大鼠大脑白质、皮质毛细血管的体视学定量研究

目的 观察大鼠大脑白质、皮质内毛细血管总长度、总体积、总表面积和平均直径。 方法 选5只7月龄Long-Evans大鼠。运用免疫组织化学技术及相应的体视学方法,计算白质、皮质内毛细血管的长度密度、体积密度﹑表面积密度和毛细血管的总长度、总体积﹑总表面积、平均直径。 结果 大鼠白质由于组织处理引起的白质体积皱缩率为0.51±0.09。白质毛细血管的总长度、总体积、总表面积、平均直径依次为(30.9±6.2)m、(0.8±0.09)m³、(5.3±0.74)cm²、(5.5±1.1)μm。皮质由于组织处理引起的体积皱缩率为0.57±0.08。皮质毛细血管的总长度、总体积、总表面积、平均直径的近似值依次为(364.8±68.0)m、(7.0±1.6)mm³、(51.6±11.7)cm²、(4.5±0.40)μm。 结论 本研究方法为以后同类型的研究提供了较为理想的方法学借鉴。本研究结果为将来的研究提供了大鼠大脑白质和皮质毛细血管参数的基本数值。     

大鼠海马毛细血管密度的体视学研究

用１８只大鼠海马分别制成连续切片，垂直切片和各向同性均匀随机切片，对海马各区，各层内毛细血管体积分数，表面积密度和长度密度进行计量，结果：海马各区的毛细血管密度以ＣＡ２区最高，其次为ＣＡ１，ＣＡ３，ＣＡ４区最低，但各区间无显著差异，各层中以锥体层毛细血管密度最高，次为多形层和分子层，腔隙层最低，各层具显著差异。     

试用体视学方法观测人鼻粘膜毛细血管密度

采用无偏体视学方法对７例胎儿鼻腔外侧壁粘膜的毛细血管密度作了观测。鼻甲粘膜与鼻道粘膜之间，下鼻甲粘膜与中，上鼻甲粘膜之间，毛细血管密度有显著性差异。下鼻甲粘膜的毛细血管最丰富。     

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

目的 探讨老年大鼠大脑白质及白质内有髓神经纤维的改变.方法 运用透射电子显微镜和体视学方法分别对年轻组和老年组Long-Evans大鼠大脑白质及其内有髓神经纤维进行定量研究.结果 老年组大鼠大脑白质总体积,有髓神经纤维总长度分别下降了24.1%和41%;老年组大鼠有髓神经纤维体积密度、髓鞘体积密度和纤维直径分别增加了30%、23.9%和31%,具有统计学意义.但是有髓神经纤维长度密度、有髓神经纤维总体积和髓鞘的总体积没有显著老年性改变.结论 正常老年大脑的萎缩主要是由白质体积的下降引起的.正常老年大脑白质的有髓神经纤维总长度显著性降低,并且主要是由于白质内细小直径的有髓神经纤维丢失所造成的.     

大脑白质有髓神经纤维髓鞘超微结构定量研究的体视学方法

目的:运用新的体视学方法研究大鼠白质有髓神经纤维髓鞘超微结构,以期为以后各种有关髓鞘超微结构的相关研究提供可靠的方法学依据.方法:6～8月龄雌性Long-Evans大鼠.运用电镜技术及相应的体视学方法计算白质内有髓神经纤维的总长度、有髓神经纤维髓鞘总体积、有髓神经纤维及轴突直径、髓鞘断面面积、髓鞘内外周长、髓鞘平均厚度.结果:获得了正常6～8月龄雌性Long-Evans大鼠有髓神经纤维总长度及髓鞘超微结构的各项数据,两种不同方法得到的髓鞘平均厚度并没有显著性差异.结论:把新的体视学方法和电子显微镜结合起来定量研究了大鼠大脑白质有髓神经纤维髓鞘超微结构,所描述的方法为以后进行髓鞘超微结构的定量研究提供了有用的工具.     

