Sciatic nerve regeneration in rats subjected to ketogenic diet.

OBJECTIVES: Ketogenic diet (KD) is a high-fat-content diet with insufficiency of carbohydrates that induces ketogenesis. Besides its anticonvulsant properties, many studies have shown its neuroprotective effect in central nervous system, but its influence on peripheral nervous system has not been studied yet. We examined the influence of KD on regeneration of peripheral nerves in adult rats. METHODS: Fifty one rats were divided into three experimental (n = 15) and one control (n = 6) groups. Right sciatic nerve was crushed and animals were kept on standard (ST group) or ketogenic diet, the latter was introduced 3 weeks before (KDB group) or on the day of surgery (KDA group). Functional (CatWalk) tests were performed once a week, and morphometric (fiber density, axon diameter, and myelin thickness) analysis of the nerves was made after 6 weeks. Body weight and blood ketone bodies level were estimated at the beginning and the end of experiment. RESULTS: Functional analysis showed no differences between groups. Morphometric evaluation showed most similarities to the healthy (uncrushed) nerves in KDB group. Nerves in ST group differed mostly from all other groups. Ketone bodies were elevated in both KD groups, while post-surgery animals' body weight was lower as compared to ST group. DISCUSSION: Regeneration of sciatic nerves was improved in KD - preconditioned rats. These results suggest a neuroprotective effect of KD on peripheral nerves.

Air gun impactor--a novel model of graded white matter spinal cord injury in rodents.

Understanding mechanisms of spinal cord injury and repair requires a reliable experimental model. We have developed a new device that produces a partial damage of spinal cord white matter by means of a precisely adjusted stream of air applied under high pressure. This procedure is less invasive than standard contusion or compression models and does not require surgical removal of vertebral bones. We investigated the effects of spinal cord injury made with our device in 29 adult rats, applying different experimental parameters. The rats were divided into three groups in respect to the applied force of the blast wave. Functional outcome and histopathological effects of the injury were analyzed during 12-week follow-up. The lesions were also examined by means of magnetic resonance imaging (MRI) scans. The weakest stimulus produced transient hindlimb paresis with no cyst visible in spinal cord MRI scans, whereas the strongest was associated with permanent neurological deficit accompanied by pathological changes resembling posttraumatic syringomyelia. Obtained data revealed that our apparatus provided a spinal cord injury animal model with structural changes very similar to that present in patients after moderate spinal cord trauma.

Reduction of post-traumatic neuroma and epineural scar formation in rat sciatic nerve by application of microcrystallic chitosan.

Injury of peripheral nerve is associated with the development of post-traumatic neuroma at the end of the proximal stump, often being the origin of neuropathic pain. This type of pain is therapy-resistant and therefore extremely nagging for patients. We examined the influence of the microcrystallic chitosan gel applied to the proximal stump of totally transected sciatic nerve on the neuroma formation and neuropathic pain development in rats. In 14 rats, right sciatic nerve was transected and the distal stump was removed to avoid spontaneous rejoining. In the chitosan (experimental) group (n = 7), the proximal stump was covered with a thin layer of the microcrystallic chitosan gel. In control animals (n = 7), the cut nerve was left unsecured. Autotomy, an animal model of neuropathic pain, was monitored daily for 20 weeks following surgery. Then, the animals were perfused transcardially and the proximal stumps of sciatic nerves were dissected and subjected to histologic evaluation. The presence, size, and characteristics of neuromas as well as extraneural fibrosis were examined. In chitosan group, the incidence and the size of the neuroma were markedly reduced, as compared with the control group; however, there was no difference in autotomy behavior between groups. In addition, extraneural fibrosis was significantly reduced in chitosan group when compared to the control group. The results demonstrate beneficial influence of microcrystallic chitosan applied to the site of nerve transection on the development of post-traumatic neuroma and reduction of extraneural fibrosis, however without reduction of neuropathic pain.

17beta-estradiol and predegenerated nerve graft effect on hippocampal neurogenesis in adult female rats.

