New Histopathologic Evidence for the Parasympathetic Innervation of the Kidney and the Mechanism of Hypertension Following Subarachnoid Hemorrhage:

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].

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.

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.

Renal nerve stimulation identifies renal innervation and optimizes the strategy for renal denervation in canine

BACKGROUND

Renal denervation (RDN) was still performed without any intra-procedural method for nerve mapping. Whether renal nerve stimulation (RNS) is an efficient way to identify renal autonomic innervation and optimize the strategy for RDN remain to be worthy for further exploration.

METHODS

The characteristics of renal autonomic innervation at the sites with different blood pressure (BP) responses to RNS were explored. Then, dogs anatomically eligible for RDN were randomly assigned into elevated BP response ablation group, reduced BP response ablation group, and RNS-control group. The postoperative outcomes were measured at baseline and after 4 weeks follow-up.

RESULTS

The proportion of afferent sensory nerve was higher at elevated BP response sites (ERS) than reduced BP response sites (RRS) and non-response sites (NRS) (P = 0.012 and P = 0.004). Conversely, the proportion of parasympathetic nerve at RRS was the highest (RRS vs. ERS, P = 0.017; RRS vs. NRS, P = 0.023). More importantly, there was a significant correlation between systolic blood pressure changes and the area ratios of afferent sensory and parasympathetic nerve (R = 0.859; P < 0.001). In addition, ablation at BP-elevation sites can result in a significant decrease in BP and plasma norepinephrine (NE) after 4 weeks (P = 0.002; P = 0.008), while ablation at BP-reduction sites can lead to significant increases in BP and plasma NE (P = 0.016; P = 0.033).

CONCLUSIONS

RNS is an effective method to identify renal autonomic innervation. It could not only help to identify optimal target sites, but also avoid ablation of sympathetic-inhibitory areas during RDN.

Protective Felix-Culpa Effect of Superior Sympathetic Cervical Ganglion Degenerations on Prevention of Basilar Artery Spasm Following Subarachnoid Hemorrhage: A Preliminary Experimental Study

BACKGROUND

Posterior cerebral blood flow is regulated by the basilar arteries (BA). Its vasospasm of basilar arteries (BA) can occur following subarachnoid hemorrhage (SAH). Superior cervical sympathetic ganglia (SCG) fibers have a vasoconstrictor effect on the BA. We aimed to investigate the relationship between the degenerated neuron density of the SCG and the severity of BA vasospasm after experimental subarachnoid hemorrhage.

METHODS

Twenty-four rabbits were used. Five of them were used as the control group, and five of them were used as the SHAM group. Experimental subarachnoid hemorrhages were performed in the remaining fourteen animals (study group) by injecting homologous blood into cisterna magna. After three weeks of injection, neuron densities of SCG and the severity of BA vasospasm index values (VSI) were examined histopathologically and compared statistically.

RESULTS

The mean VSI was 0.669±0.1129 in the control group, 0.981±0.159 in the SHAM group, and 1.512±0.298 in the study group. The mean degenerated neuronal density of SCG was 436±79/mm³ in severe vasospasm (n=3), 841±101/mm³ in moderate vasospasm (n=4), and 1.921±849/mm³ in the less vasospasm detected animals (n=6).

CONCLUSION

This study shows an inverse relationship between the degenerated neuronal density in the SCG and VSI values. This finding indicates a diminished sympathetic input from the superior cervical ganglion (SCG) resulting in a beneficial (the Felix-culpa) effect by dilating the lumen diameter of the basilar artery (BA), so superior sympathetic cervical ganglion degeneration following SAH protects the basilar artery spasm.

First emerging evidence of the relationship between Onuf's nucleus degeneration and reduced sperm number following spinal subarachnoid haemorrhage: Experimental study

Lumbosacral pathologies can lead to infertility. Onuf's nucleus changes in these pathologies may have a role in low sperm number. This study aims to investigate the relationship between Onuf's nucleus degeneration and sperm number following spinal subarachnoid haemorrhage. 22 rabbits were used. They were divided into three groups; five of them were used as the control (GI), five as the SHAM (GII) and twelve as the study groups (GIII). The study group received 0.7 ccs autologous blood into the spinal subarachnoid space at the T12-L1 level. After two weeks, all animals were decapitated, and S1-S3 laminectomy was done. Neurodegenerative changes of Onuf's nucleus, pudendal ganglia (S3) following two weeks after spinal SAH, were examined; sperm numbers were calculated. Degenerated neuron density of the Onuf's nucleus (n/mm³ ), the pudendal ganglia (S3) (n/mm³ ) and mean sperm numbers were calculated as 5 ± 2, 8 ± 3/mm³ and 98.345 ± 12.776/mm³ in the control (GI), 20 ± 5/mm³ , 243 ± 66/mm³ and 91.841 ± 9.654/mm³ in the SHAM (GII), 143 ± 39/mm³ , 2,350 ± 320/mm³ and 68.549 ± 5.540/mm³ in the study group (GIII). In conclusion, there were statistically significant differences between groups. Onuf's nucleus may be responsible for decreased sperm number following spinal SAH.