大鼠大脑白质及其有髓神经纤维的体视学研究

发布时间：2018-01-05 03:25

本文关键词：大鼠大脑白质及其有髓神经纤维的体视学研究　出处：《重庆医科大学》2007年硕士论文　论文类型：学位论文

【摘要】： 目的关于老年大脑的结构改变,几十年来一直认为是由于大脑皮质神经元的大量死亡造成的。但是丹麦科学家运用新的体视学方法进行的定量研究发现正常老年大脑不存在显著性大脑皮质神经元死亡,而其白质体积存在显著性改变。我们在国际上首次报道了老年人大脑白质的有髓神经纤维总长度显著性下降。虽然我们作了一些努力排除具有老年痴呆的病例,但是,要排除早期老年性痴呆病例并不是一件非常容易的事。由于国际上公认大鼠不会患老年痴呆,因此为了排除早期老年性痴呆病例对正常大脑老年改变研究的影响,本实验采用Long-Evans大鼠作为实验动物,将透射电子显微镜技术与新的体视学方法结合起来继续探讨了大脑白质及其内有髓神经纤维的老年性改变。第一部分 1材料与方法 1.1 6～8月龄Long-Evans大鼠,雌雄各5只。 1.2从每只大鼠随机抽取一侧大脑半球,再从中随机抽取4块白质组织块作成超薄切片,从每张切片上随机抽取16个视野在透射电镜下放大6000倍拍照。 1.3运用体视学方法分别计算出雌雄组大鼠大脑白质体积、白质内有髓神经纤维长度密度和总长度、有髓神经纤维平均直径、白质内有髓神经纤维体积密度和总体积、髓鞘体积密度和总体积。 2结果 2.1雌性大鼠大脑白质总体积为119.57±7.52 mm3,雄性大鼠大脑白质总体积为173.22±21.03 mm3,两组之间的差异为44.9% (P0.05)。 2.2雌性大鼠白质内有髓神经纤维总长度为129.26±28.78 km,雄性大鼠白质内有髓神经纤维总长度为190.79±73.49 km,两组之间的差异为47.7% (P0.05),但是不具有统计学意义。 2.3雌性大鼠白质内有髓神经纤维平均直径为0.56±0.03μm,雄性大鼠白质内有髓神经纤维总长度为0.53±0.04μm,相差4.3% (P0.05),没有显著性。 2.4雌性大鼠白质内有髓神经纤维的总体积为58.13±9.34 mm3,雄性大鼠白质内有髓神经纤维的总体积为80.66±10.15 mm3,差异为38.7% (P 0.01)。 2.5雌性大鼠白质内有髓神经纤维髓鞘的总体积为26.83±3.62 mm3,雄性大鼠白质内有髓神经纤维髓鞘的总体积为36.92±6.62 mm3,差异为37.6% (P 0.01)。第二部分 1材料与方法 1.1 6～8月龄Long-Evans大鼠,雌雄各5只。18月龄Long-Evans大鼠,雌性5只,雄性4只。 1.2从每只大鼠随机抽取一侧大脑半球,再从中随机抽取4块白质组织块作成超薄切片,从每张切片上随机抽取16个视野在透射电镜下放大6000倍拍照。 1.3运用体视学方法分别计算出年青组和老年组大鼠大脑白质总体积、白质内有髓神经纤维长度密度和总长度、有髓神经纤维平均直径、白质内有髓神经纤维体积密度和总体积、髓鞘体积密度和总体积。 2结果 2.1大鼠大脑白质体积、白质内有髓神经纤维总长度分别从年青组的133.34±20.79 mm3和160.02±61.81 km下降到了老年组的101.14±13.73 mm3和94.43±47.75 km,下降率分别为24.1% (P0.01)和41% (P0.05)。老年组大鼠有髓神经纤维体积密度、髓鞘体积密度和纤维平均直径分别增加了30% (P0.01)、23.9% (P0.05)和31% (P0.01)。而老年大鼠有髓神经纤维长度密度、有髓神经纤维总体积和髓鞘总体积虽有所下降,但均无统计学意义。 2.2老年组18月龄雌性大鼠大脑白质体积、有髓神经纤维长度密度和总长度的降低没有显著性。有髓神经纤维体积密度、有髓神经纤维总体积、髓鞘体积密度、髓鞘总体积和有髓神经纤维平均直径均有显著性的增加,增加率分别为41.7% (P0.01)、29.7% (P0.01)、42.6% (P0.05)、30.0% (P0.05)、21.6% (P0.05)。 2.3老年组18月龄雄性大鼠大脑白质体积、有髓神经纤维总长度、有髓神经纤维总体积和髓鞘的总体积分别显著降低了38.8% (P0.01)、66.8% (P0.05)、38.1% (P0.01)和35.2% (P0.05);有髓神经纤维直径显著性增加了42.6% (P0.01)。而有髓神经纤维长度密度、有髓神经纤维体积密度和髓鞘体积密度的改变没有显著性。全文结论 1.本研究在国际上首次把新的体视学方法和电子显微镜技术结合起来定量研究大鼠大脑白质及其有髓神经纤维的性别差异和老年改变。 2.首次发现成年雌雄性Long-Evans大鼠大脑白质总体积、有髓神经纤维总体积和髓鞘的总体积之间均存在性别二相性。 3.证实了以前在人大脑白质的研究发现,即存在老年性大脑白质萎缩,白质萎缩主要是由于白质内细小直径的有髓神经纤维总长度下降引起的。 4.首次发现大脑白质的老年改变存在性别差异,雄性大鼠大脑白质的萎缩和有髓神经纤维总长度的下降要明显早于雌性动物。 5.首次获得了雄性和雌性大鼠大脑白质体积、白质内有髓神经纤维的总长度和总体积及纤维平均直径的基本数值,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大脑白质有髓神经纤维的影响提供了重要的参考数据
[Abstract]:Change of aged brain, for decades has been considered to be due to the massive death of neurons in the cerebral cortex caused. But the quantitative study of Danish scientists using the new stereological methods were found in normal aged brain no significant death of the neurons in the cortex, and the white matter volume was significantly changed. We in the world first reported the elderly cerebral white matter, the total length of the myelinated nerve fibers decreased significantly. Although we have made some efforts have excluded dementia cases, however, to the exclusion of early Alzheimer's disease is not a very easy thing. Because of the internationally recognized rats don't suffer from Alzheimer's disease, in order to exclude in early Alzheimer's disease cases the effect of the changes of normal brain aging, this experiment using Long-Evans rats as experimental animal, the transmission electron microscopy Combined with new stereological methods, mirror technology continues to explore the age-related changes in white matter and its intramedullary nerve fibers in the brain.