OBJECTIVES: The aim of present work was to examine estrogen influence on neurogenesis in the model of predegenerated peripheral nerve grafts implantation into the rat hippocampal dentate gyrus. METHODS: Experiment was carried out on female rats divided into three experimental groups: NO - non-ovariectomized, OV - ovariectomized and E - heterogeneous group with various 17-beta-estradiol substitution after ovariectomy. Proliferating cells were labeled with BrdU. Brains were subjected to immunohistochemical procedures to visualize nestin, GFAP and estrogen receptors (ERalpha and ERbeta). RESULTS: Proliferation rate was highest in E groups with estrogen levels resembling that in proestrus phase. Ovariectomy resulted in higher than in NO group number of new neurons, while high hyperestrogenemia worsened the results. The proportions of nestin-labeled cells correlated in similar way with different hormonal state. We found also distinct co-localization of nestin and GFAP in E group (proestrus). It may suggest the presence of radial glia, a potential source of new neurons in adult mammals. Nerve graft induced ERalpha expression at the site of injury in all groups. Distribution of ERbeta in hippocampus was estradiol-dose-dependent and correlated with cell proliferation. CONCLUSION: In our model, 17-beta-estradiol and predegenerated nerve graft implantation had synergistic effect on hippocampal neurogenesis.

Use of ebselen as a neuroprotective agent in rat spinal cord subjected to traumatic injury.

Spinal cord injury (SCI) causes disturbances of motor skills. Free radicals have been shown to be essential for the development of spinal cord trauma. Despite some progress, until now no effective pharmacological therapies against SCI have been verified. The purpose of our experiment was to investigate the neuroprotective effects of ebselen on experimental SCI. Twenty-two rats subjected to SCI were randomly subjected to SCI with no further treatment (n = 10) or intragastric administration of ebselen (10 mg/kg) immediately and 24 hours after SCI. Behavioral changes were assessed using the Basso, Beattie, and Bresnahan locomotor scale and footprint test during 12 weeks after SCI. Histopathological and immunohistochemical analyses of spinal cords and brains were performed at 12 weeks after SCI. Magnetic resonance imaging analysis of spinal cords was also performed at 12 weeks after SCI. Rats treated with ebselen presented only limited neurobehavioral progress as well as reduced spinal cord injuries compared with the control group, namely length of lesions (cysts/scars) visualized histopathologically in the spinal cord sections was less but cavity area was very similar. The same pattern was found in T2-weighted magnetic resonance images (cavities) and diffusion-weighted images (scars). The number of FluoroGold retrogradely labeled neurons in brain stem and motor cortex was several-fold higher in ebselen-treated rats than in the control group. The findings suggest that ebselen has only limited neuroprotective effects on injured spinal cord. All exprimental procedures were approved by the Local Animal Ethics Committee for Experiments on Animals in Katowice (Katowice, Poland) (approval No. 19/2009).

Expression of tuberin and hamartin in tuberous sclerosis complex-associated and sporadic cortical dysplasia of Taylor's balloon cell type.

Focal cortical dysplasia (FCD) type IIB is a malformation of cortical development characterized by presence of balloon cells. These cells share phenotypic features of giant cells found in tuberous sclerosis complex (TSC), but the relationship between FCD type IIB and TSC is not well established. TSC is an autosomal dominant disorder caused by mutation in either of two genes: TSC1, encoding hamartin, and TSC2, encoding tuberin. Both proteins form a complex inhibiting mTOR signalling pathway and thus regulate cell size and proliferation. In this study, tuberin and hamartin expression was evaluated under a confocal microscope in six cases of Taylor's balloon cell type FCD. Three patients met the clinical criteria for TSC. In three other patients, TSC was excluded based on a panel of clinical and radiological examinations. Additionally, two cases of FCD type I and 3 samples of normal brain tissue were used as a reference group. We found loss of tuberin and hamartin expression in FCD type IIB lesions from patients with TSC. In sporadic FCD type IIB cases, only a few tuberin and hamartin positive cells were detected in the white-grey matter junction and in deeper parts of the white matter. Cortical balloon cells showed loss of both tuberin and hamartin. In contrast, the expression of tuberin and hamartin in FCD type I samples was strong, similarly to normal brain tissue. In conclusion, loss of TSC1 and TSC2 products expression in balloon cells of both cortical dysplasia type IIB in TSC-related and sporadic patients suggests that FCD type IIB may represent the focal form of TSC.

The influence of trkB deficiency on long-term outcome of peripheral nerve injury in mice.

