The role of ischemic neurodegeneration of the nodose ganglia on cardiac arrest after subarachnoid hemorrhage: An experimental study

New experimental finding of dangerous autonomic ganglia changes in cardiac injury following subarachnoid hemorrhage; a reciprocal culprit-victim relationship between the brain and heart

OBJECTIVE

The vagal, stellate, and cardiac ganglia cells changes following subarachnoid hemorrhage (SAH) may occur. This study aimed to investigate if there is any relation between vagal network/stellate ganglion and intrinsic cardiac ganglia insult following SAH.

MATERIALS AND METHODS

Twenty-six rabbits were used in this study. Animals were randomly divided as control (GI, n = 5); SHAM 0.75 cc of saline-injected (n = 5) and study with autologous 1.5 cc blood injection into their cisterna magna(GIII, n = 15). All animals were followed for three weeks and then decapitated. Their motor vagal nucleus, nodose, stellate, and intracardiac ganglion cells were estimated by stereological methods and compared statistically.

RESULTS

Numerical documents of heart-respiratory rates, vagal nerve- ICG, and stellate neuron densities as follows: 276 ± 32/min-22 ± 3/min-10.643 ± 1.129/mm3-4 ± 1/mm3-12 ± 3/mm3 and 2 ± 1/cm3 in the control group; 221 ± 22/min-16 ± 4/min-8.699 ± 976/mm3-24 ± 9/mm3-103 ± 32/mm3 and 11 ± 3/cm3 in the SHAM group; and 191 ± 23/min-17 ± 4/min-9.719 ± 932/mm3-124 ± 31/mm3-1.542 ± 162/mm3 and 32 ± 9/cm3 in the SAH (study) group. The animals with burned neuro-cardiac web had more neurons of stellate ganglia and a less normal neuron density of nodose ganglia (p < 0.005).

CONCLUSION

Sypathico-parasympathetic imbalance induced vagal nerve-ICG disruption following SAH could be named as Burned Neurocardiac Web syndrome in contrast to broken heart because ICG/parasympathetic network degeneration could not be detected in classic broken heart syndrome. It was noted that cardiac ganglion degeneration is more prominent in animals' severe degenerated neuron density of nodose ganglia. We concluded that the cardiac ganglia network knitted with vagal-sympathetic-somatosensitive fibers has an important in heart function following SAH. The neurodegeneration of the cardiac may occur in SAH, and cause sudden death.Graphical abstract[Formula: see text].

Assessment of oxidative/nitrosative stress and antioxidant capacity in children with epilepsy

Background: The underlying pathophysiological mechanisms in epilepsy, one of the most common neurological diseases, are still unknown. Oxidative/nitrosative stress is considered a possible mechanism involved in epileptogenesis. The production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) is involved in the pathogenesis of signal regulation, cellular damage and central nervous system conditions in living organisms. In this study, we aimed to compare peoxynitrite (ONOO-), a marker of nitrosative stress, total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI) and 8-hydroxy-2-deoxyguanosine (8-OHdG), DNA damage marker, levels in epileptic patients receiving monotherapy and polytherapy with the healthy control group.Methods: The study included 120 patients with diagnosis of epilepsy and 40 healthy volunteers as controls. The TOS, TAS, OSI, ONOO- and 8-OHdG were studied in all groups.Results: The study group included 30 girls (50%) and 30 boys (50%) receiving monotherapy and 31 girls (51.7%) and boys 49.3%) receiving polytherapy while control group included 19 girls (47.5%) and 21 boys (52.5%). The TOS and OSI values were found to be significantly higher in polytherapy group when compared to monotherapy and control groups). The ONOO- values were found to be significantly lower in polytherapy group when compared to monotherapy and control groups. In addition, ONOO- values were found to be higher in monotherapy group than controls. There was no significant difference in 8-OHdG values between the groups.Conclusions: Significant increases were observed in TOS and OSI parameters in polytherapy group when compared to monotherapy and control groups, suggesting that antiepileptic treatment enhances oxidative stress. Lack of significant difference in 8-OHdG suggested that the treatment is effective in patients and that no DNA damage occurred yet.

New Evidence for Regulatory Role of Trigeminal Ganglion on the Intraocular Pressure Following Subarachnoid Hemorrhage

BACKGROUND

 Increased intraocular pressure (IOP) likely secondary to an activated oculo-trigeminal reflex network is an important issue following subarachnoid hemorrhage (SAH). The relationship between the IOP and trigeminal ganglion (TGG) following experimental SAH was investigated in this study.

METHODS

 Twenty-three rabbits were used in this study. Five rabbits (n = 5) were used as the control group, another 5 as the sham group (n = 5), and the remaining 13 (n = 13) as the study group. The study group was further divided into two groups of animals with mild (n = 6) and severe (n = 7) TGG degeneration. The IOP values were recorded. After 2 weeks, the animals were decapitated. The mean degenerated neuron density of TGGs was estimated by stereological methods and analyzed statistically.

