Nerve conduction velocity and spinal reflexes may change in rats after fumonisin B1 exposure

Mycotoxin fumonisin B1 (FB1) a natural inhibitor of ceramide synthase contaminating mainly the corn-based food and feed may cause dysfunctions in the nervous system. In the present study peripheral neural dysfunctions were biomonitored after dietary FB1 exposure in rats. Daily oral doses of 6.2 mg/kg body weight/day FB1 were applied in rats for 2 weeks. Before and after FB1 treatment nerve conduction velocities of tibial and sciatic nerves and spinal reflexes were analyzed in vivo. Electrophysiological recordings of biphasic plantar EMG (M and H components) and evaluation of sensory and motor nerve conduction velocities were carried out. Nerve conduction velocities revealed decreasing tendencies after FB1 exposure. The flexor reflex and the H-components of the extensor reflex were significantly reduced. The proposed in vivo biomonitoring can reveal functional impairment of the peripheral nervous system caused by mycotoxin exposure. Reduction of conduction velocity and altered reflexes after FB1 exposure are suspected to be associated with modified signal transmission due to toxic systemic effects and possible changes in sphingolipid metabolism.     

An Electrophysiological Study of Acute Tetrodotoxin Poisoning

To evaluate the electrophysiological changes in patients with acute tetrodotoxin (TTX) poisoning from ingestion of globefish (Tetraodontidae) patients exposed to TTX were compared with age-matched controls. The cohort of TTX-poisoning cases was clinically subdivided into mild, moderate, or severe cases. The motor nerve conduction velocity (MCV), sensory nerve conduction velocity (SCV), F-wave, H-reflex, and somatosensory-evoked potentials (SEP) of the median, ulnar, and common peroneal nerve (CPN) were determined using established techniques. Four of the 64 (6.3%) TTX-poisoning cases died and were omitted from the final analysis. The MCV and SCV of the median, ulnar, and CPN nerves in all the TTX-poisoning cases were significantly slower than the healthy controls. Severe cases of TTX poisoning had more significant reduction in nerve function. Thus, electroneurophysiological analysis could be used to determine the extent, course, and range of nerve system damage in patients with acute TTX poisoning.     

显微手术治疗正中神经开放性损伤的临床效果分析

目的:分析显微手术治疗正中神经开放性损伤的临床效果。方法:选取2010年2月-2014年3月入住我院接受治疗的120例正中神经开放性损伤患者,随机分成观察组和对照组,每组60例。对照组行常规的手术治疗,观察组行显微手术进行治疗。术后随访6~48个月,比较两组患者正中神经的运动传导速度(MCV)、感觉传导速(SCV)以及正中神经功能优良率。结果:观察组正中神经功能优良率为93.33%,显著高于对照组70.00%(P0.05);两组患者治疗后正中神经MCV、SCV较治疗前均明显增加(P0.05);治疗后观察组MCV、SCV改善程度显著大于对照组(P0.01)。结论:显微手术治疗正中神经开放性损伤效果显著,为神经损伤修复奠定了理论基础,具有巨大的临床应用价值。     

低频脉冲刺激穴位疗法联合规律有氧运动对2型糖尿病周围神经病变患者感觉阈值、神经传导速度和血液流变学的影响

摘要 目的：探讨低频脉冲刺激穴位疗法联合规律有氧运动对2型糖尿病周围神经病变（DPN）患者感觉阈值、神经传导速度和血液流变学的影响。方法：选取2020年1月~2022年1月期间贵州中医药大学第二附属医院收治的DPN患者136例。根据随机数字表法分为对照组（n=68,常规治疗联合规律有氧运动）和研究组（n=68,对照组基础上接受低频脉冲刺激穴位疗法）,两组以14 d为1个疗程,均治疗2个疗程。对比两组疗效、感觉阈值、神经传导速度和血液流变学变化。结果：研究组的临床总有效率91.18%（62/68）高于对照组75%（51/68）（P<0.05）。两组治疗2个疗程后腓总神经感觉神经传导速度（SCV）、胫神经SCV、腓总神经运动神经传导速度（MCV）、胫神经MCV均升高,且研究组的变化程度大于对照组（P<0.05）。两组治疗2个疗程后全血黏度值(高切、低切)、红细胞压积、血浆黏度、血小板黏附率均下降,且研究组的变化程度大于对照组（P<0.05）。两组治疗2个疗程后神经症状积分、神经反射、感觉功能和总分均下降,且研究组的变化程度大于对照组（P<0.05）。结论：低频脉冲刺激穴位疗法联合规律有氧运动治疗DPN患者,可提高神经传导速度,改善感觉阈值和血液流变学。     