The long-term outcome of peripheral nerve injury is often unsatisfactory, especially if the injury resulted in a gap between transected nerve stumps. Brain-derived neurotrophic factor and its receptor, trkB, are strongly implicated in the early phase of axonal regeneration after injury. We examined the role of trkB in long-term functional and morphological outcome of peripheral nerve injury. The sciatic nerve was transected in wild-type and heterozygous trkB-deficient mice. The nerve was either left cut or immediately sewn up or the gap injury model was performed. The gap was provided with autologous or cross (obtained from other genetic group) graft. Sciatic nerve function as well as autotomy was assessed during 16-week follow-up. The long-term functional outcome of nerve cut or immediately rejoined did not differ between wild-type and trkB-deficient mice. Gap injury provided with nerve graft resulted in better functional outcome in trkB-deficient mice than wild-type animals. Sixteen weeks after the surgery, the animals were sacrificed and histological evaluations were performed. The number of nerve fibres regenerating into the distal stump of transected and rejoined nerves did not differ between wild-type and trkB-deficient animals. TrkB deficiency markedly increased the number of Schwann cells as well as mast cells at the injury site and in the distal stump of the regenerating nerve. TrkB deficient nerves also showed higher expression of bcl-2 protein but lower of trkA and NGF than wild-type ones. Our results show for the first time the possible deleterious role of trkB receptor in long-term outcome of peripheral nerve injury.

Extended magnetic resonance imaging studies on the effect of classically activated microglia transplantation on white matter regeneration following spinal cord focal injury in adult rats.

Spinal cord injuries are still a serious problem for regenerative medicine. Previous research has demonstrated that activated microglia accumulate in spinal lesions, influencing the injured tissues in various ways. Therefore, transplantation of activated microglia may have a beneficial role in the regeneration of the nervous system. The present study examined the influence of transplanted activated microglial cells in adult rats with injured spinal cords. Rats were randomly divided into an experimental (M) and control (C) group, and were subjected to non-laminectomy focal injury of spinal cord white matter by means of a high-pressured air stream. In group M, activated cultured microglial cells were injected twice into the site of injury. Functional outcome and morphological features of regeneration were analyzed during a 12-week follow-up. The lesions were characterized by means of magnetic resonance imaging (MRI). Neurons in the brain stem and motor cortex were labeled with FluoroGold (FG). A total of 12 weeks after surgery, spinal cords and brains were collected and subjected to histopathological and immunohistochemical examinations. Lesion sizes in the spinal cord were measured and the number of FG-positive neurons was counted. Rats in group M demonstrated significant improvement of locomotor performance when compared with group C (P<0.05). MRI analysis demonstrated moderate improvement in water diffusion along the spinal cord in the group M following microglia treatment, as compared with group C. The water diffusion perpendicular to the spinal cord in group M was closer to the reference values for a healthy spinal cord than it was in group C. The sizes of lesions were also significantly smaller in group M than in the group C (P<0.05). The number of brain stem and motor cortex FG-positive neurons in group M was significantly higher than in group C. The present study demonstrated that delivery of activated microglia directly into the injured spinal cord gives some positive effects for the regeneration of the white matter.

Prevention of painful neuromas by oblique transection of peripheral nerves.

OBJECT: Neuroma formation often occurs at the proximal stump of the transected nerve, complicating the healing process after gap injuries or nerve biopsies. Most such neuromas cause therapy-resistant neuropathic pain. The purpose of this study was to determine whether oblique transection of the proximal stump of the sciatic nerve can prevent neuroma formation. METHODS: The sciatic nerves of 10 rats were transected unilaterally at an angle of 30 degrees, and the peripheral segments of the nerves were removed. In 10 control animals the sciatic nerves were transected at a perpendicular angle. Twenty weeks after surgery the nerves were reexposed and collected. The presence of neuromas was determined by two board certified pathologists on the basis of histopathological evaluations. CONCLUSIONS: The oblique transection of peripheral nerves, contrary to perpendicularly transected nerves, is rarely followed by classic neuroma development. Moreover, neuropathic pain is significantly reduced compared with that following the traditional method of nerve transection.

TrkB deficiency increases survival and regeneration of spinal motoneurons after axotomy in mice.

Persisting motor function deficit after peripheral nerve injury often results from axotomized motoneuron death. Brain-derived neurotrophic factor (BDNF) and its receptor, trkB, are known to promote peripheral nerve regeneration. However, the requirement of BDNF and trkB for adult motoneuron survival after peripheral nerve injury is not established. We studied the number of surviving and regenerating motoneurons after sciatic nerve transection in wild-type and heterozygous trkB-deficient mice. The nerve was either left cut or immediately sewed up or the gap injury model was performed. The gap was provided with an autologous or cross (obtained from other genetic group) graft. Sixteen weeks after surgery, the animals were sacrificed and histological evaluations were performed. In order to study the number of regenerating motoneurons, immunofluorescent tracer was applied to the distal stump of the operated nerve. We found that in wild type mice, the decrease in motoneurons after nerve transection was markedly higher than in trkB-deficient animals, regardless of the operation procedure. Nerve transection resulted in the highest decrease in motoneuron number in wild type mice. This decrease was lower if the nerve was re-joined using a cross-graft obtained from a trkB-deficient animal. Interestingly, in trkB-deficient animals, the decrease in motoneuron count did not depend on type of operation and was similar after nerve transection, re-joining or grafting. The number of regenerating motoneurons after nerve transection and re-joining in wild type animals was lower than in trkB-deficient mice. The number of regenerating motoneurons after nerve grafting did not differ between groups. These results provide further evidence for the role of trkB receptor in spinal motoneuron survival and regeneration.

