大鼠大脑皮质、白质毛细血管老年性改变的研究

发布时间：2018-10-31 18:34

【摘要】： 老年人普遍存在记忆、认知功能的下降。导致老年大脑记忆、认知功能下降的机制是多方面的。其中,血管因素可能是造成老年大脑功能衰退的重要机制之一。大脑毛细血管是脑血管树的最细小分支互相吻合而成的一个三维网状结构,对调节大脑微环境、维持局部脑血流量起重要作用,毛细血管周围微环境中神经元的正常功能活动、神经冲动的有效传递等均有赖于毛细血管完整的形态结构。已有大量的定性研究深入细致的观察了老年大脑不同部位毛细血管形态的变化,如毛细血管扭曲、球形改变及线样改变等大体形态的变化,以及内皮细胞萎缩,基膜增厚,足细胞退化等超微结构改变。而关于大脑毛细血管的定量研究较少,且多限于大脑皮质、海马等部位。近年来,运用新的体视学方法的研究发现正常老年大脑并不存在显著性大脑皮质神经元死亡。那么,皮质毛细血管是否发生老年性改变?尽管有过此方面的研究,但这些研究的结果差异较大,且均没有贯彻现代体视学方法的原理。此外,运用体视学方法的研究结果表明老年大脑白质体积发生显著性萎缩,白质内有髓神经纤维的总长度显著下降。此时,白质毛细血管发生了那些改变?国内外尚未见报道。因此,基于对以往皮质毛细血管老年性改变的研究不足之处的总结以及对白质毛细血管老年性改变这一空白区域的补充,本实验以大鼠作为动物模型,利用体视学定量研究方法和免疫组化技术对大脑皮质、白质内毛细血管的老年性改变进行了研究。第一部分大鼠大脑皮质毛细血管老年性改变的体视学研究 1材料与方法 1.1雌性Long-Evans大鼠,青年组(7月龄)10只,老年组(27月龄)10只。 1.2将大鼠麻醉灌注固定后,从每只大鼠随机抽取一侧大脑半球,制作2 mm厚的连续脑组织块,从每个脑块切取一张4μm厚的各向同性切片,进行免疫组化染色。在100倍油镜下从每张切片皮质区域随机选取3-5个视野拍照,每只动物共拍摄30张照片。 1.3运用体视学方法分别计算出大鼠大脑皮质总体积、皮质体积皱缩率、皮质内毛细血管长度密度和总长度、体积密度和总体积、表面积密度和总表面积。 2结果 2.1青年组、老年组雌性大鼠皮质由于组织处理引起的体积皱缩率分别是53.9±7.3%及48.8±8.8%。青年组大鼠大脑组织处理前皮质总体积为457.5±37.0 mm~3,老年组大鼠大脑组织处理前皮质总体积为426.3±63.6 mm3,两组之间无显著性差异(p0.05)。 2.2青年组大鼠皮质毛细血管的总长度为331.9±62.2 m,老年组大鼠皮质毛细血管的总长度为281.6±61.5 m。两组大鼠皮质毛细血管的总长度无显著性差异(p 0.05)。 2.3青年组大鼠皮质毛细血管的总体积为6.7±1.2 mm3,老年组大鼠皮质毛细血管的总体积为6.0±1.2 mm3。两组大鼠皮质毛细血管的总体积无显著性差异(p 0.05)。 2.4青年组大鼠皮质毛细血管的总表面积为46.5±9.8 cm2,老年组大鼠皮质毛细血管的总表面积为41.7±9.4 cm2。两组大鼠皮质毛细血管的总表面积无显著性差异(p 0.05)。第二部分大鼠大脑白质毛细血管老年性改变的体视学研究 1材料与方法 1.1雌性Long-Evans大鼠,青年组(7月龄)10只,老年组(27月龄)10只。 1.2将大鼠麻醉灌注固定后,从每只大鼠随机抽取一侧大脑半球,制作2 mm厚的连续脑组织块,从每个脑块切取一张4μm厚的各向同性切片,进行免疫组化染色。在100倍油镜下拍每张切片的整个白质区域,拍得4-6个视野,每只动物共拍摄30张照片。 1.3运用体视学方法分别计算出大鼠大脑白质总体积、白质体积皱缩率、白质内毛细血管长度密度和总长度、体积密度和总体积、表面积密度和总表面积。 2结果 2.1青年组、老年组雌性大鼠白质由于组织处理引起的体积皱缩率分别是46.4±8.8%及46.1±7.3%。青年组大鼠大脑组织处理前白质总体积为91.7±12.1 mm~3,老年组大鼠大脑组织处理前白质总体积为78.0±16.4 mm~3,老年组比青年组显著降低了14.9%(p 0.05)。 2.2青年组大鼠白质毛细血管的总长度为34.4±7.8 m,老年组大鼠白质毛细血管的总长度为23.3±5.1 m。老年组比青年组显著降低了32.2%(p 0.01)。 2.3青年组大鼠白质毛细血管的总体积为0.81±0.13 mm~3,老年组大鼠白质毛细血管的总体积为0.54±0.14 mm~3。老年组比青年组显著降低了33.2%(p 0.01)。 2.4青年组大鼠白质毛细血管的总表面积为5.6±1.0 cm2,老年组大鼠白质毛细血管的总表面积为3.8±0.89 cm2。老年组比青年组显著降低了31.7%(p 0.01)。全文结论 1.本研究首次把新的体视学方法和免疫组化技术结合起来定量研究大鼠大脑皮质毛细血管、白质毛细血管的老年性改变。 2.大鼠大脑皮质毛细血管总长度、总体积及总表面积不存在显著的老年性改变。 3.老年大鼠白质毛细血管总长度、总体积及总表面积显著降低。 4.首次获得了青年及老年雌性大鼠大脑皮质毛细血管及白质毛细血管的总长度、总体积及总表面积的基本数值,这些数值为今后运用该动物模型探讨中枢神经系统退化性疾病对皮质、白质内毛细血管的影响提供了重要的参考数据。
[Abstract]:The prevalence of memory and cognitive decline in the elderly. The mechanism that leads to the memory of the old brain and the decline of cognitive function is multi-faceted. Among them, vascular factors may be one of the important mechanisms to cause brain function decline in old age. the brain capillary is a three-dimensional network structure which is matched with the smallest branches of the cerebral vascular tree and plays an important role in regulating the microenvironment of the brain, maintaining local cerebral blood flow, and normal functional activity of neurons in the microenvironment surrounding the capillary, The effective transmission of nerve impulse depends on the morphological structure of capillary vessel. The changes of capillary morphology in