Effects of thermal acclimation on nervous conduction and muscle contraction in the frog Rana temporaria

The effects of season and acclimation temperature on the latency of the leg withdrawal reflex and three of its components have been studied: conduction velocity in the sciatic nerve, spinal conduction time, and contraction time of gastrocnemius muscle. The latency of the leg withdrawal reflex was markedly shortened by cold acclimation: the reaction times were at 6 degrees C 1.54 s in 4 degrees C acclimated and 3.97 s in 24 degrees C acclimated winter frogs. Also, the temperature dependence of the reflex latency was reduced by cold acclimation. Thus, frogs acclimated to cold responded to external stimuli in cold more rapidly than warm-acclimated ones. This cold adaptation of the reflex could not be explained by changes in its studied components. These made up only one-tenth of the reflex response time, and either did not show significant cold acclimation (muscle contraction and spinal conduction times in summer) or showed inverse acclimation, especially when measured at high temperatures (i.e. conduction velocities were reduced by acclimation to cold). Thus, the cold acclimation of the reflex response probably resides in the sensory component of the response. The inverse temperature adaptation response of conduction velocities may reflect a reduced ion permeability across cellular membranes in cold which decreases metabolic energy expenditure during inactive periods.     

经皮椎间孔镜TESSYS术与TLIF术治疗腰椎间盘突出症合并神经根管狭窄的疗效对比研究

摘要 目的：对比经皮椎间孔镜TESSYS术与经椎间孔入路腰椎椎体间融合术（TLIF）治疗腰椎间盘突出症（LDH）合并神经根管狭窄的疗效。方法：回顾性分析2016年4月~2019年4月期间徐州医科大学附属沭阳医院收治的96例LDH合并神经根管狭窄患者的临床资料,根据手术方式的不同将患者分为A组（n=48,采用TLIF术式治疗）和B组（n=48,采用经皮椎间孔镜TESSYS术治疗）,比较两组优良率、视觉疼痛模拟评分（VAS）、Oswestry 功能障碍指数（ODI）、椎间高度、滑脱程度、隐神经、腓肠神经等感觉神经传导速度（SCV）和胫神经、腓总神经等运动神经传导速度（MCV）,记录两组并发症发生情况。结果：B组优良率高于A组（P<0.05）。两组患者术后6个月VAS评分、ODI评分以及滑脱程度均降低,且B组低于A组（P<0.05）。两组患者术后6个月椎间高度、隐神经SCV、腓肠神经SCV、胫神经MCV、腓总神经MCV升高,且B组高于A组（P<0.05）。B组并发症发生率低于A组（P<0.05）。结论：与TLIF术式相比,经皮椎间孔镜TESSYS术治疗LDH合并神经根管狭窄的疗效显著,可有效减轻患者疼痛,提高腰背功能,明显改善双下肢神经功能,提高筋膜代偿能力,且并发症发生率更低,临床应用价值更高。     

Establishment of H reflex model in mice with minimal insult and measurement of nerve conduction velocity

