Changes in the blood-nerve barrier after sciatic nerve cold injury: indications supporting early treatment

Risk factors for early neurological deterioration in acute isolated pontine infarction without any causative artery stenosis

BACKGROUND

This study aimed to investigate the risk predictors for early neurological deterioration (END) in isolated acute pontine infarction without any causative artery stenosis.

METHODS

In this retrospective study, patients with isolated acute pontine infarction within 72 h of symptom onset were enrolled between October 2017 and December 2021. END was defined as an increase in the National Institutes of Health Stroke Scale (NIHSS) score ≥ 2 points within the first week postadmission. Patients were divided into the END and the non-END groups. Multiple logistic regression analysis was used to evaluate independent predictors of END in patients with isolated acute pontine infarction.

RESULTS

A total of 153 patients were included in the final study (62 females; mean age, 67.27 ± 11.35 years), of whom 28.7% (47 of 153) experienced END. Multiple logistic regression analyses showed that infarct volume (adjusted odds ratio [aOR], 1.003; 95% CI, 1.001-1.005; P = 0.002) and basilar artery branch disease  (aOR, 3.388; 95% CI, 1.102-10.417; P = 0.033) were associated with END. The combined ROC analysis of the infarct volume and basilar artery branch disease for predicting END showed that the sensitivity and specificity were 80.9% and 72.6%, respectively.

CONCLUSION

Basilar artery branch disease and infarct volume were associated with END in acute isolated pontine infarction and may be useful prognostic factors for neurological progression.

Assessing residual motor function in patients with disorders of consciousness by brain network properties of task-state EEG

Recent achievements in evaluating the residual consciousness of patients with disorders of consciousness (DOCs) have demonstrated that spontaneous or evoked electroencephalography (EEG) could be used to improve consciousness state diagnostic classification. Recent studies showed that the EEG signal of the task-state could better characterize the conscious state and cognitive ability of the brain, but it has rarely been used in consciousness assessment. A cue-guide motor task experiment was designed, and task-state EEG were collected from 18 patients with unresponsive wakefulness syndrome (UWS), 29 patients in a minimally conscious state (MCS), and 19 healthy controls. To obtain the markers of residual motor function in patients with DOC, the event-related potential (ERP), scalp topography, and time-frequency maps were analyzed. Then the coherence (COH) and debiased weighted phase lag index (dwPLI) networks in the delta, theta, alpha, beta, and gamma bands were constructed, and the correlations of network properties and JFK Coma Recovery Scale-Revised (CRS-R) motor function scores were calculated. The results showed that there was an obvious readiness potential (RP) at the Cz position during the motor preparation process in the MCS group, but no RP was observed in the UWS group. Moreover, the node degree properties of the COH network in the theta and alpha bands and the global efficiency properties of the dwPLI network in the theta band were significantly greater in the MCS group compared to the UWS group. The above network properties and CRS-R motor function scores showed a strong linear correlation. These findings demonstrated that the brain network properties of task-state EEG could be markers of residual motor function of DOC patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11571-021-09741-7.

Construction and effect evaluation of different sciatic nerve injury models in rats

Background

The most commonly used experimental model for preclinical studies on peripheral nerve regeneration is the sciatic nerve injury model. However, no experimental study has been conducted to evaluate acute injury modes at the same time.

Objective

We conducted sciatic nerve transverse injury, clamp injury, keep epineurium and axon cutting injury, and chemical damage injury in rats to evaluate the degree of damage of the four different injury modes and the degree of self-repair after injury.

Methods

The sciatic nerve transverse injury model, clamp injury model, keep epineurium injury model, and chemical damage injury model were constructed. Then, the sciatic nerve function was assessed using clinical evaluation methods and electrophysiological examinations, as well as immunofluorescence and axonal counting assessments of the reconstructed nerve pathways.

Results

The evaluations showed that the transverse group had the lowest muscle action potential, sciatic functional index, nociceptive threshold, mechanical threshold, rate of wet gastrocnemius muscle weight, area of muscle fiber, and numbers of myelinated nerve fibers. The chemical group had the highest, while the clamp group and the keep epineurium group had medium.

Conclusion

Transverse injury models have the most stable effect among all damage models; chemical injury models self-recover quickly and damage incompletely with poor stability of effect; and clamp injury models and keep epineurium injury models have no significant differences in many ways with medium stability.

Potential Protective Effect of Vitamin C on Qunalphos-Induced Cardiac Toxicity: Histological and Tissue Biomarker Assay

Insecticides and toxicants abound in nature, posing a health risk to humans. Concurrent exposure to many environmental contaminants has been demonstrated to harm myocardial performance and reduce cardiac oxidative stress. The purpose of this research was to study the protective effect of vitamin C (Vit C) on quinalphos (QP)-induced cardiac tissue damage in rats. Eighteen albino male rats were randomly categorised into three groups (n = 6). Control, QP group: rats received distilled water. QP insecticide treatment: an oral administration of QP incorporated in drinking water. QP + Vit C group: rats received QP and Vit C. All the experiments were conducted for ten days. Decline of cardiac antioxidant biomarkers catalase (CAT) and reduced glutathione (GPx) along with increased proinflammatory markers tumour necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) indicated oxidative and inflammatory damage to the heart following administration of QP when compared to control rats. The light microscopic and ultrastructure appearance of QP-treated cardiomyocytes exhibited cardiac damage. Administration of Vit C showed decreased oxidative and inflammatory biomarkers, confirmed with histological and electron microscopic examination. In conclusion, Vit C protected the heart from QP-induced cardiac damage due to decreased inflammation and oxidative stress.