different parts of the brain, such as capillary distortion, spherical change and line-like change, were observed in a large number of qualitative researches, and the ultrastructural changes of endothelial cell atrophy, thickening of basement membrane and degeneration of foot cells were observed. However, the quantitative study on the capillaries of the brain is less and is not limited to cerebral cortex, hippocampus and so on. In recent years, it has been found that there is no significant cerebral cortex neuron death in the normal old brain using the new method of stereology. So, do cortical capillaries have age-related changes? Although there are studies in this field, the results of these studies are quite different and do not carry out the principle of modern stereology. In addition, the study of the method of stereology showed that the white matter volume in the elderly decreased significantly, and the total length of myelinated nerve fibers in white matter decreased significantly. At this point, white matter capillaries have changed? No reports have been reported at home and abroad. Therefore, on the basis of the summary of the deficiency of the research on the senile changes of the capillary capillary in the past and the supplement to the white matter capillary age, this experiment takes rat as animal model, uses the stereological quantitative research method and the immunohistochemical technique to the cerebral cortex, Age-related changes of capillary in white matter are studied. Changes of capillaries in cerebral cortex of rat cerebral cortex in the first part visual study Materials and Methods 1. 1 female Long-Evans rat, young group (7 months old) 10, old Ten rabbits (27 months old) were randomly extracted one side of cerebral hemisphere from each rat, and a 2 mm thick continuous brain tissue mass was randomly extracted from each rat, and a 4. m u.m thickness was cut from each brain block. Isotropic slices were stained with immunohistochemical staining. 3-5 fields of vision were randomly selected from each slice cortex region under 100-fold oil mirror The total volume of cerebral cortex, volume shrinkage of cortex, length density and total length of capillary in cortex were calculated by stereological method. bulk density degree and total volume, surface area density, and total surface area. Results 2. 1 young group, the cortex of female rats in the old group was caused by tissue treatment. The volume shrinkage rate was 53. 9% 7. 3% and 48. 8% 8. 8% respectively. The total volume of cortex before treatment of cerebral tissue in young rats was 457. 5 mm37. 0 mm ~ 3, and the total volume of cortex before brain tissue treatment in the aged rats was 426. The total length of cortex capillary in the aged rats was 331. 9/ 62. 2 m, and the total length of capillary capillary in the aged rats was 281. 6 mm61. There was no significant difference in the total length of cortex capillaries in the two groups (p 0.05). The total volume of capillary capillary in the aged rats was 6. 