大鼠胼胝体中段和压部体积及有髓神经纤维老年性改变的体视学研究
发布时间：2018-08-09 14:55
【摘要】：1前言 人类胼胝体是连接大脑两侧半球最大的白质连合。随着年龄增加,胼胝体前部会明显减少,嘴和膝比压部的比例下降,干部和压部的厚度变薄,胼胝体的前后长度和最大高度增高。胼胝体内包含有髓神经纤维和无髓神经纤维,胼胝体的大小由纤维的数量和直径的大小决定。衰老是否引起了胼胝体神经纤维直径的改变呢?目前的研究主要集中在出生前和出生后240天以内,但对于成年后一直到老年时期的胼胝体超微形态学的研究较少。有研究表明胼胝体接受来自颞叶后部包括颞极和颞上、下回的纤维,胼胝体干部的后部和压部接受颞-顶-枕的连接区域以及顶上小叶和枕叶皮质的纤维,胼胝体的干部和压部可能与颞皮质及颞皮质相关的感觉功能有关;听区位于颞上回,听力的不对称性与胼胝体的大小,尤其胼胝体前部和后部的大小呈明显的负相关。所以胼胝体的干部和压部与颞皮质相联系,并与感觉功能相关。为了解老化对于胼胝体中段和压部的影响,本研究将应用新的体视学方法和电子显微镜技术来测定胼胝体中段(anterriormidbody,posterior midbody and isthmus)和压部体积及其内有髓神经纤维的老年改变。 2目的 运用新的体视学方法定量研究成年、中老年和老年雌性Long-Evans大鼠胼胝体中段和压部的体积、有髓神经纤维的长度密度、总长度、有髓神经纤维的直径、有髓神经纤维体积、髓鞘体积、髓鞘厚度、髓鞘的内周长、外周长的老年改变。 3方法 选择成年组(7月龄,250±20 g)、中老年组(18月龄,350±25 g)和老年组(27月龄,380±40 g)雌性Long-Evans大鼠各5只。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。以Witelson(1989)的工作为基础,将胼胝体分为三部分,前5/15为前部(包括Rostrum,Genu and Rostral Body),后3/15为后部(包括Splenium),中间剩下的部分为中段(包括Anterior Midbody,Posterior Midbody and Isthmus)。制作1 mm厚的连续脑组织块。常规电镜标本制备。在放大14400倍的透射电子显微镜下,随机选取视野进行拍照,每个组织块拍摄5～6张电镜照片,因此每只大鼠胼胝体中段和压部各得到10～12张电镜照片。运用新的体视学方法定量研究成年、中老年和老年雌性Long-Evans大鼠胼胝体中段和压部的体积、有髓神经纤维的长度密度、总长度、有髓神经纤维的直径、有髓神经纤维体积、髓鞘体积、髓鞘厚度、髓鞘的内周长、外周长的老年改变。 4结果 4.1老年组大鼠的胼胝体中段体积较成年组下降21.5%(p0.05),老年组较中老年组下降18.1%(p0.01)。压部体积未见明显老年性改变(p0.05)。 4.2老年组胼胝体中段有髓神经纤维总长度较成年组和中老年组分别降低28.8%和27.7%,但差异没有统计学意义(p0.05)。胼胝体压部有髓神经纤维总长度也未见明显老年性改变(p0.05)。 4.3 3个年龄组之间,胼胝体中段和压部内的有髓神经纤维平均直径均不存在显著差异。 4.4在胼胝体中段,直径为0.3～0.9μm的有髓神经纤维的总长度在老年组比成年组和中老年组有所降低,其中直径为0.7～0.8μm的有髓神经纤维的总长度在老年组(3.152 km)比成年组(6.602 km)降低52.3%(p0.05),其他直径段有髓神经纤维长度的变化没有统计学意义;直径为1.5～1.6μm的有髓神经纤维的总长度在老年组(0.614 km)比成年组(0.114 km)增加4.55倍(p0.05)。在胼胝体压部,直径为0.4～0.7μm的有髓神经纤维总长度在老年组比成年组和中老年组有所增加,但差异没有统计学意义;直径为1.2～1.3μm的有髓神经纤维总长度在老年组(0.189 km)比成年组(0.066 km)和中老年组(0.074 km)分别增加1.86倍(p0.05)和1.55倍(p0.05);直径为1.4～1.5μm的有髓神经纤维的总长度在老年组(0.113 km)比成年组(0.005 km)增加21.6倍(p0.05)。 4.5胼胝体中段的有髓神经纤维的体积,在年轻组为27.84±1.29mm~3;在中老年组为29.09±1.39 mm~3;老年组为20.12±1.41 mm~3。中段内老年组有髓神经纤维的体积明显比成年组和中老年组小(p0.05)。而胼胝体压部的有髓神经纤维的体积没有明显的老年改变。中段内有髓神经纤维的体积与胼胝体中段体积存在正相关(r = 0.869, p0.01),压部内有髓神经纤维的体积与胼胝体压部体积存在正相关(r = 0.931, p0.01)。 4.6中段内老年组有髓神经纤维的髓鞘体积明显低于成年组和中老年组(p0.01)。压部内有髓神经纤维的髓鞘体积没有明显老年性改变。 4.7胼胝体中段和压部内有髓神经纤维的直径,轴突直径和髓鞘厚度的平均值均无明显的老年改变。根据不同的有髓神经纤维直径,对有髓神经纤维进行分段,不同直径段的髓鞘厚度存在明显老年改变。直径相对较大的有髓神经纤维的髓鞘厚度随着年龄的增加而增加。在胼胝体中段,直径为0.9～1.0μm和1.2～1.3μm的有髓神经纤维的髓鞘厚度在中老年组比成年组均显著增加(p0.01,p0.05);直径为1.5～1.6μm的有髓神经纤维的髓鞘厚度在中老年组比成年组小(p0.05),老年组比中老年组小(p0.05)。在胼胝体压部,直径为0.9～1.0μm和1.1～1.2μm的有髓神经纤维的髓鞘厚度在老年组比成年组显著增加(p0.05)。 