Sun Jing, Sugiyama Akihiko, Inoue Shota, Takeuchi Takashi, Furukawa Satoshi
Courses of Veterinary Laboratory Medicine, School of Veterinary Medicine, Faculty of Agriculture, Tottori University, 4-101 Koyama-cho Minami, Tottori, Tottori 680-8553, Japan.
J Vet Med Sci. 2014 Mar;76(3):347-54. doi: 10.1292/jvms.13-0457. Epub 2013 Nov 8.
Pregnant rats were treated with 30 mg/kg of methotrexate (MTX) on gestation day 13, and fetal brains were examined histopathologically from 6 to 48 hr after the treatment. In the telencephalon of the control group, there were few pyknotic neuroepithelial cells throughout the experimental period. Six hr after MTX treatment, several pyknotic neuroepithelial cells scattered throughout the telencephalic wall. At 12-36 hr, pyknotic neuroepithelial cells increased significantly and were diffusely distributed throughout the telencephalic wall. Neuroepithelial cells were eliminated and showed sparse cell density at 36 hr in the telencephalon. Almost all fetuses died at 48 hr. Most of the pyknotic neuroepithelial cells were positively stained by the TUNEL method and positive for cleaved caspase-3. While mitotic and phospho-histone H3-positive neuroepithelial cells were located along the ventricular layer of telencephalon in the control group, they were rarely observed in the same region at 6-36 hr in the MTX-treated group. MTX induced few pyknotic changes to neuroepithelial cells in the metencephalon, compared to other parts of brain. The distribution of apoptotic neuroepithelial cells and the time-course changes of the indices of apoptotic and mitotic neuroepithelial cells were different from those of other DNA-damaging chemicals reported previously. The difference may reflect the disparity in mechanisms of apoptosis and the inhibition of cell proliferation in neuroepithelial cells induced by MTX. To our knowledge, this is the first report demonstrating histopathological findings of fetal brain damage induced by MTX.
在妊娠第13天，给怀孕大鼠注射30 mg/kg甲氨蝶呤（MTX），并在注射后6至48小时对胎鼠大脑进行组织病理学检查。对照组端脑在整个实验期间几乎没有固缩的神经上皮细胞。MTX处理6小时后，端脑壁上散在出现一些固缩的神经上皮细胞。在12至36小时，固缩的神经上皮细胞显著增多，并弥漫分布于端脑壁。在36小时时，端脑内神经上皮细胞减少，细胞密度稀疏。几乎所有胎鼠在48小时时死亡。大多数固缩的神经上皮细胞经TUNEL法染色呈阳性，且裂解的半胱天冬酶-3呈阳性。对照组中，有丝分裂和磷酸化组蛋白H3阳性的神经上皮细胞位于端脑的室管膜层，而在MTX处理组的6至36小时，在同一区域很少观察到这些细胞。与大脑其他部位相比，MTX诱导后脑桥神经上皮细胞的固缩变化较少。凋亡神经上皮细胞的分布以及凋亡和有丝分裂神经上皮细胞指标的时间进程变化与先前报道的其他DNA损伤化学物质不同。这种差异可能反映了MTX诱导神经上皮细胞凋亡机制和细胞增殖抑制的差异。据我们所知，这是第一份展示MTX诱导胎脑损伤组织病理学结果的报告。