RESULTS

 The average IOP values were 11.85, 14.12, and 21.45 mm Hg in the control (n = 5), sham (n = 5), and study (n = 13) groups, respectively. The mean degenerated neuron density was 34, 237, and 3,165 mm3 in the control, sham, and study groups, respectively.

CONCLUSION

 According to the findings of this study, the experimental SAH leads to changes in IOP by affecting the TGG. By predicting and preventing IOP elevation in the setting of SAH, our findings will shed light on secondary sequelae such as glaucoma and irreversible blindness.

Overlooked evidence for transmission deficit of pupillary light reflex can be secondary to trigeminal nerve ganglion degeneration following subarachnoid hemorrhage; preliminary experimental study

OBJECTIVE

Although the effect of oculomotor and cervical sympathetic networks on pupil diameter is well known; the effect of the trigeminal nerve on pupil diameter has not been investigated yet. This subject was investigated.

MATERIALS AND METHODS

Five of 23 rabbits were used as a control group (GI; n = 5); 0.5 ccs saline solution into cisterna magna injected animals used as SHAM (GII; n = 5); autologous blood injected to produce SAH used as the study group (GIII; n = 13) and followed up three weeks. Light-stimulated pupil diameters were measured with an ocular tomography device before, middle, and at the end of the experiment. Considering the sclera area/pupil area ratio index (PRI) as the pupillary reaction area, we used this equation for the pupil's rush to light. Degenerated neuron densities of trigeminal ganglia and pupil diameters compared with the Mann-Whitney U test.

RESULTS

The PRI, degenerated neuron density of trigeminal ganglia (n/mm3) were: (2.034 ± 0.301)/(13 ± 3) in GI; (1.678 ± 0.211)/(46 ± 9) in GII; and (0.941 ± 0.136)/(112 ± 21) in GIII. P-values between groups as: p < 0.005 in GI/GII; p < 0.0001 in GII/GIII and p < 0.00001 in GI/GIII.

CONCLUSION

Light stimulates the cornea which is innervated by the trigeminal nerves. This experimental study indicates that the pupil remains mydriatic as the cornea is damaged by trigeminal ischemia following SAH and blocks the light flow.

New histopathological evidence for the relationship between hydromyelia and hydrocephalus following subarachnoid hemorrhage: An experimental study

Objectives

Subarachnoid hemorrhage (SAH) is a serious pathology with a high death and morbidity rate. There can be a relationship between hydromyelia and hydrocephalus following SAH; however, this subject has not been well investigated.

Materials and Methods

Twenty-four rabbits (3 ± 0.4 years old; 4.4 ± 0.5 kg) were used in this study. Five of them were used as the control, and five of them as the SHAM group. The remaining animals (n = 14) had been used as the study group. The central canal volume values at the C1-C2 levels, ependymal cells, numbers of central canal surfaces, and Evans index values of the lateral ventricles were assessed and compared.

Results

Choroid plexus edema and increased water vesicles were observed in animals with central canal dilatation. The Evans index of the brain ventricles was 0.33 ± 0.05, the mean volume of the central canal was 1.431 ± 0.043 mm3, and ependymal cells density was 5.420 ± 879/mm2 in the control group animals (n = 5); 0.35 ± 0.17, 1.190 ± 0.114 mm3, and 4.135 ± 612/mm2 in the SHAM group animals (n = 5); and 0.44 ± 0.68, 1.814 ± 0.139 mm3, and 2.512 ± 11/mm2 in the study group (n = 14). The relationship between the Evans index values, the central canal volumes, and degenerated ependymal cell densities was statistically significant (P < 0.05).

Conclusions

This study showed that hydromyelia occurs following SAH-induced experimental hydrocephalus. Desquamation of ependymal cells and increased cerebrospinal fluid secretion may be responsible factors in the development of hydromyelia.

Cardiac vagal afferent neurotransmission in health and disease: review and knowledge gaps

The meticulous control of cardiac sympathetic and parasympathetic tone regulates all facets of cardiac function. This precise calibration of cardiac efferent innervation is dependent on sensory information that is relayed from the heart to the central nervous system. The vagus nerve, which contains vagal cardiac afferent fibers, carries sensory information to the brainstem. Vagal afferent signaling has been predominantly shown to increase parasympathetic efferent response and vagal tone. However, cardiac vagal afferent signaling appears to change after cardiac injury, though much remains unknown. Even though subsequent cardiac autonomic imbalance is characterized by sympathoexcitation and parasympathetic dysfunction, it remains unclear if, and to what extent, vagal afferent dysfunction is involved in the development of vagal withdrawal. This review aims to summarize the current understanding of cardiac vagal afferent signaling under in health and in the setting of cardiovascular disease, especially after myocardial infarction, and to highlight the knowledge gaps that remain to be addressed.

Retrograde dye perfusion of the proximal aorta - A postmortem technical study

Introduction

Multiple cardiovascular conditions can lead to unexpected fatality, which is defined as sudden cardiac death. One of these potentially underlying conditions is aortic regurgitation, which can be caused by discrete changes of the geometry of the proximal aorta. To analyze aortic valve competency and furthermore to elucidate underlying pathological alterations of the coronary arteries and the vasa vasorum a perfusion method to simulate a diastolic state was designed.