4.8胼胝体中段与压部的外周长与内周长之差,以及两者之间的比值的平均值均无显著的老年改变。在胼胝体中段,当与成年组比较时,直径大于0.9μm的多个直径段的有髓神经纤维的髓鞘外、内周长之差在老年组和中老年组均增加;当与成年组比较时,直径大于0.9μm的多个直径段的有髓神经纤维的髓鞘外、内周长的比值在老年组和中老年组均增加。髓鞘外、内周长之差和之比的改变均表明,在中段内直径相对较大的有髓神经纤维的髓鞘随年龄的增加而变厚。在胼胝体压部,髓鞘外、内周长之差和之比的改变均表明,在中段内直径相对较大的有髓神经纤维的髓鞘随年龄的增加而变厚。 5结论 5.1本研究显示老年大脑胼胝体压部体积没有发生显著性改变,老年大脑胼胝体中段体积显著性下降。 5.2胼胝体中段内小直径的有髓神经纤维总长度显著性降低可能是老年胼胝体中段体积显著性下降的重要原因之一。 5.3胼胝体压部较大直径有髓神经纤维长度随年龄增加而增加。 5.4胼胝体中段和压部内较大直径有髓神经纤维髓鞘厚度随年龄增加而增加,而较小直径有髓神经纤维髓鞘厚度变化不明显。
[Abstract]:1 Preface
The corpus callosum is the largest white matter connected to the two hemispheres of the brain. As the age increases, the anterior part of the corpus callosum decreases obviously, the ratio of the mouth to the knee is reduced, the thickness of the cadres and the pressure part is thinner, the length and maximum height of the corpus callosum increases. The corpus callosum contains myelinated and unmyelinated nerve fibers, and the corpus callosum is large. The size of the fibers depends on the size and size of the fibers. Does senescence cause changes in the diameter of the corpus callosum fibers? The current study is mainly focused on the 240 days before and after birth, but there are few studies on the ultrastructure of the corpus callosum in the adult period. The branches of the temporomandibular and inferior temporal and inferior gyrus, the posterior part of the corpus callosum and the pressure part of the corpus callosum accepted the junction of the temporo top occipital and the upper lobule and the occipital cortex. The corpus callosum may be associated with the sensory function of the temporal cortex and the temporal cortex; the auditory area is located in the upper temporal gyrus, the asymmetry of hearing and the size of the corpus callosum. In particular, the anterior and posterior portion of the corpus callosum is negatively correlated with the size of the posterior part of the corpus callosum. Therefore, the corpus callosum is associated with the temporal cortex and is associated with the sensory function. In order to understand the effect of aging on the middle segment and pressure of the corpus callosum, a new stereological method and a microscopical technique will be used to determine the median corpus callosum (anterriormidbod Y, posterior midbody and isthmus) and compression volume and the changes of myelinated nerve fibers in the aged.
