成年大鼠脑内5-HT能神经纤维向胎鼠脑皮层移植物内投射的研究

目的：探讨大鼠胎脑皮层组织同种移植后的存活情况，以及宿主脑组织与移植物之间是否能建立神经纤维联系。方法：移植受体(宿主)为正常雄性成年Wistar大鼠。移植供体取自胎龄15～17d的Wistar孕鼠。在移植手术后不同时间取脑切片。用ABC法进行免疫组织化学染色。显示5-HT能神经纤维及其在宿主脑内和移植物中的分布情况。结果：同种胎鼠脑皮层组织移植后存活率为30%，ABC法显示有5-PIT能神经纤维从宿主脑组织长入移植物中。结论：同种胎脑皮层组织移植后移植物与宿主脑组织可以建立神经纤维联系。     

成年大鼠宿主脑内5—HT能神经纤维向胎脑皮层移植物内投射的研究

应用免疫组织化学方法和电镜技术研究大鼠胎脑皮层组织同种移植后的存活情况以及移植物与宿主脑组织之间的神经纤维联系。证实:同种胎脑皮层组织移植后存活率为30％,ABC法研究表明有5-羟色胺能神经纤维从宿主脑组织内长入移植物中,两者之间已建立了神经纤维联系。     

大鼠胎脑组织移植血管构筑形态研究

把 Wistar 胎鼠脑皮质组织移植到同种大鼠的脑缺损腔内.于移植后6月、16月分批活杀。采用 Niss 染色法、墨汁灌注法作光镜和电镜观察.部分作 ABS 灌注电子探针超微扫描观察.并与假手术组对照。结果:见脑移植组植入胎脑存活。移植物与受体脑之间有血循环重建。重建血管构筑特点为,从植入物周边向心性延伸分枝供血。为临床脑移植研究提供参考依据。     

大鼠脑移植血管重建的观察研究

把Wistar胎鼠脑皮质组织移植到同种大鼠的脑缺损腔内。于植后6月,18个月存活的情况下分批处死。采用Niss染色,墨汁灌注作光镜和电镜观察;部分作ABS灌注电子探针超微扫描观察。结果表明脑移植组植入胎脑存活生长,移植物与受体脑之间重建血循环。重建血管构筑特点为,以植入物周边向心性延伸分枝供血。为临床脑移植研究提供参考依据。     

颈上交感神经节脑内移植治疗帕金森病的实验研究

目的研究治疗帕金森病的理想脑内移植物.方法建立SD大鼠帕金森病动物模型,选取SD模型大鼠30只分成3组(移植组12只,对照组12只,空白组6只)用同种成年大鼠颈上交感神经节(SCG)制成细胞悬液,用微量注射器、立体定向仪将细胞悬液植入移植组模型鼠毁损侧尾核头部.每2周观察动物旋转行为变化.6个月后处死动物,制成脑切片,行TH免疫组化及HE染色,切片光镜观察.结果SCG移植后6个月,移植组大鼠旋转行为明显减少.组织学观察发现移植区有TH样阳性细胞存活,且存活数与治疗效果成正比.结论同种异体成年大鼠的SCG脑内移植,移植物能存活并对帕金森病模型鼠有短期治疗作用.     

胎脑组织移植对额叶皮层损伤大鼠辨别学习、记忆之影响

本研究观察了胎脑组织移植对双侧额叶皮层损伤的大鼠学习、记忆功能的影响。学习、记忆再现测验在Y型迷宫中进行。结果表明,胎脑组织移植能促进双侧额叶皮层受损动物明—暗分辨学习及记忆再现功能的恢复,且移植时间长短与其功能恢复呈正相关。组织学检查表明,移植的胎脑组织不仅存活,且分化良好,移植3、6个月后,与宿主脑界面有部分融合,提示移植脑组织与宿主脑可能有纤维联系形成。     

大白鼠脑移植体血管重建的观察及其意义

本文观察了胎鼠脑组织移植大鼠眼前房及脑内后,移植体血循环的重建。移植后1、3、6个月进行切片染色,观察移植体的形态结构及血管构筑。结果表明,存活的脑移植体,重建血循环,但移植体的血管密度低于宿主相应的脑组织,微循环的形态不够完善,血循环不如宿主脑组织充分。个别脑移值体内未见血管长入,其神经细胞变性或消失。部分标本中可见慢性排异反应。结果提示,移植体血循环的建立是移植成功的关键。     