Material and methods

A postmortem approach with retrograde perfusion of the ascending aorta with methylene blue was applied to three bodies. The procedure comprised cannulation of the brachiocephalic trunk, clamping of the aortic arch between brachiocephalic trunk and left carotid artery, infusion of 250 ml of methylene blue, and optical clearing of the superficial tissue layers after perfusion. Organs were examined directly following perfusion and after optical clearing.

Results

Assessment and visualization of aortic valve competency and the vasa vasorum were possible in all three instances. Visualization of the coronary perfusion was impaired by postmortem thrombus formation. Optical clearing did not provide additional information.

Discussion

The method presented here is a time- and cost-efficient way of visualizing aortic valve competency and the vasa vasorum. The visualization of the vasa vasorum highlights the potential of this method in basic research on diseases of the great arteries and coronaries. However, for a time-efficient functional analysis of the coronaries, other methods must be applied.

Convergent cardiorespiratory neurons represent a significant portion of cardiac and respiratory neurons in the vagal ganglia

Significant cardiorespiratory coordination is required to maintain physiological function in health and disease. Sensory neuronal “cross-talk” between the heart and the lungs is required for synchronous regulation of normal cardiopulmonary function and is most likely mediated by the convergence of sensory neural pathways present in the autonomic ganglia. Using neurotracer approaches with appropriate negative control experiments in a mouse model, presence of cardiorespiratory neurons in the vagal (nodose) ganglia are demonstrated. Furthermore, we found that convergent neurons represent nearly 50% of all cardiac neurons and approximately 35% of all respiratory neurons. The current findings demonstrate a pre-existing neuronal substrate linking cardiorespiratory neurotransmission in the vagal ganglia, and a potentially important link for cardiopulmonary cross-sensitization, which may play an important role in the observed manifestations of cardiopulmonary diseases.

The calcimimetic R-568 attenuates subarachnoid hemorrhage-induced vasospasm through PI3K/Akt/eNOS signaling pathway in the rat model

Cerebral vasospasm (CVS) causes mortality and morbidity in patients after subarachnoid hemorrhage (SAH). The mechanism and adequate treatment of CVS are still elusive. R-568 is a calcimimetic agent known to exert a vasodilating effect. However, there is no report on its vasodilator effect against SAH-induced vasospasm. In the present study, we investigated the therapeutic effect of R-568 on the SAH-induced CVS model in rats. Seventy-two adult male Sprague-Dawley rats were divided into 8 groups: sham surgery; SAH only; SAH + Vehicle, SAH + R-568; SAH + R-568 + Wortmannin (the PI3K inhibitor); SAH + Wortmannin; SAH + R-568 + Calhex-231 (a calcilytic agent); SAH + Calhex-231. SAH was induced by blood (0.3 mL) given by intracisternal injection. R-568 (20 µM) was administered intracisternal immediately prior to experimental SAH. Basilar arteries (BAs) were obtained to evaluate PI3K/Akt/eNOS pathway (immunoblotting) and morphological changes 48 h after SAH. Perimeters of BAs were decreased by 24.1% in the SAH group compared to the control group and the wall thickness was increased by 75.3%. With R-568 treatment, those percentages were 9.6% and 29.6%, respectively, indicating that vasospasm was considerably improved when compared with the SAH group (P < 0.001 in both). While p-PI3K/PI3K and p-Akt/Akt ratio and eNOS protein expression were markedly decreased in the SAH rats, treatment with R-568 resulted in a significant increase in these levels. The beneficial effects of R-568 were partially blocked in the presence of Calhex-231 and completely blocked in the presence of Wortmannin. Herein, we found that treatment with R-568 would attenuate SAH-induced CVS through the PI3K/Akt/eNOS pathway and demonstrate therapeutic promise in CVS treatment following SAH.

Important interaction between urethral taste bud-like structures and Onuf's nucleus following spinal subarachnoid hemorrhage: A hypothesis for the mechanism of dysorgasmia

BACKGROUND

We previously postulated that orgasmic sensation may occur through recently discovered genital taste bud-like structures. The interaction between the pudendal nerve and Onuf's nucleus may be important for developing orgasmic information. The study aims to investigate whether ischemic damage to Onuf's nucleus-pudendal network following spinal subarachnoid hemorrhage (SAH) causes taste bud degeneration or not.

METHODS

The study was conducted on 22 fertile male rabbits who were divided into three groups: control (GI; n=5), SHAM (GII; n=5) and study (GIII; n=12). Isotonic solution, .7cm³, for the SHAM, and .7cm³ homologous blood was injected into spinal subarachnoid spaces at S2 level of the study group. Two weeks later, Onuf's nucleus, pudendal ganglia and the taste bud-like structures of the penile urethra were examined histopathologically. Degenerated neuron densities of Onuf's nucleus, pudendal ganglia and atrophic taste bud-like structures were estimated per mm³ and the results analyzed statistically.