The aim of the present study was to establish a minimally invasive H reflex model in mice for the benefit of the research of clinical spinal cord injury and related diseases. Minimally invasive surgery was performed in hind limb of Kunming mouse under light anesthesia. The skin was incised at the point of one-third of the distance from greater trochanter to the base of the cauda. A pair of fine copper conductors were inserted into the shallow muscle using a syringe needle. After the needles were withdrawed, the retained conductors were ligated and fixed with the tissues surrounding the sciatic nerve as the first pair of stimulating electrodes. Another pair of conductors were inserted and fixed in medial malleolus close to the tibial nerve as the second stimulating electrodes. Copper conductor was inserted passing the skin above the proximal end of the metatarsal and fixed as the recording electrode. The reference electrode was placed at the walking pad in the base of the big toe using the same method. Electromyography (EMG) was used to record M and H waves in planta pedis muscles. The stimulus was a square wave with a width of 0.2 ms and frequency of 0.3 Hz. The latency time of the M and H waves which were induced from the two pairs of stimulating electrodes was recorded. Nerve conduction velocity (NCV) was then calculated from the distance between the cathodes of the stimulating electrodes and the latency time difference of M or H waves. The result showed the achievement ratios of H reflex induction were 92.73% and 81.82% in sciatic and tibial nerves, respectively. The latency time of H wave was about 7~10 ms. Motor nerve conduction velocity (MNCV) obtained was (25.84 ± 4.70) m/s (n = 35), while sensory nerve conduction velocity (SNCV) was (31.45 ± 7.30) m/s (n = 35). The method established in the present paper is simple to practice, does slight harm to the animal, and can produce waveforms with little interference. With these advantages, the method can be applied for the study of the latency of H reflex, and it is suitable for the researches which demands good physical condition of experimental animal during H reflex study. This model can also be applied to the detection of SNCV and MNCV.     

A mouse model of inflammatory demyelinating neuropathy for the development of therapeutics: electrophysiological and morphological characterizations

To finalize a mouse model of inflammatory demyelinating neuropathy, we injected a solution containing a bovine pancreas protease, active at neutral pH, in the perineural space of the mouse left sciatic nerve (a nerve consisting of myelinated axons). The locomotive behaviour of animals was daily followed and, between 3 and 45 days after the injection, the sciatic nerves were removed from animals, studied using classical electrophysiological techniques and then, at least for some of them, examined using conventional microscopy. The right sciatic nerve, which did not receive a perineural injection, is a very good control, because it comes from the same animal as the left sciatic nerve which underwent the injection. The results obtained show that, under our experimental conditions, i) a demyelinisation of nerve fibres can be detected between 6 and 15 days after the injection of protease, resulting in a defective axonal conduction of action potentials, and ii) 45 days are sufficient to restore a normal axonal conduction. These results are interesting since they indicate that this mouse model can be used to test the ability of new pharmaceutical agents to counteract the defective nerve conduction of action potentials arising after an axonal demyelinisation, in the perspective of developing new useful molecules for the treatment of inflammatory demyelinating neuropathies.     

Remyelination in the chicken sciatic nerve

Remyelination in the chicken sciatic nerve occurring after the injection of diphtheria toxin was studied. The rates of fast axonal transport and conduction velocities were measured sixty days after the injection of the toxin. Fast axonal transport rates were found to have returned to normal in the remyelinated nerves, but conduction velocity was markedly reduced even though the birds appeared to walk normally. The remyelinated nerve fibres had on histological examination relatively thin myelin sheaths. Of greater interest was the number of Schmidt-Lanterman clefts observed in both the control and remyelinated nerves when viewed in the electron microscope.     

Motor and sensory conduction velocities and amplitude of nerve or muscle potentials in the normal rat according to age

The relative changes in sensory and motor nerve conductions and SNAP and CMAP amplitudes were studied on the sural and tibial posterior nerves in anesthetized male rats, between the 1st and the 23rd month. Neural growth was controlled with the measure of the nerve path length on the skin, between stimulating and recording cathodes for the sural nerve and proximal and distal stimulating cathodes for the tibial posterior nerve. The sural SCV and SNAP amplitude are consistent with a more accurate method than the H-reflex one. Similar changes were observed in both parameters. During the maturation of the peripheral nervous system, between the 1st and the 5th month, parameters rapidly increased. Over 14 months old, parameters decrease: the diminution of SNAP and CMAP amplitudes is characteristic of aging. The results were analyzed through quadratic and linear regression and were similar to those in young and elderly human patients. Parabola curves fitted the best way to represent the evolution of parameters. Moreover, the linear regression permitted to divide the rat life in 3 parts and to distinguish a period between the 6th and 13th months during which studied parameters are considered as constant. SCV, MCV, SNAP and CMAP amplitudes from the 1st to the 5th, from 6th to 13th and over the 14th month, could be used as reference.     

