微囊化PC12细胞脑内移植治疗帕金森病的实验研究

目的观察微囊化PC12细胞脑内移植对帕金森病(PD)大鼠模型的治疗作用。方法以6-OHDA分两点注入大鼠纹状体制备PD模型。应用国产新型材料壳聚糖制成的海藻酸钠一壳聚糖一海藻酸钠(ACA)微囊包裹PC12细胞，分别将微囊化PC12细胞、裸PC12细胞、空微囊移植入PD模型鼠损伤侧纹状体内，以阿朴吗啡检测移植前后大鼠旋转行为的差异。行纹状体和黑质的HE染色和酪氨酸羟化酶免疫组化染色观察其病理形态学的变化。对移植的微囊化PC12细胞回收后再培养，以MTT和台盼兰检测细胞活性。结果微囊化PC12细胞移植能够改善PD模型鼠的旋转行为，与移植前和空微囊移植组相比有显著差异(P＞O．05)，症状改善至少持续3个月。裸PC12细胞移植组大鼠的旋转行为也有改善，与移植前相比有统计学差异(P＜O．05)，但仅持续了2个月，移植8周后又渐回到移植前水平，且部分大鼠颅内有致死性肿瘤形成。空微囊移植组移植前后大鼠的旋转行为无明显差异(P＞O．05)。回收微胶囊内的PC12细胞再培养生长良好，MTT法和台盼兰法检测显示细胞具有生物活性。结论微囊化PC12细胞脑内移植能够改善阿朴吗啡诱发的PD模型鼠的旋转症状，ACA新型微包囊能够起到有效的免疫隔离和抑制肿瘤形成的作用。     

微囊化PC12细胞移植治疗帕金森病的实验研究

目的 研究治疗帕金森病的一种新方法。方法 采用免疫隔离技术—微囊技术将能分泌多巴胺的PC12细胞包裹后，移植到帕金森病大鼠脑内，观察阿朴吗啡诱发病鼠旋转行为变化，高效液相色谱电化学法测定移植区多巴胺含量，酪氨酸羟化酶(TH)抗体免疫组织化学染色观察移植区阳性细胞表达。结果 帕金森病大鼠阿朴吗啡诱发旋转行为明显改善，不同时相点的移植区多巴胺含量较对照组明显升高，而未行微囊化的PC12细胞移植则会有致死性肿瘤形成。移植后3月，大鼠脑内微囊完整，仍有TH阳性PCl2细胞存活。结论 微囊化PC12细胞移植，可避免药物治疗、主体定向毁损手术、胎脑移植等方法的诸多弊端，因此是一种新的有效的治疗帕金森病的方法。     

转基因星形胶质细胞脑内移植治疗帕金森病大鼠的研究

目的　评价酪氨酸羟化酶 (TH)基因转染的星形胶质细胞移植入帕金森病 (PD)模型大鼠脑内后对旋转行为改善作用。方法　用pcDNA3 1/TH质粒转染原代培养的星形胶质细胞 ,采用免疫组化及RT PCR方法检测到TH表达后 ,将转基因的星形胶质细胞移植入PD模型大鼠脑纹状体内 ,观察PD大鼠的旋转行为变化情况。结果　移植后共观察 12周 ,转基因细胞移植组PD大鼠 (n =10 )的旋转行为明显改善 (P <0 0 5 ) ,改善情况在 2～ 8周最显著 ,对照组大鼠 (n =10 )的旋转行为无变化。结论　转基因的星形胶质细胞脑内移植后可短期改善PD大鼠的旋转行为 ,星形胶质细胞有可能作为有效的载体细胞。     

