Levocarnitine acetyl stimulates peripheral nerve regeneration and neuromuscular junction remodelling following sciatic nerve injury.

The effects of levocarnitine acetyl were investigated on both peripheral nerve regeneration and neuromuscular remodelling in male Sprague-Dawley rats, three months of age, following crush of their left sciatic nerve. Levocarnitine acetyl, 150 mg/kg/day in drinking water, was given from one week before to 5, 15, 20, and 60 days after nerve crush. The sciatic nerve was examined morphologically at all given times and morphometrically at 15, 20, and 60 days after the lesion. Morphology, at 5, 15, and 60 days, and morphometry, at 60 days after the nerve crush, were also performed on the neuromuscular junction in the soleus and extensor digitorum longus muscles. Five days after nerve crush, complete axonal degeneration was observed in both control and treated rats. At 15 and 20 days, recovery from injury in treated animals was better than in controls, as shown by a significantly higher increase in the number of regenerating axons. At the same times, denervated endplates were present in both groups. At 60 days, axonal regeneration restored the number of axons to normal values in all injured animals, while their size maturation was greater in treated rats than in controls. A markedly lower number of degenerating elements was found in treated animals. In the neuromuscular junctions of the soleus and extensor digitorum longus muscles, nerve terminal branch points were reduced in the lesioned rats in comparison with uninjured ones. However, morphometric analysis revealed a greater endplate complexity in treated animals in which, at 60 days after nerve crush, nerve terminal branching and sprouting index values were significantly higher than in controls. It is concluded that levocarnitine acetyl exerts a beneficial effect on nerve regeneration processes and synaptic remodelling in crush-induced neuropathies.     

Enhancement of nerve fibre regeneration by nucleotides after peripheral nerve crush damage. Electrophysiologic and morphometric investigations.

The effect of nucleotide administration on the regeneration of myelinated nerve fibres following crush injury to the sciatic nerve of the rat was studied using both morphometric and electroneurophysiologic techniques. After a standardized localized crush lesion of the right sciatic nerve, rats were given nucleotides daily at a dosage of 3.0 mg/kg body wt uridine monophosphate (UMP), 2.5 mg/kg body wt cytidine monophosphate (CMP) or 3.0 plus 2.5 mg/kg body wt UMP plus CMP, respectively. Observations were made after 20, 40 and 60 days of nerve regeneration for comparison with age-matched crushed or nonoperated controls. Electroneurophysiologic studies of right sural nerves were performed as single fibre measurements. Morphometry was performed on semithin transverse sections of the right common peroneal nerve with a fully automatic interactive image analysis system. Forty days after crush injury the single fibre conduction velocity of all type II afferents in the UMP/CMP treated group was significantly accelerated. There was a trend (10% greater than or equal to p greater than or equal to 5%) to increase of mean efferent single nerve fibre function at this time. Morphometry of nerve fibres revealed a trend to enlargement of mean fibre area and mean fibre diameter related to increased myelin area and myelin thickness. After 60 days, there was a trend to increase of single fibre conduction velocity of all type II afferents in the UMP/CMP treated group. Automated morphometry revealed a significant increase for the following parameters: fibre area, fibre diameter, myelin area, myelin thickness and axon area.(ABSTRACT TRUNCATED AT 250 WORDS)     

Regeneration of the sciatic nerve in mice and rats exposed to trichloroethylene

The effects of trichloroethylene (TCE) on regeneration of the sciatic nerve after a crush lesion was tested in mice and rats. A lesion was made on nerves in unexposed animals and in animals pre-exposed to TCE for 20 days. Experimental animals were then exposed to TCE for an additional 4 days. Exposures were continuous at 150 or 300 ppm. Regeneration was measured by pinching the outgrowing nerve fibers. Regeneration was retarded in the TCE-exposed animals compared to the air-exposed controls. Mice were more sensitive to TCE exposure than rats. Liver weight increased in TCE-exposed mice but there was no correlation between this effect and that on nerve regeneration.     

