Pathologic study on tissue anomalies in the developing brain

众所周知，地方性克汀病的突出症状是侏儒、耳聋和智力迟钝。本研究的目的是观察地方性克汀病患者和实验性克汀病大鼠脑组织的病理形态学改变。对黑龙江集贤乡6例地方性克汀病患者小脑皮质进行了组织学研究。检查发现颗粒层内颗粒细胞密度增加，髓鞘稀疏。免疫组化显示小脑深部分子层和颗粒层对髓鞘碱性蛋白的反应性降低。颗粒细胞密度增高可能与小脑肾小球发育不全及颗粒层髓鞘形成不足有关.用佳木斯市地方性克汀病高发区的水和当地特产配制的饲料喂养缺碘大鼠。Experi ...更多信息 在高知也使用了抗甲状腺药物甲巯咪唑。母鼠在妊娠期和分娩后均喂以营养不良饲料。在实验的第1天-一年，用相同的饮食喂养它们的后代。(1)光镜观察显示，与正常大鼠相比，甲状腺功能减退大鼠的颗粒细胞层突触素反应性降低，颗粒细胞密度增加。电子显微镜显示，在小脑肾小球乙醇磷钨酸阳性突触连接的密度和数量减少。这一发现似乎与突触素免疫反应性降低有关。(2)碘缺乏导致耳蜗结构发育迟缓和细胞变性。这些变化可能与地方性克汀病耳聋的发病机制有关.结果提示碘缺乏或甲状腺功能减退对小脑皮质和内耳细胞分化有影响。需要进一步的研究来评估碘缺乏对大脑发育的全面影响。少

It has been well known that in endemic cretinism, the outstanding symptoms are dwarfism, deafness, and mental retardation. The propose of the present study was to examine pathomorphologic changes of brains in endemic cretinism patients and experimental cretin rats.1. Histopathological study was made on cerebellar cortex of six patients with endemic cretinism in Jixian village, Heilongjiang, China. Examination revealed increased density of granule cells and sparse myelin sheath in the granular layer. Immunohistochemistry, showed lowered reactivity to myelin basic protein in the deep molecular layer and granular layer of cerebellum. Increased density of granule cells in the patients seems to be related to underdevelopment of cerebellar glomeruli and deficient myelination in the granular layer.2. Experiment was performed on iodine deficient rats fed in Jiamusi with a diet made of the local agricultural products and drinking water from an area of high incidence of endemic cretinism. Experi … More ments were made also in Kochi using antithyroid drug, thiamazole. The mother rats were fed with the deficient diet during pregnancy and after delivery. Their offsprings fed on the same diet were sacrificed on day 1-one year of The experiments.(1) Light microscopy showed lower synaptophysin reactivity in the granule cell layer and increased density of granule cells in hypothyroid rates as compared to normal rats. Electron microscopy exhibited reduced density and number of ethanolic phosphotungstic acid-positive syanptic junctions in the cerebellar glomeruli. This finding seems to be related to lowered synaptophysin immunoreactivity.(2) Iodine deficiency led to a sluggish development and cellular degeneration of cochlear structures. These changes might be related to the pathogenesis of deafness of human endemic cretinism.3. The results suggest that iodine deficiency or hypothyroidism has effcts on cellular differentiation of cerebellar cortex end inner ear. Further studies are required to assess the full effects of iodine deficiency on the brain development. Less