2 purposes
A new stereological method was used to quantify the volume of the middle and pressure parts of the corpus callosum in adult, middle-aged and old female Long-Evans rats, with the length density of the myelinated nerve fibers, the total length, the diameter of the myelinated nerve fibers, the volume of myelinated nerve fibers, the volume of myelin sheath, the thickness of myelin sheath, the inner circumference of medullary sheath, and the external circumference of the elderly.
3 method
The adult group (7 month old, 250 + 20 g), the middle and old age group (18 month old, 350 + 25 g) and the old group (27 month old, 380 + 40 g) of the female Long-Evans rats each. After the rats were instilled, the rats were randomly selected from each rat. The corpus callosum was divided into three part with Witelson (1989) working as the basis, and the front 5/15 was the front part (including Rostru). M, Genu and Rostral Body), after 3/15 as the back part (including Splenium), the remaining part of the middle part is the middle section (including Anterior Midbody, Posterior Midbody and). Making 1 thick continuous brain tissue blocks. Preparation of conventional electron microscopy specimens. Under the amplification of 14400 times the transmission electron microscope, random selection of visual field is taken to take pictures, each tissue block is taken. 5~6 electron microscopic photographs were taken, and 10~12 electron microscopic photographs were taken in each rat's corpus callosum and the pressure part. A new stereological method was used to quantify the volume of the middle and pressure parts of the corpus callosum of adult, middle-aged and old female Long-Evans rats, with the length of the myelinated nerve fiber, the total length, the diameter of the myelinated nerve fibers, and the medullary God. The age-related changes of myelin sheath volume, myelin sheath volume, myelin sheath thickness, myelin sheath inner perimeter and peripheral length were observed.
4 Results
4.1 the volume of the corpus callosum in the aged group was 21.5% lower than that in the adult group (P0.05), and that in the elderly group was 18.1% (P0.01) compared with the middle aged group (P0.05).
4.2 the total length of the medullary nerve fibers in the middle segment of the corpus callosum in the elderly group was 28.8% and 27.7% lower than that in the adult and middle age groups, but the difference was not statistically significant (P0.05). The total length of the myelinated nerve fibers in the corpus callosum was not significantly changed (P0.05).
4.3 There was no significant difference in the average diameter of myelinated nerve fibers between the three age groups.
4.4 in the middle segment of the corpus callosum, the total length of the myelinated nerve fibers with a diameter of 0.3 to 0.9 m decreased in the elderly group than in the adult and middle aged groups. The total length of the myelinated nerve fibers with a diameter of 0.7 to 0.8 micron m decreased by 52.3% (6.602 km) in the elderly group (6.602 km), and the length of the myelinated nerve fibers in the other diameter segments was changed. The total length of myelinated nerve fibers with a diameter of 1.5 ~ 1.6 mu m increased by 4.55 times (P0.05) in the elderly group (0.614 km) than in the adult group (0.114 km). In the corpus callosum, the total length of the myelinated nerve fibers with a diameter of 0.4 to 0.7 um m increased in the elderly group than in the adult and middle aged groups, but the difference was not statistically significant; The total length of myelinated fibers with a diameter of 1.2 to 1.3 m (0.189 km) increased 1.86 times (P0.05) and 1.55 times (P0.05) in the elderly group (0.066 km) and in the middle and old age group (0.074 km), and the total length of the myelinated fibers with the diameter of 1.4 to 1.5 mu (0.113 km) increased by 21.6 times (P0.05) in the elderly group (0.113 km) than in the adult group (0.005 km).