依达拉奉对大鼠坐骨神经损伤后脊髓脂质过氧化的影响

目的:探讨自由基清除剂依达拉奉对坐骨神经损伤后神经功能及脊髓脂质过氧化反应的影响.方法:Wistar大鼠48只,随机分为3组:坐骨神经挤压伤组、依达拉奉治疗组、假手术组.分别于7、14、21、28 d检测各组大鼠坐骨神经功能指数(SFI)、脊髓内过氧化物歧化酶(SOD)和丙二醛(MDA)的变化.结果:伤后各组大鼠SFI均降低,挤压伤组大鼠SFI较依达拉奉治疗组低(P<0.05),神经功能恢复较治疗组缓慢.伤后挤压伤组大鼠脊髓内SOD活性升高,依达拉奉治疗组大鼠脊髓内SOD活性与假手术组相比升高不明显(P>0.05).伤后挤压伤组大鼠脊髓内MDA含量上升明显,依达拉奉治疗组大鼠脊髓内MDA含量在各个时间点均显著低于挤压伤组大鼠脊髓内MDA含量(P相似文献   

The effect of alpha-liponic acid, vitamin B or gangliosides on the regeneration of traumatically damaged peripheral nerves in the rat. A comparative, morphometric study

The sciatic nerve of male rats was crushed in accordance with a standardized method. To investigate the positive influence of different substances on nerve regeneration, the rats received daily injections of alpha-liponic acid, vitamin B or gangliosides. After 11 days the sciatic nerves were removed and the area distal to the crush site was analyzed histomorphometrically. Compared with the control group, there was only a slight increase in the number of regenerating fibres and their diameters following treatment with alpha-liponic acid or vitamin B. However, in the ganglioside-treated rats the differences, indicative of accelerated regeneration, were statistically significant.     

蛇毒神经生长因子对大鼠坐骨神经损伤的修复作用

目的 研究外源性给予蝰蛇蛇毒提取的神经生长因子(sNGF)对大鼠坐骨神经损伤的修复作用。方法 建立大鼠坐骨神经钳夹模型。sNGF直接作用于损伤的坐骨神经，通过趾间距和Tarlov评分的评定，观察坐骨神经修复的情况。结果 sNGF治疗组的趾间距及Tarlov评分的恢复明显好于空白对照组。结论 局部给予蛇毒神经生长因子能明显改善损伤的坐骨神经功能。     

丁咯地尔对大鼠坐骨神经损害的保护作用

目的观察丁咯地尔对坐骨神经损害后恢复的影响。方法SD大鼠100只随机分为正常组、模型组、甲钴胺组(阳性对照组,104μg·kg~(-1))、丁咯地尔组(40 mg·kg~(-1))。以大鼠坐骨神经挤压伤建立动物模型,以坐骨神经传导速度、坐骨神经干病理切片(光镜、电镜)为观察指标,考察丁咯地尔对坐骨神经损害后恢复的影响。结果wk 4时甲钴胺组和丁咯地尔组均能显著增加坐骨神经传导速度,甲钴胺组与模型组比较有显著差异(P<0.05),丁咯地尔组与模型组比较有非常显著差异(P<0.01);4 wk时丁咯地尔组和甲钴胺组髓鞘形态结构接近正常,而模型组神经髓鞘溃变程度很高。结论丁咯地尔对坐骨神经损害有确切的修复作用。     

Enhancement of regeneration by Org 2766 after nerve crush depends on the type of neural injury.

The neurotrophic effects of the adrenocorticotropin (ACTH)-(4-9) analog Org 2766 (Met(O2)-Glu-His-Phe-D-Lys-Phe) were studied in rats recovering from a sciatic nerve crush. Org 2766 (10 micrograms/rat s.c., every 48 h) increased the number of myelinated axons reinnervating a previously denervated sciatic nerve by 32% (P less than 0.01), as assessed 13 days after crush lesioning, and facilitated recovery of sensorimotor functioning by 14% (P = 0.05), as measured by foot withdrawal after stimulation of the footsole with hot air. However, these facilitating effects were only seen if the nerve was lesioned using forceps with grooved jaws and not if forceps were used with cross-hatched jaws. Endoneural tubes and Schwann cells of the sciatic nerve appeared to be better preserved after crushing with grooved rather than cross-hatched jaws. Our data indicate that the regeneration-enhancing effects of Org 2766 are dependent on the type of injury applied to the endoneurium and endoneural tubes of the sciatic nerve and suggest that endoneural tissue may mediate the neurotrophic properties of Org 2766.     