RESULTS

The mean degenerated neuron densities of taste bud-like structures, Onuf's nucleus and pudendal ganglia were estimated as 2±1/mm³, 5±1/mm³, 6±2/mm³ in GI; 12±4/mm³, 35±9/mm³, 188±31/mm³, in GII and 41±8/mm³, 215±37/mm³, 1321±78/mm³, in GIII. Spinal SAH induced neurodegeneration in Onuf's nucleus, pudendal ganglia and taste bud atrophy was significantly different between GI/GII (p<.005); GII/GIII (p<.0005) and GI/GIII (p<.0001).

CONCLUSION

Ischemic neuronal degenerations of Onuf's nucleus and pudendal ganglia following spinal SAH lead to genital taste bud-like structure atrophy. This mechanism may be responsible for sexual anhedonia and sterility in cases with spinal cord injury, which has not been documented so far. More studies are needed.

First definition of burned choroid plexus in acidic cerebrospinal fluid-filled brain ventricles during subarachnoid hemorrhage: Experimental study

Blood and cerebrospinal fluid (CSF) acidosis is the most troubling complication in subarachnoid hemorrhage (SAH) if carotid body (CB) networks are disrupted. However, histopathological examination of the choroid plexus (CP) in acidic CSF has not been evaluated so far. In this study, we aimed to investigate the CP in acidic CSF following SAH. Twenty-eight rabbits were used. Five rabbits were used to analyze CB network (control group; n = 5); seven rabbits were injected 1 mL of saline (Sham group; n = 7); and the rest 16 rabbits were given 1 mL of autologous arterial blood inject into the cisterna magna to create SAH (SAH group; n = 16). Blood and CSF pH values were recorded before/during/after the experimental procedures. Nuclear darkening, cellular shrinkage and pyknosis suggested the presence of apoptosis of epithelial cells of CP. The densities of normal and degenerated epithelial cells of CPs were estimated using stereological methods. The relationship between the pH values and degenerated epithelial cell densities of CPs were statistically compared by Mann-Whitney U-test. The pH values of blood were estimated as 7.359 ± 0.039 in the control group, 7.318 ± 0.062 in the Sham group, 7.23 ± 0.013 in the SAH group. CSF pH values were 7.313 ± 0.028 in the control group, 7.296 ± 0.045 in the Sham group, and 7.224 ± 0.012 in the SAH group. Degenerated epithelial cell density of CP was 25 ± 7 in the control group, 226 ± 64 in the Sham group, and 2115 ± 635 in the SAH group. There was a considerable link between CSF pH values and degenerated epithelial cells of CP (P < 0.0001). This study shows that CB insult causes acidosis of CSF as well as cellular degeneration of CP during SAH. This is the first description of this in the literature.

Predestinating Role of Cardiac Ganglia on Heart Life Expectancy in Rabbits After Brain Death Following Subarachnoid Hemorrhage: An Experimental Study

BACKGROUND

Cardiac ganglia are rechargeable batteries of the heart. The essential role of cardiac ganglia on cardiac life expectancy has not been examined following brain death. The aim of this study was to determine cardiac ganglia numbers and neuron density following subarachnoid hemorrhage (SAH).

METHODS

Twenty-five hybrid rabbits were grouped as control (n = 5), sham (n = 5), and SAH (n = 15). The SAH groups' animals were subjected to injections of lethal dose of 2.00 cc autologous blood into their cisterna magna until linear EEG was obtained. The hearts of all animals were extracted following intracardiac formalin injection and examined. Cardiac ganglia and normal/degenerated neuron densities of cardiac neurons were recorded.

RESULTS

The mean volume of normal neuron density of ganglia was 6.980 ± 830/mm³, and the degenerated neuron density of ganglia was 3 ± 1/mm³ in the control group, 6134 ± 712/mm³; 23 ± 9/mm³ in the sham group, 3456 ± 589; 1161 ± 72/mm³ in the surviving group; and 1734 ± 341/mm³, 4259 ± 865/mm³ in the dead animals in the SAH group. The algebraic results of heart work capacity (Wh) were estimated as 1375 ± 210 Wh in the control group, 1036 ± 225 in the sham group, 800 ± 110 Wh in the surviving group, and < 100 ± 20 in the dead animals in the SAH group. Degenerated cardiac neuron density/Wh correlation is statistically meaningful between the dead in the SAH group versus the SAH-surviving, sham, and control groups (P < .0005).

CONCLUSIONS

Normal cardiac ganglia numbers and/or cardiac ganglia neuron density may be related to cardiac survival following brain death after subarachnoid hemorrhage.

