Parkinson's disease, trophic factors, and adrenal medullary chromaffin cell grafting: basic and clinical studies

Implantation of glial cell line-derived neurotrophic factor-expressing adipose tissue-derived stromal cells in a rat Parkinson's disease model

In previous studies, the effects of glial cell line-derived neurotrophic factor (GDNF) expressing adipose tissue-derived stromal cells (ADSCs) on Parkinson's disease (PD) models have been studied but have not been elucidated. The present study aims to investigate this phenomenon and trace their differentiation in vivo. In our study, ADSCs were harvested from adult Sprague-Dawley rats, then genetically modified into GDNF-expressing system by lentivirus. The secretion of GDNF from the transduced cells was titrated by enzyme-linked immunosorbent assay (ELISA). Cellular differentiation in vitro was observed after induction. To examine survival and differentiation in vivo, they were injected into the striatum of 6-hydroxydopamine-lesioned rats, whose apomorphine-induced rotations were examined 2, 7, 14 and 21d after grafting. It's found that GDNF-expressing ADSCs can differentiate into neuron-like cells in vitro. Moreover, engrafted GDNF-expressing ADSCs survived at least 90 days post-grafting and differentiated into dopaminergic neuron-like cells. Most importantly, these cells drastically improved the clinical symptoms of PD rats. In conclusion, ADSCs can be efficiently engineered by lentivirus system and deliver a therapeutic level of the transgene to target tissues. GDNF-ADSCs can improve behavior phenotype in the rat PD model. Moreover, ADSCs is a more readily available source of dopaminergic neurons, though a more effective procedure needs to be developed to enrich the number of differentiation.

Evaluation of Intracerebral Grafting of Dopamine-Secreting PC12 Cells into Allogeneic and Xenogeneic Brain

The PC12 pheochromocytoma tumor cell line is derived from a rat adrenal medullary tumor and secretes dopamine. We have previously reported that grafted microencapsulated PC12 cells using agarose and poly(styrene sulfonic acid) survived in the xenogeneic brain without immunosuppression. To investigate whether unencapsulated PC12 cells form a tumor and how they provoke immunological reaction, PC12 cell suspension was implanted into the striatum of Sprague-Dawley rat (allogeneic graft) or guinea pig (xenogeneic graft) and histological analysis using Nissl stain and immunocytochemical analysis using antityrosine hydroxylase (TH) antibody were performed 1, 2, and 4 wk after transplantation. Host animals were not immunosuppressed. PC12 cells formed a mass 1 and 2 wk after transplantation both in allogeneic and xenogeneic brain. These grafted PC12 cells were immunoreactive to anti-TH antibody. Four weeks after transplantation, however, grafted PC12 cells in the allogeneic brain were only found within the restricted area near the site of implantation. In the xenogeneic brain, only the trace of grafted PC12 cells were found around the site of implantation 4 wk after transplantation. In both allogeneic and xenogeneic animals, a number of lymphocytes were found in and around the grafts at all period investigated. These findings indicate that PC12 cells could survive in the allogeneic or xenogeneic brain for 2 wk and were ultimately rejected by immunological reaction by 4 wk after transplantation. Implantation of encapsulated PC12 cells in the allogeneic or xenogeneic brain is considered a safe and effective method for delivering dopamine into the brain because PC12 cells will not form a tumor in the long-term even if capsules are damaged in some reason.

Therapeutic effects of human mesenchymal and hematopoietic stem cells on rotenone-treated parkinsonian mice