吡咯喹啉醌对大鼠损伤坐骨神经的修复作用

目的探讨吡咯喹啉醌 (PQQ)对损伤的坐骨神经的修复作用。方法Wistar大鼠 30只 ,制备坐骨神经夹损模型 ,术后每日分别局部注射一定量的PQQ、神经生长因子 (NGF)和生埋盐水 14d ,检测大鼠趾间距和电生理指标 ,比较PQQ对损伤神经的修复作用。结果PQQ及NGF组的趾间距及电生理指标在前两周的恢复明显好于生理盐水组 ,且有显著性差异。结论PQQ能明显改善损伤的坐骨神经功能     

Studies on the degenerative and regenerative phenomena occurring after transection and repair of the sciatic nerve in rats: effects of acetyl-L-carnitine

The effects of acetyl-L-carnitine on some degenerative and regenerative phenomena following sciatic nerve transection in rats, were studied. In Experiment 1, acetyl-L-carnitine was administered intraperitoneally at the dose of 50 mg/kg/day for 28 and 56 days following transection and microsurgical repair of the sciatic nerve. On day 56, the acetyl-L-carnitine-treated rats showed a significantly (p less than 0.05) better motor recovery ("clinical assessment") of the peroneal component of the sciatic nerve than the control rats. Twenty-eight days after nerve repair, the acetyl-L-carnitine-treated rats showed a significantly higher (p less than 0.05) number of myelinated axons in the postlesional nerve stump than control rats. Finally, the treated rats had a significantly lower (p less than 0.05) presence of atrophic fibres in the extensor digitorum longus muscle. In Experiment 2 the sciatic nerve was cut. To prevent spontaneous regeneration, a metallic clip was applied to the distal nerve stump and then the nerve stumps were positioned in different anatomical compartments. After surgery, a group of rats was treated with acetyl-L-carnitine dissolved in the drinking water (75 mg/kg/day). Another group of rats received normal water and served as the control group. Three, 6, 9, 12 and 18 months postoperatively, in the rats of both groups, the proximal sciatic nerve stump was injected with horseradish peroxidase to label the spinal cord neurons of the sciatic nerve nucleus. While in untreated rats the number of horseradish peroxidase-labelled neurons decreased with the increase in denervation time, in acetyl-L-carnitine-treated rats the number of horseradish peroxidase-labelled neurons remained stable for as long as 12 months of denervation and decreased only after 18 months of denervation. Furthermore, acetyl-L-carnitine-treated rats showed a significantly higher (p less than 0.05) number of horseradish peroxidase-labelled neurons with respect to untreated rats both after 9 and 12 months of denervation. In Experiment 3, the sciatic nerve was cut and then repaired after periods of 3, 6, 9, 12, and 18 months. Four months after nerve repair, the sciatic nerve was again cut and the proximal nerve stump was injected with horseradish peroxidase to label the spinal cord neurons of the sciatic nerve nucleus. Both acetyl-L-carnitine-treated and untreated rats showed a tendency to have an increased number of horseradish peroxidase-labelled neurons with respect to intact rats of correspondent ages.(ABSTRACT TRUNCATED AT 400 WORDS)     

Levocarnitine acetyl promotes the regeneration of peripheral sensory axons and reduces the hypertrophy of axotomized spinal cord motoneurons in rats.