0. 2 mm3. There was no significant difference in the total volume of cortex capillaries in the two groups (p 0.05). The total surface area of the cortical capillaries in the young rats was 4. 6.5 The total surface area of the cortex capillaries in the aged rats was 4. 8 cm2 and 9. 8 cm2. 1. 7 B9. 4 cm2. Total surface of the cortical capillaries of the two sets of rats No significant difference in product Stereological study of age-related changes in cerebral white matter capillary in the second part of rats (p 0.05) Materials and Methods 1. 1 female Long-Evans rats, 10 young adults (7 months old), 10 elderly (27 months old) group (27 months old). Rats were randomly drawn from one side of the brain hemisphere to create a 2 mm thick continuous brain tissue block from each brain block with a 4. m u.m thick each. the whole white matter area of each slice is photographed under 100 times of oil mirror, 4-6 fields of vision are taken, 30 photos are taken for every animal, The method The total volume of white matter, the volume shrinkage of white matter, the length density and total length, volume density and total volume, surface area density and total volume of white matter in the white matter were calculated. Results 2. Results The volume shrinkage of white matter caused by tissue treatment was 46. 4% 8. 8% and 46. 1% 7. 3%, respectively. The total white matter volume was 91% in young rats. The total volume of white matter before brain tissue treatment in aged group was 78. 0 65.16. 4 mm ~ 3. The old group was significantly lower than that of young group by 14.9% (p 0.05). The total length of white matter capillary was 34. 4, 7. 8 m, and the total length of white matter capillary in the old group was 23. 3/ 5. 1m. The old age group was significantly lower than that of the young group.% (p 0.01). 2. 3 youth group white matter capillary The total volume of blood vessels was 0. 81, 0. 13 mm ~ 3, and the total volume of white matter capillary in the aged rats was 0. 54% 0. 14 mm ~ 3. The old age group was significantly higher than the young group. a decrease of 30.2% (p 0.01). 2. 4 young people Group rat white The total surface area of the capillary was 5. 6 cm 1. 0 cm2, and the total surface area of white matter capillary in the old group was 3. 8 mm0. 89 cm2. 31 7% (p 0.01) were significantly lower than that in the young group (p 0.01). For the first time in this study, the new method of stereology and immunohistochemical technique were combined in quantitative study. Age-related changes in capillary and white matter capillaries in the cerebral cortex of rats. The total length, total volume and total surface area of capillaries in the cerebral cortex of rats did not have significant age-related changes. 3. The total length of white matter capillary in the aged rats the total volume and the total surface area were significantly reduced.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：R322

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