4.5 the volume of myelinated nerve fibers in the middle segment of the corpus callosum was 27.84 + 1.29mm~3 in the young group and 29.09 + 1.39 mm~3 in the middle and old age group; the volume of myelinated nerve fibers in the elderly group was 20.12 + 1.41 mm~3.. The volume of myelinated nerve fibers was significantly smaller than that in the adult and middle aged groups (P0.05). There was a positive correlation between the volume of medullary nerve fibers in the middle segment and the volume of the corpus callosum (r = 0.869, P0.01). There was a positive correlation between the volume of myelinated nerve fibers in the pressure part and the volume of the corpus callosum (r = 0.931, P0.01).
4.6 the medullary sheath volume of the myelinated nerve fibers in the elderly group was significantly lower than that in the adult group and the middle aged group (P0.01). The myelin sheath volume of the myelinated nerve fibers in the press did not change significantly.
4.7 the diameter of the myelinated nerve fibers, the diameter of the axon and the thickness of the myelin sheath in the middle part of the corpus callosum and the average value of the medullary sheath thickness were no obvious old changes. According to the diameter of the myelinated nerve fibers, the myelinated fibers were segmented and the myelin thickness in different diameter segments had obvious aging changes. The pulp of the myelinated nerve fibers with relatively large diameter was the pulp. The thickness of the sheath increased with age. The myelin thickness of the myelinated nerve fibers in the middle and old age groups increased significantly (P0.01, P0.05) in the middle of the corpus callosum and in the middle-aged and old age groups. The myelin thickness of the myelinated nerve fibers with the diameter of 1.5 ~ 1.6 m in the middle and old age group was smaller than that of the adult group (P0.05), and the older group was compared with the middle age group (P0.01, P0.05). In the elderly group (P0.05), the myelin thickness of myelinated nerve fibers in the aged group increased significantly (P0.05) at the corpus callosum pressure, with the medullary sheath thickness of the myelinated nerve fibers with the diameter of 0.9 to 1 mu and 1.1 ~ 1.2 mu m.
4.8 the difference between the outer circumference and the internal circumference of the middle corpus callosum and the pressure part, and the average value of the ratio between the two groups were not significantly changed. In the middle of the corpus callosum, the difference in the length of the circumferential length increased in the elderly and the middle aged and old groups when compared with the adult group, and the myelinated nerve fibers with the diameter more than 0.9 m in diameter were increased. In the adult group, the myelin sheath of the myelinated nerve fibers with a diameter greater than 0.9 m in diameter increased the ratio of the inner circumference in both the elderly and the middle and old groups. The difference in the length of the medullary and the change of the ratio of the intramedullary sheath to the medullary sheath thickened with the increase of age. The change of the ratio of the difference of the inner circumference and the outer circumference of the compression part and the outer part of the myelin sheath showed that the myelin sheath of the myelinated nerve fibers with relatively large diameter in the middle part thickened with the increase of age.
5 Conclusion
5.1 This study showed that there was no significant change in the pressure volume of the corpus callosum in the aged, and the middle volume of the corpus callosum decreased significantly in the aged.
5.2 A significant decrease in the total length of small-diameter myelinated nerve fibers in the middle part of the corpus callosum may be one of the important reasons for the significant decrease in the volume of the middle part of the corpus callosum in the elderly.
5.3 The length of the larger diameter myelinated nerve fibers in the corpus callosum increased with age.
5.4 the medullary sheath thickness of the medullary nerve fibers in the middle and pressure parts of the corpus callosum increased with age, but the thickness of the myelinated myelin sheath in the smaller diameter was not obvious.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：R322.81
本文编号：2174447
[Abstract]:1 Preface
The corpus callosum is the largest white matter connected to the two hemispheres of the brain. As the age increases, the anterior part of the corpus callosum decreases obviously, the ratio of the mouth to the knee is reduced, the thickness of the cadres and the pressure part is thinner, the length and maximum height of the corpus callosum increases. The corpus callosum contains myelinated and unmyelinated nerve fibers, and the corpus callosum is large. The size of the fibers depends on the size and size of the fibers. Does senescence cause changes in the diameter of the corpus callosum fibers? The current study is mainly focused on the 240 days before and after birth, but there are few studies on the ultrastructure of the corpus callosum in the adult period. The branches of the temporomandibular and inferior temporal and inferior gyrus, the posterior part of the corpus callosum and the pressure part of the corpus callosum accepted the junction of the temporo top occipital and the upper lobule and the occipital cortex. The corpus callosum may be associated with the sensory function of the temporal cortex and the temporal cortex; the auditory area is located in the upper temporal gyrus, the asymmetry of hearing and the size of the corpus callosum. In particular, the anterior and posterior portion of the corpus callosum is negatively correlated with the size of the posterior part of the corpus callosum. Therefore, the corpus callosum is associated with the temporal cortex and is associated with the sensory function. In order to understand the effect of aging on the middle segment and pressure of the corpus callosum, a new stereological method and a microscopical technique will be used to determine the median corpus callosum (anterriormidbod Y, posterior midbody and isthmus) and compression volume and the changes of myelinated nerve fibers in the aged.