In previous studies, the neurotrophic action of levocarnitine acetyl on the regeneration of the sciatic nerve in rats has been demonstrated. The present study investigated the particular effect of levocarnitine acetyl on the initial stages of sciatic nerve regeneration. In the first 8 days after sciatic nerve lesion caused by crushing (Group A) or cutting (Group B), the rats of both groups were divided into 2 subgroups: treated rats received daily intraperitoneal levocarnitine acetyl (a megadose of 100 mg in saline solution); untreated rats only received saline solution. Treatment started on the day of operation. The regeneration growth rate of sensory fibres was studied using the pinch test. The size of the axotomized spinal motoneurons was studied using retrograde axonal tracers (horseradish peroxidase or Fast blue). The results showed that: (a) levocarnitine acetyl promoted the elongation of sensory fibres in the first 8 days following the crushing or sectioning of the sciatic nerve, but the data were only statistically significant (p less than 0.01) for the first 3 days after crushing; (b) levocarnitine acetyl accelerated the velocity of sensory fibre regeneration when compared to untreated rats by 16% in the first 3 days after nerve crushing, by 14% in the first 4 days after nerve section, and by 32% from the 5th to the 8th day after nerve section; (c) levocarnitine acetyl promoted a significant reduction in spinal motoneuron hypertrophy when compared to untreated rats at both 4 and 8 days after sciatic nerve section.(ABSTRACT TRUNCATED AT 250 WORDS)     

睫状神经营养因子对周围神经损伤后功能恢复的影响

目的：研究睫状神经营养因子（ＣＮＴＦ）对受损周围神经功能恢复的影响。方法：将８０只大鼠左侧坐骨神经切断后行神经外膜吻合,随机分为两组。实验组腹腔内注入基因重组人ＣＮＴＦ,对照组注入等量生理盐水（ＮＳ）。术后行坐骨神经功能指数（ＳＦＩ）测定、电生理检测、轴突图像分析及霍乱毒素－辣根过氧化物酶（ＣＢ－ＨＲＰ）逆行追踪。结果：ＣＮＴＦ组ＳＦＩ恢复率、各项电生理及轴突图像分析指标、ＣＢ－ＨＲＰ标记的脊髓前     

Impaired induction of nerve ornithine decarboxylase activity in the streptozotocin-diabetic rat is prevented by the aldose reductase inhibitor ponalrestat.

1. The present study was designed to investigate if the aldose reductase inhibitor ponalrestat is capable of preventing the impairment of the response of ornithine decarboxylase (ODC) to nerve crush in streptozotocin (STZ)-diabetic rats. 2. ODC activity was measured in the dorsal root ganglia of crushed and uncrushed contralateral sciatic nerve of non-diabetic, ponalrestat-treated non-diabetic, STZ-diabetic and ponalrestat-treated STZ-diabetic rats. 3. Twenty four hours after crush, a significant (P less than 0.001) increase in the ratio of ODC activity in ganglia of crushed relative to uncrushed nerves was found in non-diabetic but not in diabetic rats, as expected. In the ponalrestat-treated diabetic rats the ratio was significantly higher (P less than 0.001) than that in the untreated diabetic rats and was not different from that in the non-diabetic group. 4. Ponalrestat also significantly decreased absolute levels of ODC activity in ganglia of uncrushed nerves from diabetic and non-diabetic animals. Despite the near-normal induction of ODC activity by nerve crush in the ponalrestat-treated diabetic animals, absolute ODC activity remained lower than that in ganglia of uncrushed nerves from non-diabetics. 5. We conclude that ponalrestat is able to prevent the impaired induction of ODC in experimental diabetes. The results, however, call into question the relationship between impaired ODC induction and diabetes-induced defects in nerve regeneration, which are insensitive to ponalrestat.     

Dissociation between biochemical and functional effects of the aldose reductase inhibitor, ponalrestat, on peripheral nerve in diabetic rats.