不同切片方法对家兔大脑基底节区毛细血管密度的体视学估计的影响

本用6只成年家兔的基底节，分别制取连续切片、垂直切片和各向同性均匀随机切片，估计节内毛细血管的体积分数、表面积密度和长度密度。结果显示，在不同切片厚度及不同放大倍数下的估计值有显差异，而在同样切片厚度及同样放大倍数的条件下，用不同切片方法所得估计值之间无显差异。本对该结果的意义进行了讨论。     

大鼠肾小体发育中毛细血管形态的变化

目的:探讨大鼠肾小体发育中血管球毛细血管内皮细胞及毛细血管长度、表面积和体积的变化规律.方法:采用光镜、电镜技术,并结合体视学分析的方法,对不同发育阶段大鼠血管球毛细血管内皮细胞及毛细血管长度、表面积和体积的变化规律进行形态学观察和体视学测量.结果:在肾小体发育过程中,毛细血管内皮细胞由厚变薄,内皮孔从无到有,毛细血管袢逐渐增多;从胚龄18d到生后40d,毛细血管的长度和表面积大约增大了271倍,体积大约增大了110倍.结论:大鼠血管球毛细血管在肾小体滤过中起着重要作用.     

短期丰富生存环境对老年雄性大鼠大脑白质及白质内有髓神经纤维的影响

目的 探讨短期丰富生存环境干预对老年雄性大鼠大脑白质及白质内有髓神经纤维的影响.方法 将20只24月龄雄性SD大鼠分别在丰富生存环境条件和普通标准环境下饲养4个月后,从每组随机抽取4只大鼠,用透射电子显微镜和体视学方法比较两组大鼠大脑白质及白质内有髓神经纤维的改变. 结果 丰富生存环境组大鼠的白质总体积,白质内有髓神经纤维总长度和总体积,有髓神经纤维轴突总体积分别较标准对照组显著增大,但有髓神经纤维平均内径、外径、髓鞘总体积、髓鞘平均厚度、髓鞘平均内、外周长、有髓神经纤维断面面积、髓鞘断面面积及轴突断面面积较对照组均无明显差异. 结论 短期丰富生存环境干预对24月龄雄性大鼠的大脑白质和白质内有髓神经纤维均有明显的影响.提示短期丰富生存环境可能促使老年雄性大鼠白质内已经发生脱髓鞘改变的有髓神经纤维出现髓鞘再生.     

双侧眼球摘除对大鼠视交叉上核的影响──免疫组化及光电镜体视学研究

采用双侧眼球摘除大鼠模型，术后存活不同时间，用免疫组化法探讨视交叉上核内ＶＩＰ和ＡＶＰ免疫反应强度和面积的变化；对变化明显的２１ｄ组进一步用光镜和电镜体现学方法进行形态学研究。＜１＞免疫组化研究：ＶＩＤ免疫染色，２１ｄ组免疫反应强度和面积均比对照组降低（Ｐ＜０．０５），２ｄ和７ｄ组免疫反应强度和面积与对照组相比无显著差异。ＡＶＰ免疫染色，三个时间实验组免疫反应强度和面积均与对照组无明显差异。＜２＞体视学研究：实验组ＶＩＰ样神经元胞体体积、胞核体积、核仁平均直径均明显缩小，粗面内质网和高尔基复合体表面积密度明显下降。以上所见提示摘除眼球２ｌｄ时，视交叉上核内直接接受光信息的ＶＩＰ样神经元的免疫活性下降是因阻断光传入所造成的。光传入的阻断和视神经纤维的溃变使视交叉上核中ＶＩＰ样神经元的结构呈现功能性改变，推测这些变化将引起该神经元肽类物质含量的下降。     