铁离子对黑质纹状体多巴胺神经元毒性作用的实验研究

目的 探讨铁离子对黑质纹状体多巴胺神经元的毒性作用。方法 采用立体定向偏侧大鼠黑质内注入50μg FeCl3和FeCl2，4周后用阿朴吗啡诱导动物行为学变化，高效液相色谱(HPLC)检测纹状体内多巴胺、去甲肾上腺素、肾上腺素递质含量的变化，免疫组化观察黑质多巴胺神经元和胶质细胞的改变。结果 FeCL3和FeCL2均可引起注射侧纹状体内DA含量选择性降低，而NA、A含量无显著改变；注射侧黑质内DA神经元显著缺失、胶质细胞显著增生；FeCL3组阿朴吗啡诱导大鼠向同侧旋转行为，FeCL2组大鼠于术后即出现特征性自发性对侧旋转行为，阿朴吗啡不能诱发其旋转。结论 铁离子对黑质纹状体多巴胺神经元具有毒性作用，Fe^3 作用最强，胶质细胞的增生可能参与了这一毒性作用过程。     

GFP转基因小鼠神经干细胞移植治疗大鼠帕金森病的实验研究

目的观察GFP(绿色荧光蛋白)转基因小鼠胚胎神经干细胞植入帕金森病大鼠纹状体后的存活、分化情况及治疗作用。方法建立PD模型大鼠及体外培养神经干细胞,然后将GFP转基因小鼠神经干细胞定向植入帕金森病大鼠毁损侧纹状体内,于移植后不同时间诱发旋转行为,并与对照组相比,观察症状的改善,并用酪氨酸羟化酶(TH)免疫组织化学染色方法检测移植GFP转基因小鼠神经干细胞的存活及分化状况。结果 GFP转基因小鼠神经干细胞脑内移植后,帕金森病大鼠的旋转行为明显改善。移植后2至4周时可检测到成片或散在的TH免疫阳性细胞。结论 GFP转基因小鼠神经干细胞移植至帕金森病大鼠纹状体后,可分化为多巴胺能神经元并能改善旋转症状。     

脑内移植骨髓间质干细胞治疗帕金森病模型大鼠的实验研究

目的 探讨骨髓间质干细胞(mesenchymal stem cells,MSCs)移植治疗帕金森病(parkinson's disease,PD)大鼠的可行性及可能的机制.方法 移植Brdu标记的MSCs到模型大鼠的纹状体内.术后4个月中,定期对大鼠进行旋转行为学实验测试.并分别在术后2周和4个月时进行脑内针道处及移植区免疫组化检测TH和Brdu的表达.结果 Brdu标记的MSCs移植到模型大鼠的纹状体内,术后2周时移植针道处及针道周围可见Brdu阳性外源MSCs,并有外源性细胞表达TH,术后4个月时移植针道内仍可以看到MSCs存活.MSCs移植的PD模型大鼠症状较PBS注射组行为学明显改善.结论 移植MSCs到大鼠PD模型的纹状体内能成活,且分化细胞能表达TH蛋白,大鼠PD模型行为学症状明显改善.     

微囊化牛肾上腺嗜铬细胞植入偏侧帕金森病样猴脑的长期效应：行为和组织学观察

目的 了解微囊化牛肾上腺嗜铬细胞(APA-BCC)脑内移植对纠正偏侧帕金森病(PD)样猴异常行为的长期效应和脑组织学变化。方法 观察6只右侧脑尾状核及壳核接受了APA微囊、BCC或APA-BCC植入的PD样猴的行为变化及移植后14个月，28个月的脑组织形态学改变。结果 (1)植入空微囊28个月猴的PD样症状始终无改善；植入APA-BCC或BCC的PD猴，3d后其PD症状开始得到明显改善；植入BCC的改善效应持续1个月或2个月；3只植入APA-BCC的PD猴的行为改善效应持续时间明显长于BCC组，分别超过14个月，28个月和48个月。(2)猴脑组织学观察显示植入APA-BCC后行为改善良好的PD样猴脑移植区内存在大量形态完整的微囊，囊内可见存活的BCC，移植区周边纹状体内TH阳性纤维密度明显高于对侧；行为改善持续时间短的猴脑内未见完整微囊及存活的BCC；植入BCC的猴脑内未见存活的BCC，见局灶瘢痕样组织反应；植入空微囊的猴脑组织内存在微囊。结论 植入PD样猴脑内的APA-BCC 28个月时仍完好存在并可纠正异常行为，周围组织反应轻微。     