Disruption of the network between Onuf's nucleus and myenteric ganglia, and developing Hirschsprung-like disease following spinal subarachnoid haemorrhage: an experimental study

Purpose/Aim of the study: Auerbach/Meissner network of lower abdominopelvic organs managed by parasympathetic nerve fibres of lumbosacral roots arising from Onuf's nucleus located in conus medullaris. Aim of this study is to evaluate if there is any relationship between Onuf's nucleus ischemia and Auerbach/Meissner network degeneration following spinal subarachnoid haemorrhage (SAH). Materials and Methods: Study was conducted on 24 male rabbits included control (Group I, n = 5), serum saline-SHAM (Group II, n = 5), and spinal SAH (Group III, n = 14) groups. Spinal SAH performed by injecting homologous blood into subarachnoid space at Th₁₂-L₄ level and followed three weeks. Live and degenerated neuron densities of Onuf's nucleus, Auerbach and Meissner ganglia (n/mm³) were determined by Stereological methods. Results: The mean degenerated neuron density of Onuf's nucleus was significantly higher in Group III than in Groups I-II (152 ± 26, 2 ± 1 and 5 ± 2/mm³ respectively, p < 0.005). The degenerated neuron density of Auerbach's ganglia was significantly higher in Group III than in Groups I-II (365 ± 112, 3 ± 1 and 9 ± 3/mm³ respectively, p < 0.005). The degenerated neuron density of Meissner's ganglia was significantly higher in Group III than in Groups I-II (413 ± 132, 2 ± 1 and 11 ± 4/mm³ respectively, p < 0.005). Conclusions: Onuf's nucleus pathologies should be considered as Auerbach/Meissner ganglia degeneration and also related Hirschsprung-like diseases in the future.

A new described mechanisms of intestinal glandular atrophy induced by vagal nerve/Auerbach network degeneration following subarachnoid hemorrhage: The first experimental study

Stress ulcers is a trouble complication of subarachnoid hemorrhage (SAH). Although gastrointestinal ulcerations may be attributed to increased HCL secretion in SAH; the exact mechanism of that complication has not been investigated definitively. We studied if vagal network degeneration may cause intestinal atrophy following SAH. Study was conducted on 25 rabbits, with 5 control group (Group-A), 5 SHAM group (Group-B), and 15 SAH group via injection of autologue blood to cisterna magna. Seven animals followed for seven days (Early Decapitated-Group-C) and eight animals followed 21 days (Late Decapitated-Group-D). The vagal nodosal ganglia (NGs), Auerbach plexuses and goblet cells of duodenums were examined by current stereological methods and compared statistically. The mean numbers of degenerated axon density/mm² of gastric branches of vagal nerves was 8 ± 2, 34 ± 11, 189 ± 49 and 322 ± 81 in the Group A, B, C, and D respectively. The mean numbers of degenerated neuron density/mm³ of NGs was 5 ± 2, 54 ± 7, 691 ± 87 and 2930 ± 410 in the Group A, B, C, and D respectively. The mean numbers of degenerated Auerbach neurons 2 ± 1, 4 ± 1, 12 ± 3 and 27 ± 5/mm³ in the Group A, B, C, and D respectively. The mean numbers of degenerated goblet cells/mm³ were 4.3 ± 1.02, 11.5 ± 0.26, 143 ± 26 and 937 ± 65 Group A, B, C, and D respectively. Statistical analysis showed that vagal network ischemia could cause intestinal bleeding and so atrophy in SAH progression. Statistical analyses of groups were; Group-D/Group-A < 0.001, Group-D/Group-B < 0.005, Group-C/Group-A < 0.005. Undiscovered effect of ischemic vagal network injuries should be regarded as a major cause of stress ulcerations following SAH which has not been mentioned in the literature.

First report of important causal relationship between the Adamkiewicz artery vasospasm and dorsal root ganglion cell degeneration in spinal subarachnoid hemorrhage: An experimental study using a rabbit model

Background:

The blood supply of the lower spinal cord is heavily dependent on the artery of Adamkiewicz. The goal of this study was to elucidate the effects of lumbar subarachnoid hemorrhage (SAH) on the lumbar 4 dorsal root ganglion (L4DRG) cells secondary to Adamkiewicz artery (AKA) vasospasm.

Materials and Methods:

This study was conducted on 20 rabbits, which were randomly divided into three groups: Spinal SAH (n = 8), serum saline (SS) (SS; n = 6) and control (n = 6) groups. Experimental spinal SAH was performed. After 20 days, volume values of AKA and neuron density of L4DRG were analyzed.

Results:

The mean alive neuron density of the L4DRG was 15420 ± 1240/mm³ and degenerated neuron density was 1045 ± 260/mm³ in the control group. Whereas, the density of living and degenerated neurons density were 12930 ± 1060/mm³ and 1365 ± 480/mm³ in serum saline (SS), 9845 ± 1028/mm³ and 4560 ± 1340/mm³ in the SAH group. The mean volume of imaginary AKAs was estimated as 1,250 ± 0,310 mm³ in the control group and 1,030 ± 0,240 mm³ in the SF group and 0,910 ± 0,170 mm³ in SAH group. Volume reduction of the AKAs and neuron density L4DRG were significantly different between the SAH and other two groups (P < 0.05).

Conclusion:

Decreased volume of the lumen of the artery of Adamkiewicz was observed in animals with SAH compared with controls. Increased degeneration the L4 dorsal root ganglion in animals with SAH was also noted. Our findings will aid in the planning of future experimental studies and determining the clinical relevance on such studies.