The role of trkB receptor in the formation of post-traumatic neuroma.

The outcome of peripheral nerve injury is often impaired by post-traumatic neuroma developing at the injury site. Neuroma is usually accompanied by neuropathic pain, which is usually resistant to most analgesics and presents a serious clinical problem. The mechanisms underlying post-traumatic neuroma remain unclear, but they are likely associated with regeneration processes. Brain-derived neurotrophic factor (BDNF) and its receptor, trkB, are strongly implicated in axonal regeneration after injury. The aim of this work was to examine the role of trkB in post-traumatic neuroma formation. The sciatic nerve was transected in wild-type and heterozygous trkB-deficient mice. The nerve was either left cut or immediately sewn up or the gap injury model was performed. The gap was provided with an autologous or cross (obtained from another genetic group) graft. Sixteen weeks after surgery, the animals were sacrificed and histologic evaluations were performed. We found very limited or no neuroma formation in wild-type animals, regardless of the surgical procedure. In the majority of trkB-deficient mice, the post-traumatic neuroma was found at the end of the proximal stump of the transected nerve. In the gap injury model, in trkB-deficient animals receiving wild-type graft, there was no neuroma at the join site between the graft and distal stump of the nerve. In contrast, if the graft was autologous, neuroma formed at both joints. We also noticed many more mast cells accumulated at the surgery site in trkB-deficient than in wild-type animals. These results indicate the important role of BDNF receptor in post-traumatic neuroma formation.

Impaired regeneration of bcl-2-lacking peripheral nerves.

OBJECT: The outcome of peripheral nerve damage in still not satisfactory, despite the general capacity of peripheral nervous system to regenerate. The molecular mechanisms underlying nerve regeneration are still not clear, but it is likely that apoptosis regulating genes plays a crucial role in these processes. The aim of the present study was to establish the role of the anti-apoptotic gene bcl-2 in peripheral nerve repair. MATERIAL AND METHODS: Sciatic nerves of bcl-2-deficient and wild type mice were transected, and immediately re-sutured. The regeneration was assessed functionally and morphologically throughout the 4-week follow-up. RESULTS: We found markedly worse sciatic function index outcome, as well as more significant atrophy of denervated muscles in bcl-2 knock-out animals when compared with wild-type ones. The intensity of histological regeneration features, including GAP-43-positive growth cones, Schwann cells and macrophages in the distal stump of the transected nerve, was also decreased. The number of motor and sensory neurons in the relevant cross-sections of spinal cord was similar in both groups of mice. CONCLUSION: We concluded that the bcl-2 gene plays an important role in peripheral nerve regeneration, influencing nerve injury site clearing, fiber regrowth and myelination.

Grafted Activated Schwann Cells Support Survival of Injured Rat Spinal Cord White Matter.

BACKGROUND AND OBJECTIVE: The influence of cultured Schwann cells on injured spinal cord in rats is examined. METHODS: Focal injury of spinal cord white matter at the T10 level was produced using our original non-laminectomy method with a high-pressure air stream. Schwann cells from 7-day predegenerated rat sciatic nerves were cultured, transducted with green fluorescent protein and injected into the cisterna magna (experimental group) 3 times: immediately after spinal cord injury and 3 and 7 days later. Neurons in the brainstem and motor cortex were labeled with FluoroGold (FG) delivered caudally from the injury site a week before the end of the experiment. The functional outcome and morphologic features of neuronal survival were analyzed during a 12-week follow-up. The lesions were visualized and analyzed using magnetic resonance imaging. The maximal distance of expansion of implanted cells in the spinal cord was measured and the number of FG-positive neurons in the brain was counted. RESULTS: Rats treated with Schwann cells presented significant improvement of locomotor performance and spinal cord morphology compared with the control group. The distance covered by Schwann cells was 7 mm from the epicenter of the injury. The number of brainstem and motor cortex FG-positive neurons in the experimental group was significantly higher than in the control group. CONCLUSIONS: The data show that activated Schwann cells are able to induce the repair of injured spinal cord white matter. The route of application of cells via the cisterna magna seemed to be useful for their delivery in spinal cord injury therapy.