大鼠大脑白质及白质内有髓神经纤维的性别与年龄差异

目的:研究正常年轻和中老年组雌雄性大鼠大脑白质及白质内有髓神经纤维之间的性别差异,并探讨大脑发育过程中性别差异随年龄增加的改变。方法:运用透射电子显微镜和体视学方法对6~8月龄的年轻Long-Evans大鼠及18月龄同种中老年大鼠大脑白质及其有髓神经纤维进行定量研究。结果:年轻组雄性大鼠大脑白质、有髓神经纤维及其髓鞘的总体积均显著大于雌性,而中老年组雌性大鼠大脑白质、有髓神经纤维体积密度、有髓神经纤维及其髓鞘的总体积均显著大于雄性。结论:年轻组及中老年组大鼠大脑白质、白质内有髓神经纤维及其髓鞘总体积均存在性别差异,随着年龄的增长,雄性大鼠大脑白质及白质内有髓神经纤维体积的减少较雌性更为明显。     

The total number of white matter interstitial neurons in the human brain

In the adult human brain, the interstitial neurons (WMIN) of the subcortical white matter are the surviving remnants of the fetal subplate zone. It has been suggested that they perform certain important functions and may be involved in the pathogenesis of several neurological and psychiatric disorders. However, many important features of this class of human cortical neurons remain insufficiently explored. In this study, we analyzed the total number, and regional and topological distribution of WMIN in the adult human subcortical white matter, using a combined immunocytochemical (NeuN) and stereological approaches. We found that the average number of WMIN in 1 mm³ of the subcortical white matter is 1.230 ± 549, which translates to the average total number of 593 811 183.6 ± 264 849 443.35 of WMIN in the entire subcortical telencephalic white matter. While there were no significant differences in their regional distribution, the lowest number of WMIN has been consistently observed in the limbic cortex, and the highest number in the frontal cortex. With respect to their topological distribution, the WMIN were consistently more numerous within gyral crowns, less numerous along gyral walls and least numerous at the bottom of cortical sulci (where they occupy a narrow and compact zone below the cortical‐white matter border). The topological location of WMIN is also significantly correlated with their morphology: pyramidal and multipolar forms are the most numerous within gyral crowns, whereas bipolar forms predominate at the bottom of cortical sulci. Our results indicate that WMIN represent substantial neuronal population in the adult human cerebral cortex (e.g. more numerous than thalamic or basal ganglia neurons) and thus deserve more detailed morphological and functional investigations in the future.     

Stereological Investigation of Age‐Related Changes of the Capillaries in White Matter

We, for the first time, investigated the age‐related changes of the capillaries in white matter using immunohistochemistry and stereological techniques. Ten young female (7 months) and 10 aged female (27 months) rats were used. The total length, total volume, and total surface area of the capillaries in white matter of aged rats were all significantly lower than those of young rats. The age‐related changes of the capillaries in white matter may have important implications for age‐related white matter atrophy and age‐related cognitive impairments. Anat Rec 293:1400–1407, 2010. © 2010 Wiley‐Liss, Inc.     

No change in total length of white matter fibers in Alzheimer's disease

White matter changes have been reported as part of Alzheimer dementia. To investigate this, the total subcortical myelinated nerve fiber length was estimated in postmortem brains from eight females (age 79-88 years) with severe Alzheimer's disease (AD) and compared with brains from 10 female control subjects (age 74-92 years). A stereological method for estimating myelinated brain fibers includes sampling systematically, randomly from the white matter, and counting fibers in unbiased counting frames using light microscopy at approximately 6000x magnification. The diameter of each counted fiber was measured to obtain the diameter distribution of myelinated fibers in both groups. The mean total myelinated fiber length was 81,554 km in the AD group and 78,896 km in the control group (P=0.63). All other measured parameters were also unaffected in the AD brains: The mean fiber length density was 248 km/cm3 in the AD group and 247 km/cm3 in the control group; the volume of white matter was 329 cm3 (AD) and 321 cm3 (control) and the volume density of myelinated fibers to white matter tissue volume was 0.30 in AD group and 0.31 in the control group. This is the first study of subcortical brain white matter fiber length using a stereological method on postmortem brains from AD patients and control subjects.     

Stereological study on the submandibular gland in hypothyroid rats.