Sudden death and cervical spine: A new contribution to pathogenesis for sudden death in critical care unit from subarachnoid hemorrhage; first report - An experimental study

Context:

Sudden death from subarachnoid hemorrhage (SAH) is not uncommon.

Aims:

The goal of this study is to elucidate the effect of the cervical spinal roots and the related dorsal root ganglions (DRGs) on cardiorespiratory arrest following SAH.

Settings and Design:

This was an experimental study conducted on rabbits.

Materials and Methods:

This study was conducted on 22 rabbits which were randomly divided into three groups: control (n = 5), physiologic serum saline (SS; n = 6), SAH groups (n = 11). Experimental SAH was performed. Seven of 11 rabbits with SAH died within the first 2 weeks. After 20 days, other animals were sacrificed. The anterior spinal arteries, arteriae nervorum of cervical nerve roots (C6–C8), DRGs, and lungs were histopathologically examined and estimated stereologically.

Statistical Analysis Used:

Statistical analysis was performed using the PASW Statistics 18.0 for Windows (SPSS Inc., Chicago, Illinois, USA). Intergroup differences were assessed using a one-way ANOVA. The statistical significance was set at P < 0.05.

Results:

In the SAH group, histopathologically, severe anterior spinal artery (ASA) and arteriae nervorum vasospasm, axonal and neuronal degeneration, and neuronal apoptosis were observed. Vasospasm of ASA did not occur in the SS and control groups. There was a statistically significant increase in the degenerated neuron density in the SAH group as compared to the control and SS groups (P < 0.05). Cardiorespiratory disturbances, arrest, and lung edema more commonly developed in animals in the SAH group.

Conclusion:

We noticed interestingly that C6–C8 DRG degenerations were secondary to the vasospasm of ASA, following SAH. Cardiorespiratory disturbances or arrest can be explained with these mechanisms.

Unraveling of the Effect of Nodose Ganglion Degeneration on the Coronary Artery Vasospasm After Subarachnoid Hemorrhage: An Experimental Study

BACKGROUND

Cardiac arrest is a major life-threatening complication of subarachnoid hemorrhage (SAH). Although medullary cardiocirculatuar center injury and central sympathetic overactivity have been suspected of initiating coronary artery spasm-induced cardiac arrest, we aimed to elucidate the effects of vagal ischemia at the brainstem on coronary vasospasm and sudden death in SAH.

METHODS

Twenty-six rabbits were randomly divided into 3 groups. Control (n = 5); SHAM (n = 8), and SAH group (n = 13). Experimental SAH was applied by injecting homologous blood into the cisterna magna, and the SHAM group was injected with isotonic saline solution also in the cisterna magna., Twenty-one days after the injection, histopathologic changes of the neuron density of nodose ganglia, the vasospasm index values of the coronary arteries, and the electrocardiographic events were analyzed.

RESULTS

Increased vasospasm index of the coronary arteries and degenerated neuron density of nodose ganglion were significantly different between animals with SAH, control, and SHAM groups (P < 0.005). If neurons of the nodose ganglia are lesioned due to ischemic insult during SAH, the heart rhythm regulation by vagus afferent reflexes is disturbed.

CONCLUSIONS

We found that there is causal relationship between nodose ganglion degeneration and coronary vasospasm. Our finding could be the reason that many cardiac events occur in patients with SAH. Vagal pathway paralysis induced by indirect sympathetic overactivity may trigger coronary vasospasm and heart rhythm disturbances. Our findings will aid in the planning of future experimental studies and in determining the clinical relevance of such studies.

The impact of L5 dorsal root ganglion degeneration and Adamkiewicz artery vasospasm on descending colon dilatation following spinal subarachnoid hemorrhage: An experimental study; first report

CONTEXT

Somato-sensitive innervation of bowels are maintained by lower segments of spinal cord and the blood supply of the lower spinal cord is heavily dependent on Adamkiewicz artery. Although bowel problems are sometimes seen in subarachnoid hemorrhage neither Adamkiewicz artery spasm nor spinal cord ischemia has not been elucidated as a cause of bowel dilatation so far.

AIMS

The goal of this study was to study the effects Adamkiewicz artery (AKA) vasospasm in lumbar subarachnoid hemorrhage (SAH) on bowel dilatation severity.

SETTINGS AND DESIGN

An experimental rabbit study.

MATERIALS AND METHODS

The study was conducted on 25 rabbits, which were randomly divided into three groups: Spinal SAH (N = 13), serum saline (SS) (SS; N = 7) and control (N = 5) groups. Experimental spinal SAH was performed. After 21 days, volume values of descending parts of large bowels and degenerated neuron density of L5DRG were analyzed.

STATISTICAL ANALYSIS USED

Statistical analysis was performed using the PASW Statistics 18.0 for Windows (SPSS Inc., Chicago, Illinois). Two-tailed t-test and Mann-Whitney U-tests were used. The statistical significance was set at P < 0.05.