To appreciate the potential applications of stem cell technology in neurodegenerative diseases, including Parkinson's disease (PD), it is important to understand the characteristics of the various types of stem cells. In this study, we designed a set of experiments to compare the ability of three types of human stem cells--mesenchymal stem cells (MSCs), bone marrow CD34(+) cells (BM), and cord blood CD34(+) cells (CB)--using rotenone-treated NOD/SCID mice. Rotenone was orally administered once daily at a dose of 30 mg/kg for 56 days to induce a parkinsonian phenotype. Intravenous delivery of CB into rotenone-treated mice was slightly more beneficial than that of MSCs or BM according to both histological and behavioral analyses. Human nucleus (hNu)(+) cells, which are a specific marker of human cells, were observed in the striatum of rotenone-treated mice transplanted with stem cells. These hNu(+) cells expressed tyrosine hydroxylase (TH). Additionally, α-synuclein(+)/TH(+) cells in the substantia nigra pars compacta decreased significantly following stem cell transplantation. Immunohistochemical analysis also revealed that chronic exposure to rotenone decreased glial cell line-derived neurotrophic factor immunoreactivity and that the reduction was improved by each stem cell transplantation. Gene expression analyses revealed that MSCs, BM, and CB expressed several neurotrophic factors. These results suggest that the beneficial effects of intravenous delivery of stem cells into rotenone-treated mice may result not only from a neurotrophic effect but also from endogenous brain repair mechanisms and the potential of intravenous delivery of stem cells derived from an autologous source for clinical applications in PD.

Past, present and future of human chromaffin cells: role in physiology and therapeutics

Chromaffin cells are neuroendocrine cells mainly found in the medulla of the adrenal gland. Most existing knowledge of these cells has been the outcome of extensive research performed in animals, mainly in the cow, cat, mouse and rat. However, some insight into the physiology of this neuroendocrine cell in humans has been gained. This review summarizes the main findings reported in human chromaffin cells under physiological or disease conditions and discusses the clinical implications of these results.

Human fetal chromaffin cells: A potential tool for cell pain therapy

Transplantation of adrenal medulla cells has been proposed in the treatment of various conditions. Indeed, these cells possess a bipotentiality: neural and neuroendocrine, which could be exploited for brain repair or pain therapy. In a previous study, we characterized these human cells in vitro over 7-10 gestational weeks (GW) [Zhou, H., Aziza, J., Sol, J.C., Courtade-Saidi, M., Chatelin, S., Evra, C., Parant, O., Lazorthes, Y., and Jozan, S., 2006. Cell therapy of pain: Characterization of human fetal chromaffin cells at early adrenal medulla development. Exp. Neurol. 198, 370-381]. We report here our results on the extension to 23 GW. This developmental period can be split into three stages. During the first stage (7-10 GW), we observed in situ that extra-adrenal surrounding cells display the same morphology and phenotype as the intra-adrenal chromaffin cells. We also found that the intra-adrenal chromaffin cells could be committed in vitro towards an adrenergic phenotype using differentiating agents. During the second stage (11 to 15-16 GW), two types of cells (Type 1 and Type 2 cells) were identified morphologically both inside and outside the gland. Interestingly, we noted that the Type 2 cells stem from the Type 1 cells. However, during this developmental period only the intra-adrenal Type 2 cells will evolve towards an adrenergic phenotype. In the third stage (17-23 GW), we observed the ultimate location of the medulla gland. Both the in situ results and the in vitro experiments indicate that particular procedures need to be implemented prior transplantation of chromaffin cells. First, in order to obtain a large number of immature chromaffin cells, they must be isolated from the intra and extra-adrenal gland and should then be committed towards an adrenergic phenotype in vitro for subsequent use in pain therapy. This strategy is under investigation in our laboratory.

Cell therapy of pain: Characterization of human fetal chromaffin cells at early adrenal medulla development

Adult adrenal chromaffin cells are being utilized for therapeutic transplantation. With the prospect of using fetal chromaffin cells in pain therapy, we studied their phenotype, proliferative power, function, and growth in vitro and in situ in order to determine the optimal time for implantation. Between 7 and 10 gestational weeks (GW), we isolated, in vitro, two types of chromaffin cells with a noradrenergic phenotype akin to that observed, in situ. Among the adherent chromaffin cells first observed in vitro, only a few samples expressed met-enkephalin, whereas almost all the neurosphere-like colonies, which appeared later, expressed it. However, neither of the two types of populations expressed an adrenergic phenotype in line with that observed in situ. At the upper limits of the voluntary abortion period authorized in France, this phenotype (12 GW) and met-enkephalin expression (13 GW) were evidenced in situ. For the first time in man, we demonstrate the secretion of noradrenaline in vitro by the two populations of cells. Consistent with this result, we also noted dopamine beta hydroxylase (DbetaH) mRNA expression in vitro and in situ within this period. These observations on the expression of these biological factors indicate that 9-10 GW would be the best stage for sampling these cells for preclinical transplantation experiments.