TH基因修饰的神经干细胞移植治疗帕金森病的实验研究

目的 探讨TH基因修饰的神经干细胞脑内移植对帕金森病(PD)的治疗作用。方法 构建pN：ATH逆转录病毒载体质粒，用PA317细胞包装，G418筛选阳性克隆，病毒上清感染神经干细胞，将表达TH的神经干细胞植入：PD大鼠纹状体内，测定：PD大鼠旋转行为改善，DA和DOPAC含量变化，以及TH在纹状体的表达。结果 TH基因修饰的神经干细胞移植8周时能显著降低PD大鼠旋转行为，增加纹状体DA和DOPAC含量，TH在纹状体内的表达增加，疗效好于单纯神经干细胞移植组。结论 TH基因修饰的神经干细胞移植对PD大鼠有明显的治疗作用，可望为PD治疗提供新的途径。     

菲立磁标记骨髓基质细胞动脉移植治疗帕金森病的实验研究

目的:探讨应用骨髓基质细胞(BMSCs)经颈动脉移植治疗帕金森病(PD)大鼠的机制及疗效,以及菲立磁(Feridex)标记的BMSCs移植入PD大鼠体内后,MRI示踪观察的可行性。方法:建立PD大鼠模型,体外分离培养扩增SD大鼠BMSCs,从右侧颈动脉移植治疗10只PD大鼠,移植后进行行为学观察和MRI示踪观察。结果:移植治疗的PD大鼠阿扑吗啡诱发旋转实验较对照组明显减少;组织学和MRI示踪发现移植的BMSCs在PD大鼠脑内存活、迁移,并向神经细胞方向分化。结论:BMSCs移植能显著改善PD大鼠的生物学行为,利用MRI技术可以对菲立磁标记的BMSCs进行活体追踪。     

微囊化PC12细胞移植后帕金森病大鼠旋转行为变化研究

目的观察微囊化PC12细胞移植后帕金森病大鼠旋转行为的变化。方法采用免疫隔离微囊技术将能分泌多巴胺的PC12细胞包裹后,移植到帕金森病大鼠脑内,观察阿扑吗啡诱发病鼠旋转行为的变化,酪氨酸羟化酶(TH)抗体免疫组化染色观察移植区阳性细胞的表达。结果帕金森病大鼠旋转行为有明显改善,由移植前(11.88±2.04)圈/min减少为移植后(3.46±1.01)圈/min。移植后3个月,大鼠脑内微囊完整,仍有TH阳性PC12细胞存活。结论微囊化PC12细胞移植可明显改善帕金森病大鼠的旋转行为。     

Cortical lesions interfere with behavioral recovery from unilateral substantia nigra lesions induced by brain grafts

Effects of aspiration lesions of the cerebral cortex on the behavioral effects of intraventricular substantia nigra grafts were investigated. Apomorphine-induced rotational behavior consequent to unilateral lesions of the substantia nigra was used as a behavioral measure. Substantia nigra grafts reduced rotational behavior in animals with sham cortical lesions. Cortical lesions also decreased rotational behavior and, in these animals, no additional decrease in rotational behavior was induced by substantia nigra grafts. It is concluded that cortical lesions alter striatal circuitry so as to preclude a behavioral effect of substantia nigra grafts.     

Functional brain tissue transplantation: reversal of lesion-induced rotation by intraventricular substantia nigra and adrenal medulla grafts, with a note on intracranial retinal grafts