胎脑组织移植免疫排斥反应的实验研究

以Ｗｉｓｔｅｒ大鼠作为受体动物进行同种及异种胎脑皮质组织移植。移植后应用光镜与电镜技术及免疫组化技术在不同时间内对移植物的存活及排斥反应进行了探讨，同时对移植区血脑屏蔽开放情况进行了研究。     

脑组织移植

脑组织移植是一个有着广阔临床应用前景的领域。本文从移植物的选择、制备、植入方式 ,移植物 -宿主间的神经联系 ,移植物对宿主脑功能的影响以及移植后的免疫排斥反应等几方面对脑组织移植做一较为详细的综述     

猴胎脑组织移植实验研究

灵长类动物脑组织移植报道较少,而且局限于胎脑黑质组织移植治疗帕金森病。 本研究参考Willis移植技术及Cotman脑皮质延迟移植技术,将同种猴胎脑组织移植到成年猴的大脑皮质下,并应用组织学及行为学观察方法研究了猴胎脑移植的存活情况。 材料和方法 1.动物:健康成年太行山猕猴10只(雌性4只,雄性6只),年龄5～8岁,体重3～7kg,其中孕猴2只,妊娠10～12周。     

Human fetal neocortical tissue grafted to rat brain cavities survives,leads to reciprocal nerve fiber growth,and accumulates host IgG

The human-to-rat xenograft approach offers possibilities to study aspects of primate cortex development and function without monkeys. Human fetal cortical tissue was grafted to prepared cortical cavities of immunosuppressed host rats. Fetal tissue fragments were collected after routine low-pressure vacuum aspiration abortions performed in the first trimester of gestation. Human derived neurons and human nerve fiber outgrowth were visualized by immunohistochemistry with antibodies against human neurofilament protein 70 kD (hNFP70). Ingrowth from rat host striatum or cortex into the grafts was analyzed by immunohistochemistry with antibodies against tyrosine hydroxylase. Astrocytes were evaluated by immunohistochemistry with antibodies against glial fibrillary acidic protein. The grafts grew into different sizes (1–10 mm in diameter) and contained large numbers of hNFP70-positive nerve fibers. All grafts gave rise to outgrowth of hNFP70-positive fibers into the host with partly a cortical layering; layers III and IV received a majority of the human fibers. In several cases, the graft-derived nerve fibers entered the host brain at restricted areas, while there was no crossing over of nerve fibers at the rest of the graft-host interface. Tyrosine hydroxylase-positive fibers were usually not abundant in the grafts. Interestingly, cases of massive ingrowth occurred from host striatum into the graft in a pattern suggesting “permissive sites” at the graft-host interface in the same way as outgrowth from graft to host was found. Additionally, tyrosine hydroxylase-immunoreactive fibers from host cortex were found to grow into the transplant. Glial fibrillary acidic protein immunoreactivity was increased at the interfaces between graft and host cortex or host striatum. Immunohistochemistry using antibodies against rat IgG indicated the presence of rat IgG within the grafts, and in bordering areas of host brain, possibly indicating a defective graft-host barrier. Taken together, these results show that human cortical-tissue pieces grafted to cortical cavities of immunosuppressed rats survive grafting and develop, and that reciprocal nerve fiber growth between grafts and hosts occur. Human cortical neurons can grow into the rat host brain in a pattern which is partly determined by host cortical architecture. © Wiley-Liss, Inc.     

Chromaffine cells can innervate brain tissue: Evidence from intraocular double grafts

Pieces of fetal cerebral cortex or hippocampal formation were homologously grafted to the anterior chamber of the eye of adult rats. After maturation of the brain grafts in oculo, pieces of adult adrenal medulla were transplanted and placed in contact with the brain tissue. Between 37 and 74 days later, grafts and host irides were removed and examined by Falck-Hillarp histofluorescence for monoamines. When free of adrenocortical tissue, the chromaffine cells of the adrenal medulla formed catecholamine-containing nerve fibers that invaded the adjacent central nervous system grafts. A rich plexus of fine varicose fibers, similar to the locus ceruleus-derived fibers normally present in brain cortices, were found. Less often, thicker fibers, usually adjacent to blood vessels, were also seen. Old brain tissue grafts (450 days) could also be innervated. The presence of sympathetic nerves did not seem to inhibit ingrowth of adrenal medulla-derived fibers. We conclude that adult chromaffine tissue, a nonneural source of catecholamine nerve fibers, is capable of innervating brain tissue.     