湿润烧伤膏联合封闭负压引流术对糖尿病足溃疡患者神经传导速度、溃疡创面血管新生及氧化应激水平的影响

摘要 目的：探讨湿润烧伤膏联合封闭负压引流术（VSD）对糖尿病足溃疡（DFU）患者神经传导速度、溃疡创面血管新生及氧化应激水平的影响。方法：选取我院2021年1月~2022年5月间收治的80例DFU患者,根据信封抽签法分为对照组（n=40）和研究组（n=40）。两组患者在住院期间均接受基础治疗,在此基础上,对照组接受VSD治疗,研究组在对照组的基础上接受湿润烧伤膏治疗。观察两组临床指标、生活质量、神经传导速度、溃疡创面血管新生及氧化应激水平的变化情况。结果：研究组的创面愈合率高于对照组,创面愈合时间短于对照组（P<0.05）。研究组治疗后踝肱指数（ABI）高于对照组（P<0.05）。研究组治疗后简明健康调查量表（SF-36）各维度评分高于对照组（P<0.05）。研究组治疗后腓总神经感觉神经传导速度（SCV）、腓总神经运动神经传导速度（MCV）、正中神经MCV、正中神经SCV高于对照组（P<0.05）。研究组治疗后内皮抑素（ES）低于对照组,血管内皮生长因子（VEGF）、碱性成纤维细胞生长因子（bFGF）高于对照组（P<0.05）。研究组治疗后丙二醛（MDA）、晚期蛋白氧化产物（AOPP）低于对照组,超氧化物歧化酶 （SOD）高于对照组（P<0.05）。结论：湿润烧伤膏联合VSD应用于DFU患者,可促进其创面愈合,提高神经传导速度和生活质量,可能与调节氧化应激水平、促进溃疡创面血管新生相关。     

The latency difference of the tibial and sural nerve sep: Peripheral versus central factors

The latency of the cortical SEP (CSEP) following stimulation of the posterior tibial nerve is nearly always shorter than the latency of the CSEP evoked by stimulation of the sural nerve. Till now this fact was believed to be due mainly to different conduction velocities within the peripheral nerves owing to the muscle afferents of the posterior tibial nerve. The surprising discovery that the lumbar and cervical SEPs exhibit much shorter time lags than the CSEPs led to the experiments described in this paper: during the registration of the peripheral sciatic nerve action potentials only slight differences in the conduction velocities were observed. Thereupon a topographical analysis was performed during which the minimum latency of the sural nerve CSEP was not measured at the usual C′_z electrode position but was found to be shifted to a more occipital and ipsilateral point.From these results it was concluded that, for the main part, the latency difference of the CSEPs results from ‘central factors’, which had already been postulated for the median nerve CSEP by Burke and coworkers.     

Hoffmann's reflex evoked on the soleus muscle and motor neural conduction velocity of the tibial nerve]

H reflex on the soleus muscle and motor tibial nerve conduction velocity are used to study peripheral nervous system maturation in 68 healthy children, from birth to 4 years of age. Proximal an distal conduction velocities develop in a parallel and approximately exponential way but proximal conduction velocities remain always faster. The latencies slightly decrease during the first 18 months of life and then increase very slowly.     

Motor and sensory nerve conduction velocities in Yucatan minipigs

Motor and/or sensory conduction velocities are used to assess peripheral nervous system disorders. Although the miniature pig represents a model of choice for long-term pharmacological experimentation, no study has so far been reported on this model in relation to the measurement of nerve conduction velocities. We developed the present technique and applied it to 34 3-18-month-old Yucatan minipigs. Motor and sensory conduction velocities were measured using the anterior tibial nerve and the internal plantar nerve, a branch of the posterior tibial nerve, respectively. The nerve conduction velocity data of motor (MNCV) and sensory (SNCV) nerves, together with the amplitude of the sensory nerve signal, were logarithmically dependent on the age of the tested animals (r(2)=0.92, 0.81 and 0.76, respectively). The mean values of MNCV and SNCV were 70.9 +/- 1.1 and 67.9 +/- 0.2 m/s, respectively, at the age of 16 months for these miniature pigs. In order to validate this model, we compared it with other known models when the velocities reached a plateau at the end of the study. These values were found to be higher than those in humans or rats, but are comparable to those of the baboon, one of the best large animal models for human pathologies. Because the physiology and metabolism of the minipig resemble those of humans, and due to its long lifetime, this animal represents a good model for studying the development of neuropathology.     