The association between high-sensitivity C-reactive protein at admission and progressive motor deficits in patients with penetrating artery infarctions

BACKGROUND

A fraction of patients with penetrating artery infarction (PAI) experience progressive motor deficit deterioration (PMD). We sought to investigate the role of high-sensitivity C-reactive protein (hs-CRP) at admission in predicting PMD.

METHODS

From January 2015 to September 2018, consecutive patients with PAI from three centers were prospectively enrolled in this study. PMD was defined as worsening of motor function score by ≥1 point on the National Institutes of Health Stroke Scale during the first 5 days after admission. Multivariable logistic regression analyses were performed to explore the relationship between hs-CRP and PMD in patients with PAI. We also performed receiver operating characteristic curve analysis and constructed a nomogram to assess the overall discriminative ability of hs-CRP in predicting PMD.

RESULTS

We ultimately included 544 patients (mean age, 65.4 ± 11.8 years). A total of 85 (15.6%) patients were identified to have PMD. Multivariate logistic regression analysis showed that hs-CRP was independently associated with PMD (P = 0.001). The optimal cutoff value for hs-CRP as a predictor for PMD was 3.48 mg/L, with a sensitivity of 73.64% and a specificity of 82.35% (area under curve, 0.792). Moreover, the nomogram we constructed indicated that higher level of hs-CRP was an indicator of PMD (c-index = 0.780, P < 0.001).

CONCLUSIONS

Our study suggested that hs-CRP might be a useful biomarker for predicting the risk of PMD in patients with PAI.

Pathophysiological Changes of Physical Barriers of Peripheral Nerves After Injury

Peripheral nerves are composed of complex layered anatomical structures, including epineurium, perineurium, and endoneurium. Perineurium and endoneurium contain many physical barriers, including the blood-nerve barrier at endoneurial vessels and the perineurial barrier. These physical barriers help to eliminate flux penetration and thus contribute to the establishment of a stable microenvironment. In the current review, we introduce the anatomical compartments and physical barriers of peripheral nerves and then describe the cellular and molecular basis of peripheral physical barriers. We also specifically explore peripheral nerve injury-induced changes of peripheral physical barriers, including elevated endoneurial fluid pressure, increased leakage of tracer, decreased barrier-type endothelial cell ratio, and altered distributions and expressions of cellular junctional proteins. The understanding of the pathophysiological changes of physical barriers following peripheral nerve injury may provide a clue for the treatment of peripheral nerve injury.

Identification of cold-responsive miRNAs in rats by deep sequencing

miRNA is an endogenously noncoding sRNA, which is involved in post-transcription gene expression regulation of growth, tumor development and stress survival. As a biological marker, miRNA has been used for the early diagnosis of diseases and the evaluation of some physiological state. We constructed two small RNA libraries with the serums of rats treated or not with cold conditions (4℃ for 12h) by deep sequencing, in order to understand the miRNAs' expressions of cold-exposed rats and find new cold-responsive biological markers. 485 conserved miRNAs and 287 novel miRNAs were identified in the two libraries by comparing to the known miRNAs of rat in miRBase 21.0 Differential expression analysis showed that 56 conserved miRNAs and 3 novel miRNAs were expressed differentially in low ambient temperature. The qRT-PCR results confirmed that rno-miR-151-3p, rno-miR-210-3p, rno-miR-425-5p, rno-miR-383-5p, rno-miR-92a-3p, rno-miR-98-5p and rno-miR-328a-3p decreased significantly in rats serums treated with cold exposure. The expressions of the 7 miRNAs changed significantly in cold-exposed rats' livers too. rno-miR-383-5p decreased significantly, but all the others increased significantly. Thus, the 7 miRNAs were considered as cold-responsive miRNAs of rat. 670 target genes of the 7 cold-responsive miRNAs were predicted. KEGG analysis showed that they were enriched in 28 pathways and most of them were enriched by metabolic pathway. Overall, the results of this study suggest an important role for selected miRNA's in the response to cold stress.

Dexamethasone prevents vascular damage in early-stage non-freezing cold injury of the sciatic nerve

Non-freezing cold injury is a prevalent cause of peripheral nerve damage, but its pathogenic mechanism is poorly understood, and treatment remains inadequate. Glucocorticoids have anti-inflammatory and lipid peroxidation-inhibiting properties. We therefore examined whether dexamethasone, a synthetic glucocorticoid compound, would alleviate early-stage non-freezing cold injury of the sciatic nerve. We established Wistar rat models of non-freezing cold injury by exposing the left sciatic nerve to cold (3–5°C) for 2 hours, then administered dexamethasone (3 mg/kg intraperitoneally) to half of the models. One day after injury, the concentration of Evans blue tracer in the injured sciatic nerve of rats that received dexamethasone was notably lower than that in the injured sciatic nerve of rats that did not receive dexamethasone; neither Evans blue dye nor capillary stenosis was observed in the endoneurium, but myelinated nerve fibers were markedly degenerated in the injured sciatic nerve of animals that received dexamethasone. After dexamethasone administration, however, endoneurial vasculopathy was markedly improved, although damage to the myelinated nerve fiber was not alleviated. These findings suggest that dexamethasone protects the blood-nerve barrier, but its benefit in non-freezing cold injury is limited to the vascular system.