Survival and growth of fetal catecholamine neurons transplanted into primate brain

Dopamine and norepinephrine neuroblasts of the ventral mesencephalon, hypothalamus, and dorsolateral pons were transplanted from fetal African green monkeys into multiple brain sites in adult (host) African green monkeys. Tissue was grafted from both early and late gestational age fetuses. Immunohistochemical analysis, with antibodies to tyrosine hydroxylase, a marker of catecholamine-containing neurons, showed large numbers of transplanted catecholamine neurons in host cerebral cortex, corpus striatum and lateral ventricles up to 69 days after transplantation. Serial reconstructions revealed extensive outgrowth of neuronal processes from large numbers of transplanted neurons as well as expansion of the size of transplanted (solid) grafts of fetal brain tissue in the host brain. Some grafts extended from the caudate nucleus into the adjacent lateral ventricles or from the cerebral cortex into the underlying corpus callosum and ventricle. There were dense networks of varicose fibers emanating from the tyrosine hydroxylase positive neurons within intraparenchymal and intraventricular grafts. The size and shape of transplanted neurons retained characteristics common to catecholaminergic neurons from the dissected regions of fetal brain. Thus, a variety of fetal, catecholamine-containing neurons survive transplantation to primate brain and produce extensive neuritic outgrowths. Moreover, rejection of transplanted tissue was not apparent. These findings provide essential information on nerve cell grafting in a species closely related to humans as a prerequisite in the consideration of neural transplants as therapeutic measures in neurological disease.     

Fetal neocortical grafts implanted in adult hypertensive rats with cortical infarcts following a middle cerebral artery occlusion: ingrowth of afferent fibers from the host brain.

This study is focused on the survival of fetal neocortical grafts placed in the infarcted adult host cortex of the spontaneously hypertensive rat and describes the ability of host axonal regeneration into the graft after a focal ischaemic lesion. Five to seven days following ligation of the right middle cerebral artery, dissociated neocortical primordium from fetuses of gestational age 12-18 days was implanted into the infarcted cortical area. Surviving transplants were seen in all rats, although grafts derived from gestational age 12-14 days displayed an irregular morphology rich in sinusoid-like cavities and containing fewer cells of apparently mature neuronal morphology. Grafts from older donors contained perikarya of neuronal appearance; however, they lacked normal cortical lamination. Ten days postgrafting, fibers stained by acetylcholinesterase histochemistry, dopamine-beta-hydroxylase, and 5-hydroxytryptamine immunohistochemistry were found in the grafts, and by 10-23 weeks after transplantation the fiber density had increased substantially. When the retrograde tracer Fluoro-Gold was injected into the grafted tissue, labeled cells were found in several subcortical nuclei of the host, including the nucleus basalis of Meynert, ventral pallidum, thalamus, dorsal raphe, locus coeruleus, as well as the ipsilateral and contralateral neocortex. This study shows that grafts of dissociated neocortical tissue exhibit good survival and growth potential when implanted into infarcted neocortex and that several nerve fiber systems of the adult host have a regenerative capacity sufficient to innervate the grafted tissue.     

Expression of Ia antigen on vascular endothelial cells in mouse cerebral tissue grafted into the third ventricle of rat brain

The mechanisms of the immunological rejection after xenogeneic neural transplantation were investigated with special reference to the expression of class II major histocompatibility complex (MHC) antigen (Ia antigen) on the grafted tissue. Tissue from a newborn mouse cerebral cortex was transplanted into the third ventricle of a 4-week-old rat brain. Infiltration of cytotoxic T-cells into the grafted tissue was investigated immunohistochemically by using a monoclonal antibody (OX-8). The infiltration began 8 days after transplantation and continued until about 4 weeks when the tissue was completely rejected. The expression of Ia antigen was also investigated immunohistochemically. The Ia antigen was first detected in the grafted tissue at 6 days after transplantation. The Ia antigen was considered to be expressed on the vascular endothelial cells judging from the staining patterns and the location of India ink which was perfused from the host's left cardiac ventricle. The perfusion experiments with India ink also revealed that blood was supplied to the grafted tissue from 5 days after transplantation. These results suggest that the expression of Ia antigen on the vascular endothelial cells renders the grafted tissues competent to initiate and participate in the immune reaction. The results also raise a possibility that the expression of Ia antigen is triggered by blood supplied from the host brain. In addition, the results indicate that the Ia-positive blood vessels do not originate in the host brain but are intrinsic to the grafted tissue.     