Heparin-binding epidermal growth factor-like growth factor: a component in chromaffin granules which promotes the survival of nigrostriatal dopaminergic neurones in vitro and in vivo

Chromaffin cells can restore function to the damaged nigrostriatal dopaminergic system in animal models of Parkinson's disease. It has been reported that a protein which is released from chromaffin granules can promote the survival of dopaminergic neurones in vitro and protect them against N-methylpyridinium ion toxicity. This neurotrophic effect has been found to be mediated by astroglial cells and blocked by inhibitors of the epidermal growth factor (EGF) receptor signal transduction pathway. Here we report the identification of bovine heparin-binding EGF-like growth factor (HB-EGF) in chromaffin granules and the cloning of the respective cDNA from bovine-derived adrenal gland. Protein extracts from bovine chromaffin granules were found to promote the survival of embryonic dopaminergic neurones in culture, to the same extent as recombinant human HB-EGF. Furthermore, the neurotrophic action of the chromaffin granule extract could be abolished by antiserum to recombinant human HB-EGF. We also show that intracerebral injection of recombinant human HB-EGF protected the nigrostriatal dopaminergic system in an in vivo adult rat model of Parkinson's disease. Intracerebral administration of this protein at the same time as a 6-hydroxydopamine lesion of the medial forebrain bundle was found to spare dopamine levels in the striatum and tyrosine hydroxylase-immunopositive neurones in the midbrain. This study has found that the main component in chromaffin granules responsible for their neurotrophic effect on dopaminergic neurones is HB-EGF. Furthermore, HB-EGF has significant protective effects on nigrostriatal dopaminergic neurones in vivo, making it a potential candidate for use in the treatment of Parkinson's disease.

Immobilization of Arg-Gly-Asp (RGD) sequence in a thermosensitive hydrogel for cell delivery using pheochromocytoma cells (PC12)

A copolymer of N-isopropylacrylamide (98 mole% in the feed) and acrylic acid poly(N-isopropylacrylamide-co-acrylic acid) [p(NiPAAm-co-AAc)], and the adhesion molecule, an Arg-Gly-Asp (RGD)-incorporated hydrogel, were used to entrap pheochromocytoma cells (PC12). In a 28-d culture period, the PC12 cells in the RGD-conjugated gel maintained higher viability and produced dopamine at constant rates, while there was lower cell viability and less dopamine secretion by PC12 cells in p(NiPAAm-co-AAc). PC12 cells cultured in the RGD-conjugated gel would constitute a potentially useful three-dimensional cell system for application in nerve regeneration.

Involvement of adrenal medulla grafts in the open field behavior

Immunohistochemical and behavioral techniques were used to study the effects of adrenal medulla grafts, implanted in striatum after bilateral kainic acid (KA) lesions of this structure, on the open field behavior of mice. KA-induced behavioral changes in leaning, grooming and locomotor activity of the open field test were significantly improved after grafting of the adrenal medulla, and in some respects, fully restored. Immunohistochemical identification showed that grafts contained neuron-like cells with a tyrosine hydroxylase (TH), phenylethanolamine N-methyltransferase, gamma-aminobutyric acid (GABA), choline acetyltransferase (ChAT), and enkephalin-like immunostainings. A likely interpretation of this complex pattern of results is that adrenal medullary grafts may restore the deficits of GABAergic neurons which in turn reverse the abnormalities in emotionality and locomotion. Neurobiologically, these behavioral improvements probably involve GABAergic and catecholaminergic factors of adrenal medulla grafts, although other neuroactive substances, such as acetylcholine and enkephalins, cannot be excluded.