2 purposes
A new stereological method was used to quantify the volume of the middle and pressure parts of the corpus callosum in adult, middle-aged and old female Long-Evans rats, with the length density of the myelinated nerve fibers, the total length, the diameter of the myelinated nerve fibers, the volume of myelinated nerve fibers, the volume of myelin sheath, the thickness of myelin sheath, the inner circumference of medullary sheath, and the external circumference of the elderly.
3 method
The adult group (7 month old, 250 + 20 g), the middle and old age group (18 month old, 350 + 25 g) and the old group (27 month old, 380 + 40 g) of the female Long-Evans rats each. After the rats were instilled, the rats were randomly selected from each rat. The corpus callosum was divided into three part with Witelson (1989) working as the basis, and the front 5/15 was the front part (including Rostru). M, Genu and Rostral Body), after 3/15 as the back part (including Splenium), the remaining part of the middle part is the middle section (including Anterior Midbody, Posterior Midbody and). Making 1 thick continuous brain tissue blocks. Preparation of conventional electron microscopy specimens. Under the amplification of 14400 times the transmission electron microscope, random selection of visual field is taken to take pictures, each tissue block is taken. 5~6 electron microscopic photographs were taken, and 10~12 electron microscopic photographs were taken in each rat's corpus callosum and the pressure part. A new stereological method was used to quantify the volume of the middle and pressure parts of the corpus callosum of adult, middle-aged and old female Long-Evans rats, with the length of the myelinated nerve fiber, the total length, the diameter of the myelinated nerve fibers, and the medullary God. The age-related changes of myelin sheath volume, myelin sheath volume, myelin sheath thickness, myelin sheath inner perimeter and peripheral length were observed.
4 Results
4.1 the volume of the corpus callosum in the aged group was 21.5% lower than that in the adult group (P0.05), and that in the elderly group was 18.1% (P0.01) compared with the middle aged group (P0.05).
4.2 the total length of the medullary nerve fibers in the middle segment of the corpus callosum in the elderly group was 28.8% and 27.7% lower than that in the adult and middle age groups, but the difference was not statistically significant (P0.05). The total length of the myelinated nerve fibers in the corpus callosum was not significantly changed (P0.05).
4.3 There was no significant difference in the average diameter of myelinated nerve fibers between the three age groups.
4.4 in the middle segment of the corpus callosum, the total length of the myelinated nerve fibers with a diameter of 0.3 to 0.9 m decreased in the elderly group than in the adult and middle aged groups. The total length of the myelinated nerve fibers with a diameter of 0.7 to 0.8 micron m decreased by 52.3% (6.602 km) in the elderly group (6.602 km), and the length of the myelinated nerve fibers in the other diameter segments was changed. The total length of myelinated nerve fibers with a diameter of 1.5 ~ 1.6 mu m increased by 4.55 times (P0.05) in the elderly group (0.614 km) than in the adult group (0.114 km). In the corpus callosum, the total length of the myelinated nerve fibers with a diameter of 0.4 to 0.7 um m increased in the elderly group than in the adult and middle aged groups, but the difference was not statistically significant; The total length of myelinated fibers with a diameter of 1.2 to 1.3 m (0.189 km) increased 1.86 times (P0.05) and 1.55 times (P0.05) in the elderly group (0.066 km) and in the middle and old age group (0.074 km), and the total length of the myelinated fibers with the diameter of 1.4 to 1.5 mu (0.113 km) increased by 21.6 times (P0.05) in the elderly group (0.113 km) than in the adult group (0.005 km).