Vascularized versus nonvascularized nerve grafts: an experimental structural comparison

This study compared the success of nerve regeneration through conventional nonvascularized and vascularized nerve grafts in the sciatic nerve of rats. The number or size of regenerated axons between the two grafts was not significantly different. In addition, the ratio of axonal diameter to total diameter of the nerve, a measurement linearly related to conduction velocity, was not significantly different in the two groups. Thicker myelin sheaths were found around axons in the nonvascularized nerve grafts.     

Physiological studies on facial reflexes in the rat.

Experiments were performed on 36 male albino rats anaesthetized with pentobarbitone sodium and paralyzed with gallamine triethiodide. Recordings were made with single and multibarrel glass microelectrodes in the facial nucleus and monopolar silver wire electrodes on the lingual, facial, glossopharyngeal and hypoglossal nerves. The absolute refractory period for facial motoneurones is 2-3 ms, the relative refractory period has a duration of 26-34 ms and the range in axonal conduction velocities is from 15 to 45 m.sec-1. No evidence for afferent fibres in the muscle branches of the facial and hypoglassal nerves could be found. The lingual and glossopharyngeal nerves show reflex connexions with both the facial and hypoglassal nerves. The time courses of the potentiations and depressions of test facial antidromic field potentials following lingual and glossopharyngeal conditioning stimuli are given. Evoked synaptic activity and the distribution of field potentials in the facial mucleus following lingual and glossopharyngeal nerve stimulation are also described. The observed lingual and glossopharyngeal-facial reflexes are discussed with respect to blink reflexes.     

A novel animal model of partial optic nerve transection established using an optic nerve quantitative amputator

Background

Research into retinal ganglion cell (RGC) degeneration and neuroprotection after optic nerve injury has received considerable attention and the establishment of simple and effective animal models is of critical importance for future progress.

Methodology/Principal Findings

In the present study, the optic nerves of Wistar rats were semi-transected selectively with a novel optic nerve quantitative amputator. The variation in RGC density was observed with retro-labeled fluorogold at different time points after nerve injury. The densities of surviving RGCs in the experimental eyes at different time points were 1113.69±188.83 RGC/mm² (the survival rate was 63.81% compared with the contralateral eye of the same animal) 1 week post surgery; 748.22±134.75 /mm² (46.16% survival rate) 2 weeks post surgery; 505.03±118.67 /mm² (30.52% survival rate) 4 weeks post surgery; 436.86±76.36 /mm² (24.01% survival rate) 8 weeks post surgery; and 378.20±66.74 /mm² (20.30% survival rate) 12 weeks post surgery. Simultaneously, we also measured the axonal distribution of optic nerve fibers; the latency and amplitude of pattern visual evoke potentials (P-VEP); and the variation in pupil diameter response to pupillary light reflex. All of these observations and profiles were consistent with post injury variation characteristics of the optic nerve. These results indicate that we effectively simulated the pathological process of primary and secondary injury after optic nerve injury.

Conclusions/Significance

The present quantitative transection optic nerve injury model has increased reproducibility, effectiveness and uniformity. This model is an ideal animal model to provide a foundation for researching new treatments for nerve repair after optic nerve and/or central nerve injury.     