Effects of graft placement site on the survival of adrenal medulla transplants into the brain and its relation with the recovery of motor function

BACKGROUND

Because of their lack of long-term viability, adrenal tissue transplants have shown limited success in alleviating the motor disturbances associated with experimental and pathologic striatal dopamine denervation. In this study, we examined how the graft placement site influences adrenal medulla transplant survival and its relation with the reduction of motor deficits in rats bearing unilateral 6-OHDA lesion.

METHODS

One or 5 microL of fetal adrenal medullar tissue was grafted either inside the striatal parenchyma or into the lateral ventricle in contact with the dopamine-denervated striatum. Motor disturbances, as assessed by apomorphine-induced rotation, were correlated to the graft morphologic survival features.

RESULTS

Apomorphine-induced rotation showed a marginal reduction of 11% in all groups independently of graft survival features or placement site. Intrastriatal transplants showed limited viability characterized by a substantial loss of graft initial volume as well as fewer and smaller chromaffin cells compared to ventricular grafts, which had a reduced loss of graft initial volume and more and larger chromaffin cells.

CONCLUSIONS

Although the lateral ventricle may favor adrenal medulla transplant viability, their induced motor outcome is comparable to that induced by less viable intrastriatal grafts, suggesting that the implanted dopamine-producing cells may interact and influence striatal neurons better when placed in close proximity.

Behavioral evaluation of hemiparkinsonian MPTP monkeys following dopamine pharmacological manipulation and adrenal co-graft transplantation

Bradykinesia and rigidity are the symptoms that most directly correlate with loss of striatal dopamine in Parkinson's disease. In the hemiparkinsonian (HP) monkey, this is represented by paucity of movement as measured by coli puterized movement analysis, diminished manual dexterity on clinical examination, and diminished performance on operant behavioral tasks. The present study used an MPTP-induced HP model in rhesus monkeys to evaluate the effectiveness of adrenal medullary and peripheral nerve co-grafts in diminishing parkinsonian symptoms. Unoperated controls (N = 4), surgical controls with caudate lesioning (N = 4), and caudate co-grafted (N = 4) HP monkeys demonstrated diminished movement in the home cage following MPTP. This behavior persisted in unoperated controls, but improved in both surgical control and co-grafted monkeys. Functional hand dexterity evaluations demonstrated similar impairment in all three groups but only surgical controls and co-grafted monkeys demonstrated improvement. In general, rotational behavior in response to apomorphine was consistent with recovery of function in surgical controls and co grafted monkeys, but marked between-subject variability precluded group statistical analyses. None of the monkeys could perform the operant task using the affected limb following MPTP. However, the performance of two co-grafted animals demonstrated partial recovery. L-dopa improved operant performance, demonstrating a dopaminergic component to the task. The results demonstrate recovery of behavioral function after surgical treatment, with adrenal co-grafted monkeys showing the greatest degree of improvement.

Grafting of encapsulated dopamine-secreting cells in Parkinson's disease: long-term primate study

The transplantation of encapsulated dopamine-secreting cells into the striatum represents one potential means of treating Parkinson's disease. The present study investigated the ability of encapsulated PC12 cells, which are derived from rat pheochromocytoma, to supply L-dopa and dopamine into the primate brain in the long term and to effect functional improvement in the animals. Following polymer encapsulation, PC12 cells were transplanted into the striatum of hemiparkinsonian monkeys. The secretion of L-dopa and dopamine from the encapsulated cells, the morphology of these cells, the histology of the host striatum surrounding the capsule, and functional changes in the host animals were examined 1, 6, and 12 months after transplantation. Analysis of retrieved capsules revealed that the PC12 cells survived and continued to release L-dopa and dopamine even 12 months after transplantation. The histological response of the host brain surrounding the capsules was minimal and there were no signs of immunological rejection or tumor formation. The physical condition of the host animals was good for 12 months, and hematologic and cerebrospinal fluid analysis revealed that no animals suffered from infection or immunological reaction. These PC12 cell-grafted monkeys showed improvements in hand movements after transplantation, effects that lasted for at least 12 months. These results further support the potential use of this approach for the treatment of Parkinson's disease.