Using a rotational behavior animal model, it has been found that embryonic substantia nigra (SN) can be homologously transplanted to the brain lateral ventricles to reverse the effects of SN lesions. These grafts were found to decrease the lesion-induced rotational behavior that was provoked either by apomorphine or amphetamine. This effect was not duplicated by grafts of other embryonic brain regions. The SN grafts produced a dopaminergic reinnervation of the dorsomedial striatum that appeared to be responsible for the behavioral amelioration. Long-term studies demonstrated that behavioral efficacy and survival continued for at least 6 months to 1 1/2 years. The catecholaminergic "chromaffin" cells of the adrenal medulla possess a remarkable ability to change morphologically and biochemically in response to their environmental hormonal milieu. This plasticity was exploited by transplanting adrenal medulla to the rat brain to reverse the effects of SN lesions. This tissue changed biochemically by producing large amounts of dopamine, and morphologically, by extending coarse fiber processes. Although these grafts appeared to secrete catecholamines, they did not reinnervate the striatum. Rotational behavior was reduced by these grafts, apparently as a consequence of the catecholamine secretion. When adrenal chromaffin tissue was obtained from 1- or 2-year-old donors, however, lesion-induced rotational behavior was not reduced. It is suggested that adrenal chromaffin cell grafts from young donors possess a biochemical plasticity that is the basis for the behavioral effect, but that this plasticity is lost with maturity of the tissue. An important issue for future applications of these procedures is the immunological privilege of the brain lateral ventricles. We found that both embryonic brain tissue and adult adrenal medulla "allografts" from Brown Norway rat donors consistently survived for at least 6 months in the ventricles of Fisher 344-strain rat hosts. These strains differ in major histocompatibility antigens and, as expected, Fisher 344 rats rapidly rejected Brown Norway skin grafts. Skin graft survival times were not influenced by the presence of established brain grafts, nor did brain grafts elicit systemic humoral immunity. Conversely, however, independent elicitation of systemic immunity by skin grafting resulted in the rejection of long-established brain grafts concomitant with rejection of the skin grafts. Rotational behavior in Fisher 344 hosts was reduced by brain grafts from Brown Norway donors; yet, after rotation had been reduced it could be brought back to baseline levels through systemic immunization and associated brain graft rejection.(ABSTRACT TRUNCATED AT 400 WORDS)     

Rapid eye movement (REM) sleep deprivation in 6-OHDA nigro-striatal lesioned rats with and without transplants of dissociated chromaffin cells

Since both REM sleep deprivation and unilateral 6-OHDA lesions induce supersensitivity of DA receptors, the purpose of this study was to determine whether the response of rats with such lesions would be modified by REM sleep deprivation. In addition, the effect of grafts of dissociated chromaffin cells was also tested. Rats with 6-OHDA lesions were subjected to 24 or 72 h of REM sleep deprivation and tested with various doses of apomorphine to determine turning behavior frequencies. At end of those experiments, the animals were transplanted with dissociated chromaffin cells and turning behavior was tested again. The results showed that REM sleep deprivation nearly doubled the turning behavior frequency, that chromaffin cell grafts decreased it, but that REM deprivation in grafted animals still seemed to produce an increase of post-synaptic supersensitivity independent of denervation. The results were discussed in terms of the possible relationship of sleep with Parkinson's disease through the DA system.     

Transplantation of microencapsulated bovine chromaffin cells reduces lesion-induced rotational asymmetry in rats

Surrounding bovine chromaffin cells by a semipermeable membrane may protect the transplanted cells from a host immune response and shield them from the inflammatory process resulting from the surgical trauma. Encapsulation of the chromaffin cells was achieved by inter-facial adsorption of a polycation on a polyanionic colloid matrix in which the chromaffin cells were entrapped. Basal and potassium-evoked release of catecholamines from encapsulated bovine chromaffin cells was analyzed over a 4-week period in vitro. Norepinephrine and dopamine release remained constant over time whereas epinephrine release significantly decreased. The chromaffin cells also retained the capacity for depolarization-elicited catecholamine release 4 weeks following the encapsulation procedure. Morphological analysis revealed the presence of intact chromaffin cells with well-preserved secretory granules. Striatial implantation of chromaffin cell-loaded capsules significantly reduced apomorphine-induced rotation compared to empty polymer capsules in animals lesioned with 6-hydroxydopamne frr at least 4 weeks. Intact chromaffin cells expressing tyrosine hydroxylase and dopamine-β-hydroxylase were observed in all capsules implanted in the striatum for 4 weeks. The assessment of the clinical potential of transplanting encapsulated adrenal chromaffin cells of either allo- or xenogeneic origin for Parkinson's disease will require long-term behavioral studies. The present study suggests, however, that the polymer encapsulation procedure may offer an alternative to adrenal autografts as a source of dopaminergic tissue.     

Effects of adrenal medulla grafts on plasma catecholamines and rotational behavior.