Meningeal allografts of the 6-day-old rat pineal: a model for a pineal deprived of intracerebral innervation

Pineals from 6-day-old rats were transplanted into an incised bed of the parietal cortex of adult rats, of which 29 survived 4-5 weeks after transplantation. The pinealocytes and capillaries in the grafts were comparable in structure to those in the control. Grafts were demarcated from the host cortical tissue by a double, meninx plus gland-capsule sheath through which no nerve ingrowth was seen into the graft from the host brain. On the other hand, sympathetic nerves originating from the cervical ganglia reached the grafted pineal along the perivascular spaces of blood vessels, as is the case in situ. On this basis. the present meningeal graft is thought to be a model of the pineal gland surviving without its intracerebral neural control.     

Fetal Neocortical Tissue Blocks Implanted in Brain Infarcts of Adult Rats Interconnect with the Host Brain

The purpose of the present study was to study if the connectivity of fetal neocortical tissue blocks placed in ischemic brain infarcts of adult rats would be enhanced in rats housed in an enriched environment. We also investigated whether the enriched housing conditions could enhance the postischemic and postgrafting functional outcome, in terms of motor behavior. This part of the study has been published recently. The middle cerebral artery was ligated on the right side in 37 inbred, adult male spontaneously hypertensive rats. The rats were placed at random either in an enriched environment (groups A and B) or in standard laboratory cages (group C). Three weeks after the artery occlusion, blocks of fetal sensorimotor cortex (Embryonic Day 17) were transplanted into the infarct cavity of rats from groups B and C. After 9 weeks all transplanted rats received an injection, into the graft, of a mixture containing the two tracers Fluoro-Gold and biotinylated Dextran amine. The transplants revealed a structured morphology with whorls and bands of cells reminiscent of normal neocortex. Tracing of efferent transplant to host fibers with biotinylated Dextran amine showed pronounced intrinsic transplant projections, as well as fibers, although significantly fewer, to the host ipsilateral sensorimotor cortex, striatum, and thalamus. Host to transplant projections were revealed by Fluoro-Gold-labeled cells found in the ipsilateral host sensorimotor cortex, the basal nucleus of Meynert, the thalamic ventrobasal, ventrolateral and posterior nuclei, and in the dorsal raphe nuclei. We conclude that fetal frontal neocortical block grafts placed in brain infarcts of adult rats develop a morphology reminiscent of normal neocortex and that both afferent and efferent neural connections, although sparse, are established with the host brain, whether the rats are reared under enriched housing conditions or not.     

Expression of zinc-positive cells and terminals in fetal neocortical homografts to adult rat depends on lesion type and rearing conditions

Zinc-positive neurons and terminals, known to be associated with the glutamatergic projections in the brain, can be demonstrated by the histochemical Timm method and later modifications thereof. The adult rat neocortex contain a uniform lamination of zinc-positive cells with specific projections to, e.g., the striatum. We have previously reported that fetal neocortical grafts implanted in the adult rat neocortex combined with rearing in an enriched environment can improve behavioral functions and reduce the secondary atrophy of thalamus after cortex infarction in adult rats. In order to examine whether the expression of zinc positivity is ontogenetically inherent to neocortical neurons we grafted fetal neocortical tissue to aspiration or ischemic lesions of the frontoparietal neocortex of adult rats, followed by histochemical visualization of the vesicular zinc pool by selenite or sulfide. One further aim of the study was to elucidate to what extent the distribution of zinc-containing neurons and terminals in the grafts depended on rearing under different environmental conditions. The foremost finding of the present study was that the overall density of zinc-containing terminals in fetal cortical transplants placed in brain infarcts of adult spontaneously hypertensive rats is higher when the rats are reared in an enriched environment. Moreover, the presence and expression of zinc-positive neurons and terminals do not seem to be ontogenetically inherent to the cortical neurons as the fetal neocortical grafts placed in aspiration lesions contained no zinc-selenide-positive neurons and few or no zinc-selenide-positive terminals. The presence or expression of zinc-positive cells may thus be induced by ingrowth of fibers and terminals from the host brain as transplants placed in the ischemic lesions expressed both zinc-positive neurons and terminals.     

Transplants of olfactory mucosa in the rat brain I. A light microscopic study of transplant organization

Olfactory mucosa from neonatal rats has been transplanted into the fourth cerebral ventricle or into the parietal cortex of neonatal and adult rats. In these ectopic locations, olfactory neurons continue to differentiate from the neurogenetic matrix (basal cells) of the neuroepithelium. Sensory axon bundles from the newly formed olfactory neurons penetrate the host brain where they branch without forming the characteristic olfactory glomeruli. From the base of the neuroepithelium neural elements migrate into the host cerebral tissue losing their epithelial organization.