1. The aim of the study was to examine the effects in rats of two different doses of the aldose reductase inhibitor, ponalrestat, on functional measures of nerve conduction and sciatic nerve biochemistry. 2. After 1 month, streptozotocin-induced diabetes produced 22%, 23% and 15% deficits in conduction velocity of sciatic nerves supplying gastrocnemius and tibialis anterior muscles and saphenous sensory nerve respectively compared to controls. These deficits were maintained over 2 months diabetes. 3. Slower-conducting motor fibres supplying the interosseus muscles of the foot did not show a diabetic deficit compared to onset controls, however, there was a 13% reduction in conduction velocity after 2 months diabetes relative to age-matched controls, indicating a maturation deficit. 4. Resistance to hypoxic conduction failure was investigated for sciatic nerve trunks in vitro. There was an increase in the duration of hypoxia necessary for an 80% reduction in compound action potential amplitude with diabetes. This was progressive; after 1 month, hypoxia time was increased by 22% and after 2 months by 57%. 5. The effect of 1-month treatment with the aldose reductase inhibitor, ponalrestat, on the abnormalities caused by an initial month of untreated diabetes was examined. Two doses of ponalrestat were employed, 8 mg kg-1 day-1 (which is equivalent to, or greater than, the blockade employed in clinical trials), and 100 mg kg-1 day-1. 6. Sciatic nerve sorbitol content was increased 7 fold by diabetes. Both doses were effective in reducing this; 70% for 8 mg kg-1 day-1, and to within the control range for 100 mg kg-1 day-1.(ABSTRACT TRUNCATED AT 250 WORDS)     

中华眼镜蛇毒神经生长因子对神经元的保护作用

探讨中华眼镜蛇毒神经在子对受损神经元的保护作用。方法 钳夹损伤成年大鼠坐骨神经,造成脊髓背根神经节感觉神经元和脊髓前角运动神经元变性的动物模型,用酶组织化学图像分析观察神经生长因子对受损神经脊髓节段的抗氟化的酸性磷酸酶和乙酰胆碱酯酶活性的影响。结果 神经生长因子能明显提高受损神经脊髓节段的抗氟化物酸性磷酸酶和乙酰胆碱酯酶活性。结论 神经生长因子对神经元有保护作用。     

Acrylamide administration alters protein phosphorylation and phospholipid metabolism in rat sciatic nerve

The effects of ACR on protein phosphorylation and phospholipid metabolism were assessed in rat sciatic nerve. After 5 days of ACR administration (50 mg/kg/day) an increase in the incorporation of 32P into phosphatidylinositol-4,5-bisphosphate, phosphatidylinositol-4-phosphate, and phosphatidylcholine was detected in proximal sciatic nerve segments. In contrast, no changes in phospholipid metabolism were observed in distal segments. After 9 days of ACR treatment when neurotoxicological symptoms were clearly apparent, a generalized increase in radiolabel uptake into phospholipids was noted exclusively in proximal nerve regions. ACR-induced increases in phospholipid metabolism were toxicologically specific since comparable administration of MBA (108 mg/kg/day X 5 or 9 days) produced only minor changes. ACR intoxication was also associated with a rise in sciatic nerve protein phosphorylation. After 9 days of ACR treatment, phosphorylation of beta-tubulin, P0, and several unidentified proteins (38 and 180 kDa) was increased in distal segments. In contrast, chronic administration of MBA caused increases in phosphorylation of beta-tubulin and the major myelin proteins of proximal nerve segments. In cell free homogenates prepared from sciatic nerves of treated and control rats, MBA caused an increase in phosphorylation of major myelin proteins similar to its effect in intact proximal nerve segments. The most striking effect observed in nerve homogenates of ACR-treated rats was a marked decrease in phosphorylation of an 80-kDa protein. Addition of ACR (1 mM) to homogenates of normal nerve had no effect on protein phosphorylation. Our results indicate that changes in the phosphorylation of phospholipids and proteins in sciatic nerve might be a component of the neurotoxic mechanism of ACR.     

小鼠2.5s神经生长因子对大鼠和小鼠受损坐骨神经再生的影响

目的：证实ＮＧＦ促进坐骨神经再生的作用，方法：夹断小鼠和大鼠坐骨神经轴索，测再生同索计数及分类，在比目鱼肌远（Ｄｉｓ），近（Ｐｒｏ）端测神经，肌肉电潜伏期（ＮＭＥＰＬ），结果：小鼠ＮＧＦｉｍ０．５－１ｋＢＵ．ｋｇ＾－１２０ｄ增加轴索再生率，２－４ｋＢＵ．ｋｇ＾－１减轻比目鱼肌萎缩，大鼠ＮＧＦｉｍ１（４０ｄ），２（３０和４０ｄ），４（２０，３０，４０ｄ）ｋＢＵ．ｋｇ＾－１均显著增加损伤神经的轴索再生     