Experimental hyperthyroidism increases the effectiveness of predegenerated peripheral nerve graft implantation into hippocampus of adult rats.

PURPOSE: The aim of the study was to ascertain whether experimental hyperthyroidism changes the neurotrophic activity of 14- and 21-day-predegenerated peripheral nerve grafts towards CNS neurites. METHODS: Hyperthyroidism was induced by subcutaneous injections of T_4. Autologous peripheral nerve grafts were implanted into the hippocampus of both euthyrotic and hyperthyrotic animals 14 or 21 days after sciatic nerve transection (groups ET14, Et21, Ht14 and Ht21, respectively). Non-predegenerated grafts were used as a control group (groups EtN adn HtN). Cells extending their neurites into the grafts were traced with FITC-HRP. RESULTS: The number of traced cells in individual groups was as follows: EtN - 39.4 +/- 9.46, Et14 - 1 +/- 0.94, Et21 - 0.6 +/- 0.69; HtN - 95 +/- 19.46; Ht14 - 95.94 +/- 16.3, Ht21 - 99.94 +/- 7.26. CONCLUSIONS: We found that experimentally induced hyperthyroidism strongly enhanced the regeneration of injured hippocampal neurites after implantation of peripheral nerve grafts that were practically inactive in euthyrotic animals.

Do peripheral nerve extracts protect retinal ganglion cells from axotomy-induced death?

PURPOSE: Study the effect of peripheral nerve extracts and BDNF on retinal ganglion cell (RGC) regeneration in adult rats. METHODS: Postmicrosomal fractions were obtained from 7-day, predegenerated, as well as non-predegenerated peripheral adult rats nerves. Autologous connective tissue chambers filled with fibrin were implanted into a gap-injury site in the optic nerve. Chambers contained either fibrin, the fractions, or BDNF. RGCs retrogradely labeled with DiI were counted, the distance covered by regrowing fibers traced with rhodamine B was measured, and number of myelinated fibers in the middle part of the chambers was estimated. RESULTS: BDNF and predegenerated nerve extracts enhanced RGC fiber outgrowth. The regeneration was significantly weaker in the groups with non-predegenerated nerve extracts, as well as fibrin, and was absent in the control group. CONCLUSION: Predegenerated nerve extracts, as well as BDNF, applied to injured optic nerves by means of connective tissue chambers, are able to induce retinal ganglion cell regeneration.

Tuberin and hamartin expression is reduced in the majority of subependymal giant cell astrocytomas in tuberous sclerosis complex consistent with a two-hit model of pathogenesis.

Subependymal giant cell astrocytomas are distinctive brain tumors that are seen only in tuberous sclerosis complex. Although histologically benign, they cause both moribidity and occasional mortality owing to progressive growth in some patients. Tuberous sclerosis complex is an autosomal dominant genetic disorder with a high sporadic case rate that is due to mutations in either of two genes, TSC1 and TSC2, encoding hamartin and tuberin, respectively. The pathogenesis of subependymal giant cell astrocytomas in tuberous sclerosis complex is uncertain. In this study, we examined the expression of tuberin and hamartin in subependymal giant cell astrocytomas from nine patients with tuberous sclerosis complex by immunohistochemistry with confocal microscopy. Loss of hamartin expression was seen in all subependymal giant cell astrocytomas, including five from patients with germline TSC2 mutations and two from patients with germline TSC1 mutations. The subependymal giant cell astrocytomas of six of nine patients had no expression of tuberin as well, whereas three patients retained some tuberin expression. Tuberin expression was seen in one patient with a TSC2 germline mutation and two patients whose mutational status was not determined. Overall, these data indicate a loss of both tuberin and hamartin expression in the subependymal giant cell astrocytomas of patients with both TSC1 and TSC2 mutations and are consistent with a two-hit disease pathogenesis model for the development of subependymal giant cell astrocytomas.

[Fusogens in the treatment of nervous system injury]. / Fuzogeny w terapii uszkodzen ukladu nerwowego.

In the paper a new method is presented of injured nerve fibres repair by means of the so-called fusogens. This entirely novel approach to the treatment of injuries of the central nervous system and peripheral nerves in humans may be feasible in a near future. Unquestionable advantages of these substances include their easy applicability and no undesirable side effects. What remains to be established is their mode of operation and precise therapeutic indications.

