Radiation Effects on the Ultrastructure of Rat Cerebellar Cortex / 대한해부학회지

Severe irradiation on head may result functional alterations of central nervous system. In this study, the irradiation effect on the cerebellar cortex following heavy X-irradiation on head was studied ultrastructurally. Radiation was produced with the linear accelerator ML-4MV[Mitshubishi Co.], and rats weighing about 200gm each were exposed their heads within the radiation areas of 30cm x 30cm, under the radiation distance of 80cm, and with the radiation depth of 1.2 cm. Radiation doses were 3,000rads or 6,000rads, respectively. Animals were sacrificed on 6 hours, 2 days or 6 days following the radiation. Under anesthesia, animals were perfused with 1% glutaraldehyde-1% paraformaldehyde solution. Two hours after the perfusion, brain were taken out and refixed over night in the perfusion fixative. Small blocks of cerebellar hemispheric cortices were refixed 2 hours in 2% osmium tetroxide solution. Fixed tissues were dehydrated in alcohol, embedded in araldite mixture, and cut with ultratome. Ultrathin sections were contrasted with uranyl acetate and lead citrate solutions, and observed with electron microscope. The results obstained were as follow : 1. On 6th hour following X-irradiations, many cerebellar cortical neurons showed increased electron densities, more complicated nuclear infoldings, depletion of synaptic vesicles, expansion of astroglial territories, etc. 2. On 2nd day following X-irradiations, many organelle-rich cells such as Purkinje cells and Golgi cells were darkly degenerated. Numerous myelin figures formed by the cisternal fusions of Golgi apparatus or granular endoplasmic reticula were observed. Cytoplasmic processes of activated astroglial cells were expanded around capillaries and between granule cells. 3. On 6th day following X-irradiations, morphology of neuropil and neurones in the cerebellar cortex was generally restored, except the expanded territories of astroglial cells. From the above results, it was concluded that the release ofneurotransmitters and transcapillary leakage of blood substance were occurred on 6 hours after heavy X-irradiations. And severe alterations were produced on 2 day after X-irradiation, but the condition was generally restored on 6th day following X-irradiation.

Effects of BCG Treatment on the Mouse Thymic Cortex : An Electron Microscopic Study / 대한해부학회지

This experiment was performed to study the morphological responses of the thymic cortex of the mice after administration of BCG. Healthy adult mice weighing 25gm each were divided into normal and experimental groups. BCG[0.03X108-0.32X108 CFU] were injected subcutaneously to the animals every other day, and animals were sacrificed at 4 days, 1 week, 2 weeks and 8 weeks following the first injection. Thymus were removed immediately after sacrifice and transferred to cold phosphate buffered 2.5% glutaraldehyde-1.5% paraformaldehyde solution[pH 7.3], and cut into small pieces. Tissue samples were fixed for 2-3 hours in the same fixative, postfixed with phosphate buffered 1% osmium tetroxide solution[pH 7.3], dehydrated in a graded series of alcohol, and embedded in araldite mixture. Ultrathin sections stained with uranyl acetate and lead citrate were observed with a JEM 100CX-II electron microscope. The observed results were as follow : 1. In the early BCG treated groups, a few eosinophile leucocytes were observed, but more eosinophils were observed in later groups. Some elongated and bar-shaped lysosomes with eletron lucent gap were often obserced in the macrophages. 2. Cortical population of thymocytes in the thymus were reduced, whereas territoris of the epithelial reticular cells were expanded especially in 2 weeks and 8 weeks groups. Some portion of the thymic cortex exhibited large intercellular spaces, and a few nuclear bodies filled with materials of medium density were observed in the epithelial reticular cells. 3. In the 8 weeks groups, macrophages, plasma cells and eosinopile leucocytes and developing eosinophile leucocytes were often observed in the thymic cortex. Distended cisternae of granular endoplasmic reticula and newly forming prosecretory granulses in the Golgi complex were ovserved in som plasma cells. From the above results, it was suggested that repeated treatment with BCG could induce disturb the maturation and differentiation of the T lymphocytes. In turn, BCG, if repeatedly injected, may disturb the immunological medchanism.