神经节苷脂对大鼠坐骨神经损伤后神经纤维变化的作用研究

连续8d每天给大鼠ip10，20和50mg／kg神经节苷脂，d9将大鼠坐骨神经损伤，损伤后d7用图象分析仪检查该神经内有髓神经纤维变性情况。其中50mg／kg组有髓神经纤维华勒氏变性程度与对照组（ip生理盐水）相比大幅度减小；10mg／kg组无效；20mg／kg组有轻度减轻作用。以上各组中的有髓神经纤维轴突直径和神经纤维直径以及G值与正常有髓神经纤维相似，P＞0．05。正常大鼠坐骨神经损伤后d15观察发现其内的再生有髓神经纤维数约为正常坐骨神经的三分之一，其中的轴突直径和神经纤维直径均较大，约为正常有髓神经纤维的二倍，G值则较小，P＜0．05。结果提示，大鼠神经损伤前预防性给予的神经节苷脂能储存于机体内，在神经损伤后，它们迅速释放并参与神经的营养与生长修复工作，主要起到防止神经纤维华勒氏变性的作用，而不是促进变性的神经纤维再生。同时也说明，神经损伤之前机体内储存足量神经节苷脂对于预防神经华勒氏变性是重要的。     

Age-related changes in substance P-immunoreactive nerve structures of the rat recto-anal region

The recto-anal region is innervated by extrinsic and intrinsic nerves and a number of neuropeptides including substance P (SP) have been suggested to participate in the regulation of intestinal movements. We examined the age-related changes in the distribution of SP-immunoreactive nerve structures in the distal part of the rat large intestine. Using immunohistochemistry, the presence of SP was studied in fresh tissues from Wistar rats at different ages taken at three sampling sites, the distal rectum, anal canal and internal anal sphincter. In the 15-day old rats the myenteric plexus of the distal rectum and anal canal was well outlined by numerous SP-immunoreactive varicose nerve fibres encircling immunonegative perikarya. In the circular muscle layer, nerve fibres and small nerve bundles ran parallel to the muscle cells, while in the longitudinal muscle layer, only occasional nerve fibres were seen. At the level of the internal anal sphincter, no myenteric ganglia were present. Here, thin varicose fibers ran parallel to the smooth muscle cells. In the 3-month old rats, a larger number of intensely staining SP-immunoreactive nerve fibres were found and in the circular muscle layer, thicker nerve strands were observed. In the 26-month old rats, the density and staining intensity of SP-immunopositive nerve fibres in the myenteric plexus was lower than in the 3-month-old rats. Similar changes in the SP-immunostained fibres in the internal anal sphincter were observed. Degenerative alterations in SP-containing fibres during aging appear to play a role in ano-rectal motility and sphincter control.     

Vasoactive agent buflomedil up-regulated expression of vascular endothelial growth factor in a rat model of sciatic nerve crush injury

Objectives:

To study the effect of Buflomedil on the morphological repair on crush injury of sciatic nerve and also the expression of vascular endothelial growth factor (VEGF).

Materials and Methods:

Rat sciatic nerves were crushed by pincers. All of the 400 Sprague Dawley rats were randomly divided into: Sham-operated; saline; saline + VEGF-antibody; Buflomedil; and Buflomedil + VEGF antibody groups. The expression of VEGF in dorsal root ganglia (DRGs), following crush injury to sciatic nerves, was studied by RT-PCR, immunohistochemistry. The effects of Buflomedil on expression of VEGF and repair of neural pathology were also evaluated.

Results:

VEGF mRNA was significantly increased in Buflomedil and Buflomedil + VEGF-antibody groups, compared with other groups. The number of VEGF-positive neurons was significantly increased in the Buflomedil and the saline groups. Besides, Buflomedil also caused less pathological changes in DRGs.

Conclusions:

The vasoactive agent Buflomedil may decrease the pathological lesion and improve the functional rehabilitation of peripheral nerves, which may correlate to upregulation of the expression of VEGF, following crush injury to the peripheral nerves.KEY WORDS: Crush injury, dorsal root ganglion, sciatic nerve, vascular endothelium growth factor, vasoactive agent