[Extracellular matrix metalloproteinases--perspectives of their use in medicine]. / Metaloproteinazy macierzy pozakomórkowej--perspektywy ich wykorzystania w medycynie.

Extracellular matrix turnover disturbances are implicated in many human diseases. Matrix Metalloproteinases (MMP) are believed to play a pivotal role in maintaining the intricate balance between extracellular matrix synthesis and degradation. These enzymes are active in the cleavage of many matrix proteins. There is evidence that matrix metalloproteinases activity changes in many pathological conditions, including inflammatory and degenerative disorders as well as tumour progression and metastases. This review focuses on the recent view on physiological and pathological function of MMPs. Authors aimed also to show the putative role of matrix metalloproteinases as a diagnostic tool in future medicine.

Surgical treatment of subependymal giant cell astrocytoma in tuberous sclerosis complex patients.

BACKGROUND: Subependymal giant cell astrocytoma is a brain tumor associated with tuberous sclerosis complex. There are two treatment options for subependymal giant cell astrocytomas: surgery or mammalian target of rapamycin inhibitor. The analysis of outcome of subependymal giant cell astrocytoma surgery may help characterize the patients who may benefit from pharmacotherapy. METHODS: Sixty-four subependymal giant cell astrocytoma surgeries in 57 tuberous sclerosis complex patients with at least a 12-month follow-up were included in the study. The tumor size, age of the patients, mutation in the TSC1 or TSC2 gene, indication for the surgery, and postsurgical complications were analyzed. RESULTS: The mean age of patients at surgery was 9.7 years. Mean follow-up after surgery was 63.7 months. Thirty-seven (57.8%) tumors were symptomatic and 27 (42.2%) were asymptomatic. Patients with TSC2 mutations developed subependymal giant cell astrocytoma at a significantly younger age than individuals with TSC1 mutations. Four patients (6.2% of all surgeries) died after surgery. Surgery-related complications were reported in 0%, 46%, 83%, 81%, and 67% of patients with tumors <2 cm, between 2 and 3 cm, between 3 and 4 cm, >4 cm, and bilateral subependymal giant cell astrocytomas, respectively, and were most common in children younger than 3 years of age. The most common complications included hemiparesis, hydrocephalus, hematoma, and cognitive decline. CONCLUSIONS: Our study indicates that subependymal giant cell astrocytoma surgery is associated with significant risk in individuals with bilateral subependymal giant cell astrocytomas, tumors bigger than 2 cm, and in children younger than 3 years of age. Therefore, tuberous sclerosis complex patients should be thoroughly screened for subependymal giant cell astrocytoma growth, and early treatment should be considered in selected patients.

Interleukin-1ß increases release of endothelin-1 and tumor necrosis factor as well as reactive oxygen species by peripheral leukocytes during experimental subarachnoid hemorrhage.

In the subarachnoid hemorrhage (SAH) blood mixes with cerebrospinal fluid, what starts immunoinflammatory processes - increased synthesis of proinflammatory cytokines, and formation of reactive oxygen species (ROS), resulting in pre-activation of different populations of peripheral leukocytes. Migration of leukocytes to the brain parenchyma through broken blood brain barrier may produce extra brain tissue injury besides of that resulting from SAH. We examined in adult rats the effect of interleukin-1ß (IL-1ß) neutralization on secretion of cytokines as well as production of ROS in the course of SAH. SAH was produced by injection of 150 µL of autologous arterial blood into cisterna magna. In 50% of animals, IL-1beta activity was inhibited by intracerebroventricular administration of anti-rat IL-1ß antibodies. Ninety minutes or 24 hrs following surgery, blood samples were drawn from the extraorbital plexus and centrifuged to obtain two leukocyte subpopulations - polymorphonuclear (PMN) and mononuclear (MN). The chemiluminescence, a hallmark of ROS synthesis, was measured in PMNs. In supernatants from MNs cultures, concentrations endothelin-1 (ET-1), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were assessed. SAH caused the increase ofn PMNs chemiluminescence as well as the increase of production of ET-1 and TNF-α by MNs but had no influence on IL-6 concentration. Neutralization of IL-1ß resulted in significant decrease of chemiluminescence as well as concentration of both ET-1 and TNF-α, while IL-6 concentration was increased. These revealed an important role of IL-1ß in the activation of peripheral leukocytes in the course of subarachnoid hemorrhage.