4.5 the volume of myelinated nerve fibers in the middle segment of the corpus callosum was 27.84 + 1.29mm~3 in the young group and 29.09 + 1.39 mm~3 in the middle and old age group; the volume of myelinated nerve fibers in the elderly group was 20.12 + 1.41 mm~3.. The volume of myelinated nerve fibers was significantly smaller than that in the adult and middle aged groups (P0.05). There was a positive correlation between the volume of medullary nerve fibers in the middle segment and the volume of the corpus callosum (r = 0.869, P0.01). There was a positive correlation between the volume of myelinated nerve fibers in the pressure part and the volume of the corpus callosum (r = 0.931, P0.01).
4.6 the medullary sheath volume of the myelinated nerve fibers in the elderly group was significantly lower than that in the adult group and the middle aged group (P0.01). The myelin sheath volume of the myelinated nerve fibers in the press did not change significantly.
4.7 the diameter of the myelinated nerve fibers, the diameter of the axon and the thickness of the myelin sheath in the middle part of the corpus callosum and the average value of the medullary sheath thickness were no obvious old changes. According to the diameter of the myelinated nerve fibers, the myelinated fibers were segmented and the myelin thickness in different diameter segments had obvious aging changes. The pulp of the myelinated nerve fibers with relatively large diameter was the pulp. The thickness of the sheath increased with age. The myelin thickness of the myelinated nerve fibers in the middle and old age groups increased significantly (P0.01, P0.05) in the middle of the corpus callosum and in the middle-aged and old age groups. The myelin thickness of the myelinated nerve fibers with the diameter of 1.5 ~ 1.6 m in the middle and old age group was smaller than that of the adult group (P0.05), and the older group was compared with the middle age group (P0.01, P0.05). In the elderly group (P0.05), the myelin thickness of myelinated nerve fibers in the aged group increased significantly (P0.05) at the corpus callosum pressure, with the medullary sheath thickness of the myelinated nerve fibers with the diameter of 0.9 to 1 mu and 1.1 ~ 1.2 mu m.
4.8 the difference between the outer circumference and the internal circumference of the middle corpus callosum and the pressure part, and the average value of the ratio between the two groups were not significantly changed. In the middle of the corpus callosum, the difference in the length of the circumferential length increased in the elderly and the middle aged and old groups when compared with the adult group, and the myelinated nerve fibers with the diameter more than 0.9 m in diameter were increased. In the adult group, the myelin sheath of the myelinated nerve fibers with a diameter greater than 0.9 m in diameter increased the ratio of the inner circumference in both the elderly and the middle and old groups. The difference in the length of the medullary and the change of the ratio of the intramedullary sheath to the medullary sheath thickened with the increase of age. The change of the ratio of the difference of the inner circumference and the outer circumference of the compression part and the outer part of the myelin sheath showed that the myelin sheath of the myelinated nerve fibers with relatively large diameter in the middle part thickened with the increase of age.
5 Conclusion
5.1 This study showed that there was no significant change in the pressure volume of the corpus callosum in the aged, and the middle volume of the corpus callosum decreased significantly in the aged.
5.2 A significant decrease in the total length of small-diameter myelinated nerve fibers in the middle part of the corpus callosum may be one of the important reasons for the significant decrease in the volume of the middle part of the corpus callosum in the elderly.
5.3 The length of the larger diameter myelinated nerve fibers in the corpus callosum increased with age.
5.4 the medullary sheath thickness of the medullary nerve fibers in the middle and pressure parts of the corpus callosum increased with age, but the thickness of the myelinated myelin sheath in the smaller diameter was not obvious.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：R322.81
【参考文献】
相关期刊论文 前2条
1 徐tr;李琛;杨姝;张伟;卢伟;唐勇;;运用新的体视学方法研究大鼠胼胝体及胼胝体额区有髓神经纤维[J];第三军医大学学报;2009年01期
2 杨姝;李琛;张伟;汪维伟;唐勇;;大鼠大脑白质及白质内有髓神经纤维老年性改变的体视学研究[J];解剖学报;2007年06期
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