The mechanisms by which adrenal medulla grafts influence the function of host brains in animal models of Parkinson's disease are unclear. To explore this issue, fragments of adrenal medulla or sciatic nerve were transplanted into the lateral ventricle of bilaterally adrenalectomized (ADX) or sham-ADX rats with unilateral 6-hydroxydopamine lesions of the substantia nigra. Additional control group received sham-transplantation surgery. Behavioral effects of these procedures were tested following administration of apomorphine, amphetamine, or nicotine. Plasma catecholamines were measured before and after transplantation surgery. In both ADX and sham-ADX rats, adrenal medulla grafts produced greater decreases in apomorphine-induced rotational behavior than did sciatic nerve grafts or sham-transplanted groups. Decreases in rotation were smaller in ADX than in sham-ADX animals, regardless of graft treatment. Plasma catecholamines increased after transplantation surgery in each of the sham-ADX groups, regardless of graft type. Increases in plasma dopamine concentrations were associated with decreases in rotational behavior. Five months after transplantation, grafted chromaffin cells demonstrated catecholamine fluorescence, tyrosine hydroxylase (TH) and chromogranin A immunoreactivities, and expression of TH mRNA. It is concluded that adrenal medulla grafts produce decreases in apomorphine-induced rotation through a combination of two independent effects. One is a specific effect of adrenal medulla grafts. The second is a nonspecific effect that requires an intact adrenal gland and may be related to increases in plasma catecholamine concentrations.     

Intrastriatal Transplantation of Rat Adrenal Chromaffin Cells Seeded on Microcarrier Beads Promote Long-Term Functional Recovery in Hemiparkinsonian Rats

Possible biologic treatments for Parkinson's disease, a disorder caused by the deterioration of dopaminergic neurons bridging the nigrostriatal system, have recently focused on fetal cell transplantation. Because of ethical and tissue availability issues concerning fetal cell transplantation, alternative cell sources are being developed. The adrenal medulla has been used as a cell transplant source because of the capacity of the cells to provide catecholamines and to transform into a neuronal phenotype. However, adrenal tissue transplants have shown limited success, primarily because of their lack of long-term viability. Recently, seeding adrenal chromaffin cells on microcarrier beads has been shown to enhance the cell viability following neural transplantation. In the present study, we further investigated whether transplantation of rat adrenal chromaffin cells seeded on microcarrier beads into the striatum of 6-hydroxydopamine-induced hemiparkinsonian rats would result in a sustained functional recovery. Behavioral tests using the apomorphine-induced rotational and elevated body swing tests up to 12 months posttransplantation revealed a significant behavioral recovery in animals that received adrenal chromaffin cells seeded on microcarrier beads compared to animals that received adrenal chromaffin cells alone, medium alone, or beads alone. Histological examination of tissue at 14 months posttransplantation revealed evidence of tyrosine hydroxylase-positive cells and an on-going glial response in animals transplanted with adrenal chromaffin cells seeded on microcarrier beads, in contrast to absence of such immunoreactive responses in the other groups. These findings support a facilitator role for microcarrier beads in transplantation of adrenal chromaffin cells or other cells that are easily rejected by the CNS.     

NGF-producing transfected 3T3 cells: Behavioral and histological assessment of transplants in nigral lesioned rats

The rodent fibroblast clonal cell line, 3T3, was retrovirally transfected with the rat nerve growth factor (NGF) gene and selected for NGF synthesis. This study tested the hypothesis that transplanted 3T3 cells, transfected to secrete nerve growth factor (3T3^NGF+), change motor behavioral indices created by striatal denervation in a dose-dependent fashion. 3T3^NGF+ cells were transplanted into the lateral ventricle of rats following ipsilateral lesions of the substantia nigra pars compacta by stereotaxic injections of 6-hydroxydopamine (10 μg), an established lesion model. Control groups included vehicle injections and transplanted untransfected cells. The extent of the lesions was measured by determining rotational behavior before and two weeks after transplantation. Immediately prior to transplantation, cells were incubated with the fluorescent dye marker, Dil. To assess cell viability, whole brains were cryosectioned and examined for Dil-labeled 3T3 cells using fluorescent microscopy. The number Uf Dil-labeled profiles in five animals per group were counted in at least five noncontiguous sections per animal. From these data a statistically derived estimate of viable, transplanted 3T3 cells was obtained. The number of surviving transplanted cells correlated with the behavioral changes measured. The 3T3NGF + transplants reduced rotational behavior, while control 3T3 transplants exacerbated rotational behavior. Thus, while NGF delivery was found to be beneficial, it was apparent that naive 3T3 had detrimental effects. These results underscore the importance of making doseresponse measurements when attempting transplantbased modifications of CNS behavior. © 1995 Wiley-Liss, Inc.     