Part one
1 materials and methods
1.16 to 8 month old Long-Evans rats, 5 male and female.
1.2 randomly selected one hemisphere from each rat, and then randomly selected 4 white matter tissue blocks to make ultrathin slices. 16 slices of vision were randomly selected from each slice, magnified 6000 times under transmission electron microscope.
1.3 stereological method was used to calculate the volume of white matter, the length and total length of myelinated nerve fibers in white and male rats, the average diameter of myelinated nerve fibers, the volume density and total volume of myelinated nerve fibers in white matter, the volume density and total volume of myelin sheath.
2 Results
The total volume of white matter in the brain of 2.1 female rats was 119.57 + 7.52 mm3, the total volume of white matter in the male rats was 173.22 + 21.03 mm3, and the difference between the two groups was 44.9% (P0.05).
2.2, the total length of myelinated nerve fibers in white matter of female rats is 129.26 + 28.78 km. The total length of myelinated nerve fibers in male rats is 190.79 + 73.49 km, and the difference between two groups is 47.7% (P0.05), but not statistically significant.
2.3 the average diameter of myelinated nerve fibers in white matter of female rats is 0.56 + 0.03 m. The total length of myelinated nerve fibers in male rats is 0.53 + 0.04 m, and the difference is 4.3% (P0.05), with no significant difference.
2.4 the total volume of myelinated nerve fibers in white matter of female rats was 58.13 + 9.34 mm3, and the total volume of myelinated nerve fibers in male rats was 80.66 + 10.15 mm3, with a difference of 38.7% (P 0.01).
2.5 the total volume of myelinated nerve fibers in the white matter of female rats was 26.83 + 3.62 mm3, and the total volume of myelinated nerve fibers in the white matter of male rats was 36.92 + 6.62 mm3, with a difference of 37.6% (P 0.01).
The second part
1 materials and methods
1.16 to 8 month old Long-Evans rats, 5.18 month old Long-Evans rats, 5 females and 4 males.
1.2 randomly selected one hemisphere from each rat, and then randomly selected 4 white matter tissue blocks to make ultrathin slices. 16 slices of vision were randomly selected from each slice, magnified 6000 times under transmission electron microscope.
1.3 use stered calculated total volume of young and old rats brain white matter methodology, myelinated fibers in the white matter of the length density and total length, the mean diameter of the myelinated fibers, the myelinated fibers in the white matter volume density and total volume of myelin, volume density and total volume.
2 Results
