氧乙酸（简称2，4-D）的鼠乳，对幼鼠蓝斑核中多 巴胺β- 羟化酶（DBH）表达的变化，探讨除草剂对神经系统发育的影响。方法 生后7 d 且经母乳喂养的 幼鼠30 只，分成实验组1（10 只）、实验组2（10 只）及对照组（10 只）。实验组1、2 分别按照每天70 及 100 mg/kg 剂量注射2，4-D 至母鼠腹腔（二甲亚砜0.1 ml 做溶剂）；对照组只进行正常鼠乳喂养。待幼鼠哺 乳至第22 天，分别测量其体重、脑重；取幼鼠的蓝斑核进行DBH 免疫染色。结果 ①至生后22 d，实验组2 的幼鼠体重（35.60±2.84）g 与对照组比较（47.21±2.90）g 降低26.8%（P =0.000）；而脑重分别为（1.16±0.05） 和（1.33±0.04）g，实验组2 降低13.1%（P =0.000）；②实验组1、2 幼鼠蓝斑核DBH 相对光密度值为（0.21±0.03） 和（0.19±0.02），低于对照组（0.88±0.38）（P =0.000）。结论 2，4-D 能够抑制幼鼠体重增加；降低幼鼠蓝 斑核DBH 的表达，进而减少脑内去甲肾上腺素的合成，抑制脑及神经系统发育。

Abstract:

Objective To explore the effects of 2, 4-Dichlorophenoxyacetic acid (2, 4-D) on expression of Dopamine beta hydroxylase (DBH) in the locus coeruleus (LC) rats. Methods A total of 307-days-old neonatal rats were randomly divided into 3 groups: group 1 in which maternal rats received 70 mg/kg/day of 2, 4-D for 14 consecutive days (n = 10), group 2 in which maternal rats received 100 mg/kg/day of 2, 4-D for14 consecutive days (n = 10), and control group in which maternal rats did not receive any insults (n = 10). All neonatal rats were breast feeding. Offsprings were sacrificed 22 days after birth and midbrains were harvested for immunohistochemistry staining. Results Rats in group 2 showed a significant reduction of body weight and brain weight when compared with control group (35.60 ± 2.84 g vs 47.21 ± 2.90 g, P = 0.000, 1.16 ± 0.05 g vs 1.33 ± 0.04 g, P = 0.000, respectively). Expression of DBH decreased significantly in group 1 and group 2 when compared with control group (0.21 ± 0.03 vs 0.88 ± 0.38, 0.19 ± 0.02 vs 0.88 ± 0.38, P = 0.000, respectively). Conclusion 2,4-D inhibits the activity of DBH, leading to the decrease of Noradrenaline in the LC of the pups and damage to the nervous system.