The effect of intrastriatal single injection of GDNF on the nigrostriatal dopaminergic system in hemiparkinsonian rats: behavioral and histological studies using two different dosages

Glial cell line-derived neurotrophic factor (GDNF) is a member of the transforming growth factor-beta superfamily and acts as a neurotrophic factor for the nigrostriatal dopamine (DA) system. Although previous studies have shown that pretreatment with GDNF could prevent degenerative changes of nigrostriatal DA system by DA neurotoxin 6-hydroxydopamine (6-OHDA), it is not really known whether GDNF can induce recovery of nigrostriatal DA system after partial lesioning by 6-OHDA. Substantia nigra has been commonly chosen as injection site for GDNF but a limited number of studies have used striatum as injection site where neural transplantation is commonly performed. Unilateral intrastriatal administration of 6-OHDA was performed in Sprague-Dawley rats to create partial lesion of the nigrostriatal DA system. These hemiparkinsonian model rats received a 10- or 100-microg single injection of human recombinant GDNF into the same portion of the striatum 4 weeks after 6-OHDA treatment. Both animals that received a 10- or 100-microg single injection of GDNF showed decreased apomorphine-induced rotation at 2 weeks after injection. More potent and prolonged functional recovery was observed in animals receiving 100 microg of GDNF than in those receiving 10 microg of GDNF. Tyrosine hydroxylase (TH) immunocytochemistry revealed that TH positive DA fiber density in the striatum and the number of DA cell bodies in the substantia nigra were greater in animals receiving 10 or 100 microg of GDNF than those receiving saline. These immunocytochemical results have also shown that 100 microg of GDNF was more potent than 10 microg of GDNF. These morphological and functional results indicate that GDNF treatment 4 weeks after 6-OHDA lesioning could induce recovery of nigrostriatal DA system. Striatum was a good site for GDNF administration for hemiparkinsonian rats and a single injection of 100 microg of GDNF was more potent than 10 microg of GDNF.

Neural transplantation for Parkinson's disease

1. Neural transplantation is one promising approach for the treatment of Parkinson's disease. Fetal substantia nigra cells are a good source of dopamine, but in order to avoid ethical and immunological problems, adrenal medullary chromaffin cells have been investigated as an alternative source. 2. Grafted adrenal medullary chromaffin cells can provide dopamine as well as several neurotrophic factors that affect dopaminergic neurons in the brain. 3. We review experimental studies for application of neural transplantation techniques in Parkinson's disease, including immunological studies, cryopreservation, microvasculature, donor tissue, and direct gene delivery studies performed in our laboratory. Our clinical experience and new approach involving a polymer-encapsulated cell grafting procedure are also described.

GDNF administration induces recovery of the nigrostriatal dopaminergic system both in young and aged parkinsonian mice

Glial cell line-derived neurotrophic factor (GDNF) is a member of the transforming growth factor beta superfamily and acts as a neurotrophic factor for the nigrostriatal dopaminergic system. GDNF was injected stereotaxically into the striatum of young (2 months old) and aged (12 months old) C57BL/6 mice that were treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) 1 week earlier. Immunocytochemical and neurochemical analyses showed significant recovery of the nigrostriatal dopaminergic system both in young and in aged mice. Since Parkinson's disease is a neurodegenerative disorder mainly affecting elderly people, this result demonstrates the potential usefulness of GDNF in treating Parkinson's disease.

Phencyclidine and corticosteroids induce apoptosis of a subpopulation of striatal neurons: a neural substrate for psychosis?