The 2.1 volume of cerebral white matter in rats, the white matter in the total length of the myelinated nerve fibers from the young group of 133.34 + 20.79 and 160.02 + 61.81 mm3 km down to the elderly group of 101.14 + 13.73 + 47.75 mm3 and 94.43 km, the decreasing rate were 24.1% (P0.01) and 41% (P0.05) in elderly group. Rat myelinated nerve fiber volume density, average diameter and volume density of myelin fibers were increased by 30% (P0.01), 23.9% (P0.05) and 31% (P0.01). The old rats myelinated fiber length density, the total volume of the total volume of the myelinated fibers and myelin has decreased, but there was no statistical significance.
The 2.2 group of 18 month old elderly female rat brain white matter volume, reduce the myelinated fiber length density and total length was not significant. The myelinated nerve fiber volume density, the total volume of the myelinated nerve fibers and myelin volume density, the total volume of myelin and increased the mean diameter of the myelinated fibers were significantly increased, the rate of were 41.7% (P0.01), 29.7% (P0.01), 42.6% (P0.05), 30% (P0.05), 21.6% (P0.05).
2.3 of the elderly group of 18 month old male rat brain white matter volume, the total length of the myelinated fibers, the total volume of the total volume of the myelinated fibers and the myelin sheath were significantly decreased by 38.8% (P0.01), 66.8% (P0.05), 38.1% (P0.01) and 35.2% (P0.05); myelinated nerve fiber diameter significantly an increase of 42.6% (P0.01). The myelinated fiber length density, volume density of myelinated nerve fibers and myelin volume density change was not significant.
Full text conclusion
1., for the first time in the world, the new stereology method and electron microscopy technology were applied in the world to quantitatively study gender differences and elderly changes in white matter and myelinated nerve fibers of rats.
2. we found that adult male and female Long-Evans rats of cerebral white matter volume, there are gender dimorphism between the total volume of the total volume of the myelinated fibers and the myelin sheath.
3., it is confirmed that previous studies in the white matter of the NPC showed that there existed aging brain white matter atrophy and white matter atrophy, mainly due to the decrease of the total length of the small diameter myelinated nerve fibers in the white matter.
4., for the first time, there were gender differences in the aging of white matter in the brain. The atrophy of white matter and the total length of myelinated nerve fibers in male rats were significantly lower than those in females.
5. for male and female rats brain white matter volume, white matter within the basic numerical average diameter of the total length of the myelinated nerve fibers and the total volume and fiber, these values for the future use of the animal model of central nervous system degenerative diseases of myelinated fibers influence provide important reference data to the brain white matter

【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2007
【分类号】：R329.54

【相似文献】