低剂量γ—射线照射孕鼠导致生后三天大鼠脑的异常改变

ABNORMAL CHANGES IN THE RAT BRAIN AT POSTNATAL DAY 3 INDUCED BY LOW DOSE OF GAMMA RADIATION OF THE MOTHER RAT AT THE 13TH DAY OF PREGNANCY

本文采用克紫(cresyl violet)染色和免疫细胞化学方法对在受孕13天时接受一次^(60)Co(1.0GY)γ-射线全方位照射的大鼠所生的鼠仔,在生后三天时观察了其脑内部结构的改变。照射组侧脑室背侧和海马背侧,出现大小不等、形态各异、排列紊乱并聚集成异常结节样的细胞团。细胞团内偶见S-100和神经元特异性烯醇化酶(NSE)免疫阳性细胞,未见生长抑素、亮氨酸脑啡肽、后卟加压素和血管活性肠多肽免疫阳性细胞分布。此四种活性物质在脑内异常结节样细胞团以外的分布,以照射组免疫阳性细胞数目、分布区域、以及细胞胞体内免疫阳性颗粒少于正常对照组为主要特征。从总体上来看,小剂量的γ-射线照射孕鼠对大鼠脑生后发育是有影响的,其放射损伤是器质性病变,不可逆的。

It was studied by using cresyl violet stainning and immunocytochemical method that the abnormal changes in the Wistar rat brain of the postnatal day3 induced by single, low dose of Gamma radiation (^(60)Co 1 GY) at the 13th day of pregnancy in all directions. Ectopic cell nodules appeared dorsal to the hippocampus and the lateral ventricle in different size and shape. The cells in the nodule were irregularly arranged. S-100 and neuron specific enolase (NSE) immunoreactive cells were occasionally seen and no somatostatin (SOM), L-enkephalin (L-ENK), vassopressin (VAS) and vasoactive intestinal polypeptide (VIP) immunoreactive ceils were detected in the cell nodules. Whereas many S-100 and NSE immunoreactive cells were found in other regions of the rat brain except the superficial layers of the neocortex. It is a primary character that thenumbers of the SOM-, L-ENK-, VAS- and VIP-immunoreactive neurons, the granules within the cytoplasm and the distributive regions in the radiation groups were less than those in the control materials. These results elucidate that the low dose gamma radiation at the 13th day of pregnancy could conduce to slow development of the neonatal rat brain and irreversible ectopic cell nodules.