Phencyclidine, a non-competitive N-methyl-D-aspartate receptor antagonist and indirect dopamine agonist, has neuroprotective properties. Phencyclidine, however, can also exert toxic effects and causes degeneration of neurons in the retrosplenial cortex. In this paper we demonstrate that acute administration of a high dose of phencyclidine to rats, (80 mg/kg), also causes death of a subpopulation of striatal neurons. The dying cells exhibited many of the morphological and biochemical features of cells undergoing apoptosis as revealed by a silver methenamine stain, propidium iodide fluorescence histochemistry and a TUNEL procedure. The majority of the dying cells tended to be clustered within the dorsomedial aspect of the striatum. The type of striatal cell undergoing apoptosis was determined by stereotaxically injecting a colloidal gold retrograde anatomical tracer into the major areas of striatal termination prior to the administration of phencyclidine. This procedure demonstrated that phencyclidine induced striatal apoptosis is almost exclusively limited to striatopallidal neurons. A similar series of experiments was conducted to determine whether the synthetic corticosteroid, dexamethasone, also induces apoptosis of striatal neurons. Corticosteroids are known to be toxic to hippocampal neurons and interact with striatal dopamine transmission. Acute administration of dexamethasone, (20 mg/kg), induced apoptosis of a subpopulation of striatal cells. As was the case with phencyclidine, most of the dexamethasone-induced apoptotic striatal cells were striatopallidal neurons located within the dorsomedial striatum. The pathology during the early stages of Huntington's disease is restricted to an equivalent subpopulation of striatal neurons. Many Huntington's patients are extremely psychotic during this stage in the progression of the disease. Psychosis is also associated with the acute administration of both phencyclidine and dexamethasone to humans. We accordingly speculate that the selective loss of striatopallidal neurons in the dorsomedial striatum may represent the neural substrate of many forms of psychosis.

Effect of stereotaxic intrastriatal cografts of autologous adrenal medulla and peripheral nerve in Parkinson's disease: two-year follow-up study

Studies in nonhuman primates with experimental parkinsonism have shown that intrastriatal cografts of autologous adrenal medulla and peripheral nerve yield greater behavioral improvement and graft survival than do adrenal medulla grafts alone. To test these observations, five patients with advanced Parkinson's disease were selected to receive unilateral intrastriatal adrenal medulla-intercostal nerve cografts. They were evaluated using the Core Assessment Program for Intracerebral Transplantation (CAPIT) protocol. Three of these patients also underwent quantitative motor testing for the measurement of upper limb bradykinesia (movement time; MT). Following right flank adrenalectomy, cografts consisting of small fragments of adrenal medullary tissue and minced intercostal nerve were stereotaxically implanted into three targets in the right striatum using computerized tomography guidance. Surgery was uneventful and postoperative magnetic resonance imaging revealed accurate placement of the grafts. No morbidity was encountered. Results of 24 months of clinical and quantitative motor assessments postoperatively are reported. Total UPDRS motor scores in the "off" state improved from a mean preoperative score of 39.5 to 32.1 at 3, 29.7 at 6, 27.6 at 9, 28.5 at 12, 31.4 at 18, and 26.5 at 24 months after surgery. Total timed motor test scores during the "off" state improved 17.9% at 6, 23.3% at 9, 18.2% at 12, 38.2% at 18, and 34.9% at 24 months postoperatively compared to baseline. Movement time showed statistically significant improvement (repeated measures ANOVA, P < 0.05) in the left arm (contralateral to surgery) in all three patients tested. These results indicate that stereotaxic intrastriatal implantation of autologous adrenal medulla-peripheral nerve cografts can be performed safely and clinical improvement from this procedure is sustained for a period of 24 months. The clinical improvement was paralleled by improvement in objective, quantitative motor testing.