RESULTS

The mean volume of imaginary descending colons was estimated as 93 ± 12 cm(3) in the control group and 121 ± 26 cm(3) in the SS group and 176 ± 49 cm(3) in SAH group. Volume augmentations of the descending colons and degenerated neuron density L5DRG were significantly different between the SAH and other two groups (P < 0.05).

CONCLUSION

An inverse relationship between the living neuronal density of the L5DRG and the volume of imaginary descending colon values was occurred. Our findings will aid in the planning of future experimental studies and determining the clinical relevance on such studies.

Gastric vagal motoneuron function is maintained following experimental spinal cord injury

BACKGROUND

Clinical reports indicate that spinal cord injury (SCI) initiates profound gastric dysfunction. Gastric reflexes involve stimulation of sensory vagal fibers, which engage brainstem circuits that modulate efferent output back to the stomach, thereby completing the vago-vagal reflex. Our recent studies in a rodent model of experimental high thoracic (T3-) SCI suggest that reduced vagal afferent sensitivity to gastrointestinal (GI) stimuli may be responsible for diminished gastric function. Nevertheless, derangements in efferent signals from the dorsal motor nucleus of the vagus (DMV) to the stomach may also account for reduced motility.

METHODS

We assessed the anatomical, neurophysiological, and functional integrity of gastric-projecting DMV neurons in T3-SCI rats using: (i) retrograde labeling of gastric-projecting DMV neurons; (ii) whole cell recordings from gastric-projecting neurons of the DMV; and, (iii) in vivo measurements of gastric contractions following unilateral microinjection of thyrotropin-releasing hormone (TRH) into the DMV.

KEY RESULTS

Immunohistochemical analysis of gastric-projecting DMV neurons demonstrated no difference between control and T3-SCI rats. Whole cell in vitro recordings showed no alteration in DMV membrane properties and the neuronal morphology of these same, neurobiotin-labeled, DMV neurons were unchanged after T3-SCI with regard to cell size and dendritic arborization. Central microinjection of TRH induced a significant facilitation of gastric contractions in both control and T3-SCI rats and there were no significant dose-dependent differences between groups.

CONCLUSIONS & INFERENCES

Our data suggest that the acute, 3 day to 1 week post-SCI, dysfunction of vagally mediated gastric reflexes do not include derangements in the efferent DMV motoneurons.

The single and double blood injection rabbit subarachnoid hemorrhage model

Over the past 30 years, the rabbit subarachnoid hemorrhage model (SAH) has been used for investigating the post-hemorrhage pathology, especially with respect to understanding of the mechanisms of cerebral vasospasm. However, the molecular mechanisms of cerebral vasospasm remain to be elucidated. Furthermore, it is not clear whether the rabbit SAH model is suitable for the investigation of pathological conditions other than cerebral vasospasm, such as early brain injury. Therefore, the properties of the rabbit SAH model need to be validated, and the reasons for using the rabbit should be clarified. This review explores the settings and technical issues of establishing a rabbit cisterna magna single and double blood injection SAH model and discusses the characteristics and feasibilities of the models.

The harmful effects of subarachnoid hemorrhage on extracerebral organs

Subarachnoid hemorrhage (SAH) is a devastating neurological disorder. Patients with aneurysmal SAH develop secondary complications that are important causes of morbidity and mortality. Aside from secondary neurological injuries, SAH has been associated with nonneurologic medical complications, such as neurocardiogenic injury, neurogenic pulmonary edema, hyperglycemia, and electrolyte imbalance, of which cardiac and pulmonary complications are most common. The related mechanisms include activation of the sympathetic nervous system, release of catecholamines and other hormones, and inflammatory responses. Extracerebral complications are directly related to the severity of SAH-induced brain injury and indicate the clinical outcome in patients. This review provides an overview of the extracerebral complications after SAH. We also aim to describe the manifestations, underlying mechanisms, and the effects of those extracerebral complications on outcome following SAH.

Changes in number of water-filled vesicles of choroid plexus in early and late phase of experimental rabbit subarachnoid hemorrhage model: the role of petrous ganglion of glossopharyngeal nerve

BACKGROUND

Cerebrospinal fluid (CSF) secretion may be increased in the early phases of subarachnoid hemorrhage (SAH), possibly via ischemic glossopharyngeal nerve discharges, and decreased due to glossopharyngeal nerve degeneration in the late phase of SAH; but this reflex pathway has not been definitively investigated. We studied the relationship between petrous ganglion of the glossopharyngeal nerve (GPN) and water vesicles of the choroid plexus (CP) in the early and late phases of SAH.

METHODS

This study was conducted on 30 rabbits, divided into four groups, with five rabbits in the control group (group I), five rabbits in the sham group (Group II), and 20 rabbits in the SAH group. In the SAH group, five of the animals were decapitated after 4 days of cisternal blood injections (Group III), and the other 15 animals were decapitated after 20 days of injections (Group IV). The Petrous Ganglia and CPs of lateral ventricles were removed and stained for stereological analysis.

