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目的:探讨氯化甲基汞(MMC)致大鼠不同发育阶段脑组织形态结构改变。方法:雌性Wistar大鼠体重(120±20)g,随机分为3个实验组和对照组各30只。3个实验组母鼠从妊娠前90天至仔鼠出生后30天连续喂饲含有不同剂量(0.75、1.50和3.00 mg/kg)MMC的普通饲料,对照组给予普通饲料。脑切片经苏木精-伊红染色,在光镜下观察长期接触低剂量MMC仔鼠脑组织形态结构。采用荧光原位末端标记法,在激光共聚焦显微镜下计数两组生后不同时间点仔鼠大脑、小脑和海马发生凋亡的神经元,以PCD阳性率表示凋亡的多少。结果:在实验设计的接触剂量下,仔鼠大脑、小脑和海马神经元体积缩小、固缩,核染色质致密等凋亡形态特征。实验组和对照组生后不同时间点仔鼠脑神经元都存在凋亡。结论:大鼠长期低剂量接触不同浓度MMC可使其生后仔鼠大脑、小脑和海马部分神经元出现凋亡形态学改变,随仔鼠脑汞含量升高神经元凋亡率明显增加。
Objective: To investigate the morphological changes of brain tissue at different developmental stages induced by methylmercury chloride (MMC) in rats. Methods: Female Wistar rats weighing (120 ± 20) g were randomly divided into 3 experimental groups and 30 control groups. Three experimental groups of rats were fed with normal diet containing different doses of MMC (0.75, 1.50 and 3.00 mg / kg) continuously from 90 days before gestation to 30 days after the birth of the offspring. The control group was given normal feed. The brain sections were stained with hematoxylin-eosin, and the morphological structure of brains of low dose MMC rats were observed under light microscope. Fluorescence in situ end labeling was used to detect the apoptosis of neurons in cerebellum, cerebellum and hippocampus of the two groups at different time points after laser confocal microscopy. Results: Under experimental dose, the neurons in the brains, cerebellum and hippocampus of the offspring were reduced in size, condensed and chromatin condensed. There were apoptosis in the neurons of the offspring in experimental group and control group at different time points after birth. CONCLUSIONS: Long-term low-dose exposure to different concentrations of MMC in rats can induce apoptotic morphological changes in some neurons in the brains, cerebellum and hippocampus of postnatal rats. Neuronal apoptosis increased significantly with increased brain mercury levels in the offspring.