Long-term enhanced chromaffin cell survival and behavioral recovery in hemiparkinsonian rats with co-grafted polymer-encapsulated human NGF-secreting cells

The transplantation of genetically modified cells represents one potential means of delivering trophic factors to the brain to support the survival of host neurons and to increase the survival of co-grafted cells. The present study examined the ability of encapsulated baby hamster kidney (BHK) fibroblasts, which were genetically modified to produce human nerve growth factor (hNGF), to provide long-term trophic support to co-grafted adrenal chromaffin cells. Following polymer encapsulation, BHK-hNGF cells were grafted into the striatum of hemiparkinsonian rats together with unencapsulated adrenal medullary chromaffin cells. Secretion of hNGF from the encapsulated cells, morphology of these cells, apomorphine-induced rotational behavior of the host animals, and survival of the co-grafted chromaffin cells were examined 1, 6, and 12 months after transplantation. Analysis of retrieved capsules revealed that the BHK cells survived and continued to release hNGF at a level of 2-3 ng/day even 12 months after transplantation. Although the animals receiving adrenal medulla alone did not show recovery of apomorphine-induced rotational behavior, the animals receiving adrenal medulla intrastriatal hNGF-secreting cells showed a significant decrease (40-50%) in apomorphine-induced rotation within 1 month postimplantation that remained stable for the 12-month test period. Tyrosine hydroxylase immunocytochemistry further revealed that while survival of chromaffin cells without hNGF support was poor, co-grafting of adrenal medulla and BHK-hNGF cells dramatically 926- to 32-fold) increased chromaffin cell survival 1, 6, and 12 months after transplantation. These results demonstrate that (1) encapsulated BHK cells survive for extended periods of time in vivo while continuing to secrete hNGF, (2) the continued secretion of hNGF provides trophic support for co-grafted adrenal chromaffin cells, and (3) the increased chromaffin cell survival is associated with long-term, stable behavioral recovery. These data further support the potential use of this approach for treating Parkinson's disease.

Three-dimensional analysis of vasospastic major cerebral arteries in rats with the corrosion cast technique

BACKGROUND AND PURPOSE

Although mice, rats, and other small animals are commonly used for molecular biology research, their use in the evaluation of cerebral vasospasm after subarachnoid hemorrhage is somewhat problematic because of the correspondingly small size of their cerebral vessels. We have already reported that the corrosion cast technique was useful for evaluating newly formed cerebral vessels in neural grafts in these small animals. In the present study we applied the corrosion cast technique to the evaluation of hemolysate-induced cerebral vasospasm in rats and performed three-dimensional analysis for comparison. The casting was done 10 minutes after the hemolysate injection, so that only acute "vasospasm" was assessed.

METHODS

After withdrawal of 0.1 mL cerebrospinal fluid, 0.2 mL hemolysate (n = 9) or saline (n = 10) was injected into the cisterna magna of male Sprague-Dawley rats weighing between 300 and 350 g. Ten minutes later, perfusion of a semipolymerized casting medium was performed at an injection pressure of 100 to 120 mm Hg. The brains were immersed and corroded in 10% NaOH solution. After these procedures, the basilar artery as well as peripheral vessels was analyzed morphologically with scanning electron microscopy. Conventional histological analysis with the use of paraffin-embedded section with hematoxylin-eosin staining was also performed, and the results were compared with those for the corrosion cast methods.

RESULTS

In the saline-injected group, SEM showed that the inner surface of the basilar artery was smooth and the form of the endothelial cell was printed on the surface of the cast. In the hemolysate-injected group, the basilar artery showed an apparent vasospasm over its entire length, and corrugation was observed on the inner surface of the basilar artery in a three-dimensional fashion. Higher magnification revealed that the nuclei of the endothelial cells were distorted. Local narrowing of the basilar artery and vasospasm in the arteries of the anterior circulation and in peripheral arteries were also observed. Measurement of the inner diameter of the basilar artery showed 37.8% contraction in the hemolysate-injected group compared with the saline-injected group by the corrosion cast method. This degree of vasospasm was similar to that observed by the conventional histological method.

CONCLUSIONS

In this report we show that detailed three-dimensional observation in the rat can be performed qualitatively and quantitatively with the corrosion cast technique. We conclude that this method derives an accurate measurement of the diameter of rat major cerebral arteries and is more reliable for analyzing vasospasm in rats than angiography and other conventional procedures.