Protective effect of caffeine against neurodegeneration in a model of Parkinson's disease in rat: behavioral and histochemical evidence

Epidemiological studies have consistently demonstrated an inverse association between coffee consumption and Parkinson's disease (PD). This study was designed to investigate the beneficial effect of caffeine at a dose comparable to that of human exposure in a model of PD. For this purpose, unilateral intrastriatal 6-hydroxydopamine (6-OHDA)-lesioned rats were pretreated with caffeine (20 mg/kg; i.p.) 1 h before surgery and treated twice a day (10 mg/kg) for 1 month. Apomorphine-induced rotations and number of Nissl-stained neurons of substantia nigra pars compacta (SNC) were counted. The results demonstrated that caffeine administration for 1 month could attenuate the rotational behavior in lesioned rats and protect the neurons of SNC against 6-OHDA toxicity.     

High frequency stimulation of the subthalamic nucleus improves treadmill locomotion in unilateral 6-hydroxydopamine lesioned rats

This study investigated the influence of electrical stimulation of the subthalamic nucleus (STN) on motor impairment induced by unilateral 6-hydroxydopamine (6-OHDA) lesions in the medial forebrain bundle. Rats were trained to walk on a treadmill and then implanted with microelectrode arrays in and near the STN. The neurotoxin 6-OHDA was injected into the medial forebrain bundle (MFB) unilaterally to produce a targeted lesion of the dopaminergic system. Successful lesions produced impaired treadmill walking behavior. High frequency stimulation (HFS) of the STN improved treadmill walking immediately and restored normal walking patterns. The same HFS failed to evoke visible side effects such as stepping, turning, raising of the head or facial muscle contraction in the absence of treadmill movement, or to change rotational behaviors elicited by the dopamine (DA) agonist apomorphine in unilateral lesioned rats. This suggests that the stimulation did not cause movement by an activation of brainstem locomotor regions or an increase attention leading to movement. Apomorphine-induced rotation may represent an imbalance of dopaminergic activation which remains during HFS. This work may provide a rodent model for deep brain stimulation (DBS) in patients with Parkinson's disease, and be suitable for further investigation of the neural mechanisms underlying the therapeutic effects of DBS.     

Cholinergic regulation of protein III phosphorylation in bovine adrenal chromaffin cells

Protein IIIa (Mr approximately 74,000) and protein IIIb (Mr approximately 55,000), referred to collectively as protein III, are synaptic vesicle-associated phosphoproteins found in all regions of the rat nervous system and in the rat adrenal medulla. In the present study, the presence of protein III and the regulation of its phosphorylation were examined in chromaffin cells isolated from bovine adrenal medullae. Protein III was present in chromaffin cells isolated and purified from bovine adrenal medullae. The levels of protein III were moderately enriched in purified chromaffin cells compared with whole adrenal medullae. Preincubation of chromaffin cells with 32PO4 led to the endogenous phosphorylation of protein III, and phosphopeptide maps of chromaffin cell protein III were similar to those of protein III from bovine cerebral cortex. Treatment of the chromaffin cells with ACh produced calcium-dependent increases in both the phosphorylation of protein III and the release of 3H-norepinephrine. These effects of ACh were mimicked by nicotine but not by muscarine. Other secretagogues (elevated K+, veratridine, Ba2+) also increased both the phosphorylation of protein III and the release of 3H-norepinephrine. However, detailed characterization of the secretagogue-induced increases in protein III phosphorylation and 3H-norepinephrine secretion suggested that protein III phosphorylation was more directly associated with an increase in intracellular calcium than with secretion per se.