Most research done on hypothyroidism has focused on physiological and biochemical aspects of the tissues, whilst there has been little work on tissue morphology especially on salivary glands. The present study has used hypothyroid Wistar rats as a model for investigating the effects of hypothyroidism on submandibular gland structure. Two groups of Wistar rats were studied. One was made hypothyroid with methimazole and the second was an untreated euthyroid group (control). They were euthanised after 10 weeks. Submandibular glands were removed and studied. Systematic random transverse sections were obtained from submandibular glands and subjected to morphometric analysis. Volume density and absolute volume of granular, striated and excretory ducts and interlobular connective tissue were estimated by point counting. Volume-weighted mean particle volume of serous and mucous acini was also determined by unbiased stereology. Absolute volume of granular ducts in the submandibular gland of hypothyroid rats was reduced by approximately 50% (p<0.009) whilst that of the striated and excretory ducts and interlobular connective tissue was unaffected. Volume of serous acini was also significantly (p<0.03) lower in hypothyroid rats. These changes suggest that hypothyroidism has an effect on submandibular gland structure, and that this effect occurs mostly in two major exocrine compartments (granular duct and serous acinus) of the gland.     

丹曲林对急性脊髓损伤大鼠脊髓白质的保护作用

目的:探讨丹曲林(dantrolene,DA)对大鼠急性脊髓损伤后脊髓白质的保护作用。方法:采用钳夹法制作大鼠急性脊髓损伤模型(SCI)。将48只成年雄性Sprague-Dawley大鼠体重280~310 g,随机分成3组,每组16只,假手术组(Sham组):只行椎板切除术;SCI组:术前1 d腹腔注射生理盐水;丹曲林处理组(DA组):术前1 d腹腔注射10 mg/kg丹曲林。SCI损伤后3、7、14、21、28 d利用BBB评分量表评估大鼠后肢运动功能恢复情况;术后24 h,利用抗NF200单克隆抗体的免疫荧光组织化学法标记轴突,观察各组轴突的形态和数量变化;Western Blot方法检测各组脊髓损伤部位的髓鞘碱性蛋白(Myelin basic protein,MBP)和环核苷酸磷酸二酯酶(2’,3’-cyclic nucleotide phosphodiesterase,CNPase)的蛋白表达水平。结果:不同时间点SCI组大鼠的BBB评分显著低于Sham组,提示SCI模型制备成功。注射丹曲林后,不同时间点SCI动物的BBB评分明显升高(P0.05),提示丹曲林可促进大鼠后肢运动功能的恢复。NF200免疫荧光组织化学法显示:Sham组轴突长,排列有序、分布均匀;SCI后24 h,NF200+纤维断裂、数量减少、排列紊乱、部分甚至卷曲;给予丹曲林后,NF200+纤维数量显著增多且较长,排列较规则。Western Blot结果显示:SCI组CNPase,MBP蛋白的表达量较Sham组显著降低(P0.01),给予丹曲林后可明显升高两者的表达(P0.01)。结论:丹曲林对急性脊髓损伤大鼠白质具有一定的保护作用。     

Stereological Methods for Estimating the Myelin Sheaths of the Myelinated Fibers in White Matter

In the present study, efficient and unbiased stereological techniques to investigate the myelin sheaths of the myelinated fibers in rat white matter were established. In the present design, four tissue blocks were obtained from the entire white matter of rat brain in a uniform, random fashion. Isotropic, uniform random (IUR) sections were ensured by the use of the isector technique. One section with the thickness of 60 nm was cut from the center of each epon block. Eight to 10 fields of vision were randomly photographed under a transmission electron microscope. The total length of the myelinated fibers and the total volume of the myelin sheaths in the white matter were the products of the length density, volume density, and the volume of the white matter obtained with the Cavalieri principle. The mean areas of the myelinated fibers profiles and myelin sheaths were estimated with the point counting technique. The inner and outer perimeters of the myelin sheaths were estimated by the use of a line grid, and the thickness of the myelin sheaths was estimated by direct orthogonal measurements in uniform, random locations. The described methods will provide very useful tools for future quantitative studies of changes in the myelin sheaths of white matter in various experimental conditions and in various neurodegenerative diseases. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.