Chronic hypoxia is a major cause that increases neonatal mortality in the perinatal period. Vascular endothelial growth factor (VEGF) and its receptors induced by hypoxia are increased blood vessel permeability in the developing central nervous system and characterized as a critical factor in angiogenesis and vasculogenesis. This study investigated the development of the rat cerebellum with expression of VEGF and its receptors under chronic hypoxia in compare with normoxia. In addition, this study can contribute to the understanding of the effect development in the postnatal cerebellum. Rat pups were divided into two groups, normoxia and hypoxia group. The cerebellum of 35-day-old rat was removed and prepared for immunofluorescent staining. After staining, the sections were observed under the fluorescent microscope and were taken the picture using the microscopic-digital camera system. Expression of VEGF and Flk-1 restricted only to Purkinje cells, but feline sarcoma virus-like tyrosine kinase-1 (Flt-1) did not express in all of cerebellar layers. Under chronic hypoxia, expression of VEGF and fetal liver kinase-1 (Flk-1) increased in Purkinje cells but no changes in case of Flt-1. These results suggest that the source of VEGF and Flk-1 is Purkinje cells in the cerebellum. And increase of VEGF and Flk-1 expression in the murine cerebellum results from adaptive responses to chronic hypoxia.

The investigation of the embryonic development of the cerebellum has a long history. The postnatal normal development of the cerebellum in rodents and other animals became a popular topic for morphological investigations nearly a century ago. However, surprisingly, only a few studies are available regarding the prenatal normal development of the rodent cerebellum, especially in guinea pigs. Cell proliferation is essential for the development of the nervous system. The assessment of cell proliferation can be achieved by using various methods. In this study, we investigated the cell proliferation of the cerebellar cortex in guinea pigs at different stages of pregnancy and in postnatal life. Fetuses were obtained by cesarean section at 50 or 60 days of gestation (dg). Immunohistochemistry was performed with proliferating cell nuclear antigen (PCNA) antibody in the cerebellum. Strong PCNA immunoreactivity was observed in the external granular layer (EGL), which is a neurogenic zone in the cerebellum. The proportion of PCNA-IR cells was greater at 1 week than at 60 dg in lobule I, but not lobule VIII. After 50 dg, the width of the EGL continued to decline until 1 week, due to the maturation of the EGL cells. These results demonstrate the pattern of PCNA immunoreactivity in the developing cerebellum of guinea pigs. This serves as a guideline to study abnormal cerebellum development.

The cerebellum is known to control balance, equilibrium, and muscle tone. If the cerebellum becomes damaged, the body is unable to retain its balancing functions or involuntary muscle movement. This is why, in stroke patients, there is a high risk of functional disability, as well as a myriad of other disabilities secondary to stroke. Ischemia was induced in SD mice by occluding the common carotid artery for 5 minutes, after which blood was reperfused. Needle electrode electrical stimulation(NEES) was applied to acupuncture points, at 12, 24, and 48 hours post-ischemia on the joksamri. Protein expression was investigated through caspase-3 antibody immuno-reactive cells in the cerebral nerve cells and Western blotting. The results were as follows: The number of caspase-3 reactive cells in the corpus cerebellum 12 and 24 hours post-ischemia was significantly (p<.05) smaller in the NEES group compared to the GI group. caspase-3 expression 12 and 24 hours post-ischemia was significantly(p<.05) smaller in the NEES group compared to the GI group. Based on these results, NEES seems to have a significant effect on Caspase-3 in the cerebellum in an ischemic state at 12 and 24 hours post ischemia, NEES delays the occurrence of early stage apoptosis-inducing Caspase-3, delaying and inhibiting apoptosis. Further systematic studies will have to be conducted in relation to the application of this study’s results on stroke patients.

Ethanol treatment during the brain growth spurt period has been known to induce the death of Purkinje cells. The underlying molecular mechanisms and the role of reactive oxygen species (ROS) in triggering ethanol-induced Purkinje cell death are, however, largely unresolved. We undertook TUNEL staining, western blotting assay and immunohistochemistry for the cleaved forms of caspase-3 and -9, with calbindin D28K double immunostaining to identify apoptotic Purkinje cells. The possibility of ROS-induced Purkinje cell death was immunohistochemically determined by using anti-8-hydroxy-2'deoxyguanosine (8-OHdG), a specific cellular marker for oxidative damage. The results show that Purkinje cell death of PD 5 rat cerebellum following ethanol administration is mediated by the activation of caspase-3 and -9. However, unexpectedly, TUNEL staining did not reveal any positive Purkinje cells while there were some TUNEL-positive cells in the internal and external granular layer. 8-OHdG was detected in the Purkinje cell layers at 8 h, peaked at 12-24 h, but not at 30 h post-ethanol treatment. No 8-0HdG immunoreactive cells were detected in the internal and external granular layer. The lobule specific 8-OHdG staining patterns following ethanol exposure are consistent with that of ethanol-induced Purkinje cell loss. Thus, we suggest that ethanol-induced Purkinje cell death may not occur by the classical apoptotic pathway and oxidative damage is involved in ethanol-induced Purkinje cell death in the developing cerebellum.

본 연구의 목적은 시각과 운동감각을 이용한 운동 적응의 증거로서 자주 이용되는 프리즘 적응 패러다임에 관련이 있다고 알려진 소뇌의 역할을 밝혀내는 것이다. 프리즘 적응에 관한 행위적 특징들에 관해서는 비교적 많은 연구들이 이루어 졌지만 이 같은 형태의 적응이 발생하게 되는 신경생리학적 기제에 대해서는 아직 연구가 미흡한 실정이다. 이에 본 연구는 두뇌 내의 정보처리 과정 중에서 오류처리에 중요한 역할을 한다고 알려진 소뇌가 이 같은 적응과정에 어떤 역할을 담당하는 가를 측정하기 위하여 경두개자지자극 (Transcranial Magnetic stimulation: TMS) 기법을 이용하였다. 자극부위의 기능을 순간적으로 상실시키는 TMS를 프리즘 적응과정 중 적용한 결과, 전체적인 적응의 양은 통제집단의 적응도와 유의한 차이가 없었으나 프리즘 적응 기간 초기의 정확도가 유의하게 감소함을 발견하였다. 또한 이 같은 정확도의 감소가 운동 동작 중 운동감각의 오류 수정에 문제점이 생기는 것에 기인된다는 사실을 관찰 하였다. 이 같은 결과는 소뇌가 프리즘 적응기제의 하나인 감각 기준틀의 변화에 직접적인 영향을 미친다는 기존의 가설과는 달리, 적응에 있어서 가장 기본 조건인 오류 인식, 수정과정에 직접적으로 관여하며, 적응 그 자체에는 직접적인 영향을 주지 않음을 시사한다.