Localization and characteristics of parasympathetic preganglionic neurons in the sacral spinal cord

Antidromic responses of parasympathetic preganglionic neurons (PPN) in the sacral spinal cord evoked by stimulation of the pelvic nerve were studied in acute experiments on anaesthetized and immobilized cats by means of extracellular recording technique. The conduction velocities for preganglionic axons were calculated from the latency of these responses. It was shown that the upper limits of the conduction velocities for sacral parasympathetic axons extended the range (limit 12–15 m/sec) previously described: The velocities varied from 0.9 to 30.5 (mean 11.3±0.47) m/sec. According to the axonal conduction velocities the PPN were divided into four groups: the first group with conduction velocities from 0.9 to 3.0 m/sec; the second — 4.0–12; the third — 13–21; and the fourth group — 21–30 msec. PPN of the second group quantitatively prevailed — 57.6%, those of the third group represented 29.9%, and those of the first and fourth groups 6.8 and 6.2% of the total amount of PPN, respectively. Relative topic specialization of the second and third PPN groups was revealed. The density of PPN distribution in the intermediolateral region was higher in the second group than in the third one, while in ventral parts of the ventral horn concentration of the third PPN group was higher than that of other groups. The functional significance of PPN from the third group with fast-conducting axons (the conduction velocities correspond to those of group B fibers) is discussed.Translated from Neirofiziologiya, Vol. 25, No. 1, pp. 39–45, January–February, 1993.     

低频脉冲电刺激联合木丹颗粒对糖尿病周围神经病变的疗效

目的:探讨低频脉冲电治疗仪联合木丹颗粒对糖尿病周围神经病变的临床疗效。方法:收集我院收治的糖尿病周围神经病变患者90例,随机分为实验组和对照组。对照组患者给予甲钴胺片治疗,实验组患者给予木丹颗粒联合低频脉冲电刺激治疗。观察并比较两组患者治疗前后FBG、P2h BG及Hb Alc水平的变化情况,记录患者正中神经、腓神经的运动神经传导速度(MCV)及感觉神经传导速度(SCV),参照TCSS评分判定临床疗效。结果:治疗后,两组患者腓总神经及正中神经MCV、SCV均上升,与对照组比较,实验组上升显著,差异有统计学意义(P0.05);治疗后,两组患者TCSS评分均下降,与对照组比较,实验组下降更明显,差异有统计学意义(P0.05)。结论:低频脉冲电治疗仪联合木丹颗粒治疗糖尿病周围神经病变的疗效优于单用甲钴胺片治疗。     

Effects of nerve growth factor on nerve regeneration through a vein graft across a gap.

The limited availability of donor sites for nerve grafts and their inherent associated morbidity continue to stimulate research toward finding suitable alternatives. In the following study, the effect of direct administration of nerve growth factor (NGF) into a nerve conduit across a gap was tested in a rat sciatic nerve model. A 1-cm segment of the right sciatic nerve in Sprague-Dawley rats was resected, and the gap was then bridged using one of three methods: group I (NGF-treated group, n = 12), a vein graft filled with NGF (100 ng in 0.3-ml phosphate buffered saline); group II (control group, n = 12), a vein graft filled with phosphate buffered saline only; group III (standard nerve graft, n = 11), a resected segment of the sciatic nerve. All animals were evaluated at 3 and 5 weeks by behavioral testing and at 5 weeks by electrophysiologic testing. At 3 weeks, sensory testing showed that the latency to a noxious stimulus in group I animals (8.0 +/- 5.4 sec, mean +/- SD) was significantly lower than that of group II animals (13.2 +/- 6.5 sec), indicating that sensory recovery was superior in the animals receiving NGF. The mean latency of animals in group III was 12.9 +/- 6.5 sec, but the difference between the latencies of group I and group III did not reach statistical significance. At 5 weeks, there was no difference in sensory testing between groups. Motor function in groups I and III as measured by walk pattern analysis was superior to that of group II at 5 weeks (toe spread ratios 0.66 +/- 0.09, 0.48 +/- 0.07, and 0.69 +/- 0.09 for groups I, II, and III, respectively). Mean motor conduction velocities across the 1-cm gap were 8.6 +/- 4.7 m/sec, 2.5 +/- 0.7 m/sec, and 6.9 +/- 2.9 m/sec in groups I, II, and III respectively. The difference between groups I and III was not statistically significant, but the motor conduction velocity of group II was significantly slower than that of either group I or III (p < 0.002). The positive effects of NGF on regeneration of nerves across a gap seen in this study suggest that it may be useful for treating peripheral nerve injuries in combination with autogenous vein grafts.