RESULTS

The mean number of follicles per cubic millimeter was 5.3 ± 1.2 the in control group (Group I), 4.5 ± 0.9 in the sham group (Group II), 16.60 ± 3.77 the in early decapitated group (Group III), and 4.30 ± 0.84 in the late decapitated group (Group IV). The mean number of degenerated neuron density of petrous ganglions was 6 ± 2, 50 ± 6, 742 ± 96, and 2.420 ± 350 in the control (Group I), sham (Group II), early decapitated (Group III), and late decapitated group (Group IV), respectively. The mean number of water vesicles was statistically different after SAH between the early decapitated group (group III) and the late decapitated group (group IV) (P < 0.05).

CONCLUSIONS

We studied the relationship between petrous ganglion cells of the GPN and water vesicles of CP in the early and late phases of SAH, and found that CP vesicles are increased in the early phase of SAH due to irritation of GPN, and decreased in the late phase due to ischemic insult of the petrous ganglion and parasympathetic innervation of the CP.

Toward changing of the pathophysiologic basis of acute hydrocephalus after subarachnoid hemorrhage: a preliminary experimental study

BACKGROUND

Acute hydrocephalus (ventricular enlargement within 72 hours) is a common complication in patients with aneurysmal subarachnoid hemorrhage (SAH). Cerebrospinal fluid (CSF) secretion may be increased in the early phases of SAH, but it has not been proved definitively. We studied the histologic features of choroid plexus (CP) in the early and late phases of SAH.

METHODS

This study was conducted on 20 rabbits, with 5 rabbits in the control group, 5 rabbits in the sham group, and 10 rabbits in the SAH group. In the SAH group, five of the animals were decapitated after 2 days of cisternal blood injections, and the other five animals were decapitated after 14 days of injections. The CP of lateral ventricles were obtained from coronary sections of brains at the level of the temporal horns of the lateral ventricles. Sections were stained with hematoxylin and eosin and Masson trichrome for SAH-related damage and examined stereologically to discern water-filled vesicles, which were counted. Sections were compared statistically.

RESULTS

The mean numbers of water vesicles were different after SAH between the early decapitated group (group III) and the late decapitated group (group IV). The mean numbers of water vesicles were 2.80 (± 0.05) in the control group (group I), 2.76 (± 0.02) in the sham group (group II), 14.68 (± 0.06) in the early decapitated group (group III), and 4.78 (± 0.13) in the late decapitated group (group IV). Total number of fluid-filled vesicles of CP was also assessed stereologically; the total numbers were 840 (± 16) in group I, 828 (± 7) in group II, 4404 (± 19) in group III, and 1434 (± 41) in group IV. The numbers of water-filled cisterns were significantly increased in the early phases of SAH (P < 0.05).

CONCLUSIONS

In SAH with aneurysm rupture, increased CSF secretion seems to be triggered by hemorrhage in the early phase, but it is not possible in the late phase because of CP degeneration. In the early phase of hemorrhage, CSF secretion may be stimulated by the irritant receptor glossopharyngeal and vagal nerve endings, which innervate the healthy CP epithelium and arteries. Our findings may be accepted as being causative. It is likewise possible that CSF blockage per se leads to hydrocephalus, and the morphologic changes are sequelae that occur later in the course of disease. This is the first study to show the water vesicles of CP as a causative factor in the development of acute hydrocephalus after SAH.

Recombinant high-mobility group box 1 protein (HMGB-1) promotes myeloid differentiation primary response protein 88 (Myd88) upregulation in mouse primary cortical neurons

Myeloid differentiation primary response protein 88 (Myd88) is a vital factor for inflammation and immunity, and high-mobility group box 1 protein (HMGB-1) can be released from neurons after injury and may contribute to the initial stages of inflammatory response. Therefore, the current study was intended to investigate the expression of Myd88 in cultured neurons following recombinant HMGB-1 (rHMGB-1) addition and to clarify the potential role of Myd88 after neuron injury in vitro. The cultured neurons were randomly divided into six groups: control group and rHMGB-1 groups at hours 1, 6, 12, 24, and 48. The cultured neurons in rHMGB-1 groups were subjected to rHMGB-1 addition. The expression of Myd88 was assessed by quantitative real-time polymerase chain reaction (PCR), Western blotting and immunofluorescence, and nuclear factor kappa B (NF-κB) DNA-binding activity was detected by electrophoretic mobility shift assay, and the levels of tumor necrosis factor-α (TNF-α) and interleukin 1β (IL-1β) were measured by quantitative real-time PCR. The elevated mRNA and protein levels of Myd88, peaking at 24 h, were detected after rHMGB-1 addition. NF-κB, TNF-α, and IL-1β also ascended significantly after rHMGB-1 addition. Interestingly, Myd88 increasingly expressed in a parallel time course to the upregulation of NF-κB, TNF-α, and IL-1β. These findings indicated a possible role of Myd88 in the inflammatory response after neuron injury, and might provide an attractive therapeutic approach of targeting the Myd88 cascade to achieve better outcomes for patients with central nervous system injury.