Influence of laser (660 nm) on functional recovery of the sciatic nerve in rats following crushing lesion

With the aim of accelerating the regenerative processes, the objective was to study the influence of gallium–aluminum–arsenide (GaAlAs) laser (660 nm) on functional and histomorphological recovery of the sciatic nerve in rats. The sciatic nerves of 12 Wistar rats were crushed divided into two groups: control and laser therapy. For the latter, GaAlAs laser was utilized (660 nm, 4 J/cm², 26.3 mW and 0.63 cm² beam), at three equidistant points on the lesion, for 20 days. Comparison of the sciatic functional index (SFI) showed that there was a significant difference only between the pre-lesion value of the laser therapy group and that after the 21st day in the control group. It was concluded that the parameters and methods utilized demonstrated positive results regarding the SFI over the time period evaluated.     

Effect of low-power pulsed laser on peripheral nerve regeneration in rats

The purpose of this study was to determine whether low-power pulsed laser irradiation could affect the regeneration of a 10-mm gap of rat sciatic nerve created between the proximal and distal nerve stumps, which were sutured into silicone rubber tubes. After 8 weeks of recovery, pulsed laser-irradiated groups at frequencies of 5 kHz and 20 kHz both had significantly lower success percentages of regeneration (50% and 44%, respectively) compared to sham-irradiated controls (100%). In addition, qualitative and quantitative histology of the regenerated nerves revealed a less mature ultrastructural organization with a smaller cross-sectional area and a lower number of myelinated axons in both pulsed laser-irradiated groups than in controls. These results suggest that pulsed laser irradiation could elicit suppressing effects on regenerating nerves.     

Aging delays the regeneration process following sciatic nerve injury in rats

The present study investigated the effect of aging on muscle reinnervation in rats following a crush nerve injury. Using confocal laser scanning microscopy, we examined the spatial correlation of terminal Schwann cells (TSCs) or axon terminals with acetylcholine receptor (AChR) sites at neuromuscular junctions (NMJs). Compared to young rats (4 months of age), aged rats (24 months of age) demonstrated damaged TSC extensions and delayed regeneration. Post-injury endplate abnormalities in aged rats correlated with the degree of TSC degeneration. In the late stages of reinnervation, pathologic changes were seen in old rats, including multiple innervations, terminal sprouting, and poorly formed collateral innervation in NMJs. Our results suggest that the impaired TSC-axon interaction in aged rats delays the reinnervation process.     

Double-blind randomized study evaluating regeneration of the rat transected sciatic nerve after suturing and postoperative low-power laser treatment

This double-blind randomized study evaluated the therapeutic effect of low-power laser irradiation (LPLI) on peripheral nerve regeneration, after complete transection and direct anastomosis of the rat sciatic nerve. After this procedure, 13 of 24 rats received postoperative LPLI, with a wavelength of 780 nm laser, applied transcutaneously, 30 min daily for 21 consecutive days, to corresponding segments of the spinal cord and to the injured sciatic nerve. Positive somatosensory evoked responses were found in 69.2 percent of the irradiated rats (p = 0.019), compared to 18.2 percent of the non-irradiated rats. Immunohistochemical staining in the laser-treated group showed an increased total number of axons (p = 0.026), and better quality of the regeneration process, due to an increased number of large-diameter axons (p = 0.021), compared to the non-irradiated control group. The study suggests that postoperative LPLI enhances the regenerative processes of peripheral nerves after complete transection and anastomosis.     

Effects of nerve growth factor on crushed sciatic nerve regeneration in rats

The effects of nerve growth factor (NGF) on crushed sciatic nerve regeneration were studied in 30 rats, with 60 bilateral nerves. The nerves were crushed at a site 6 mm distal to the sciatic notch by the standard technique and 3 mm wide crush injuries were created. Then 2.1 μl of normal saline in the control groups and an equal volume of NGF solution (containing 1 μg of NGF) in the NGF-treated groups was injected into the crush sites and followed for 12, 28, and 56 days, respectively. At the end of the observation, electrophysiological evaluation was carried out; then samples 10 mm distal to the crush site were removed and prepared for histological and morphometric studies. Evoked muscle action potential (MAP) was recorded in 50% of the NGF-treated group at 12 days but not in the control group; the difference was statistically significant (P<0.05). The motor nerve conduction velocity (MNCV) was increased in NGF-treated groups compared with control groups at 28 and 56 days (P<0.05). Morphometrically, significantly more regenerated myelinated fibers (RMFs) were seen at 12 days, and larger diameter RMFs were found at 12, 28, and 56 days in NGF-treated groups than in control groups. These results indicate that topically applied NGF stimulates nerve regeneration and promotes function recovery in crushed rat sciatic nerves. © 1995 Wiley-Liss, Inc.     

Low-level laser therapy improves repair following complete resection of the sciatic nerve in rats

The aim of this study is to analyze the effects of low-level laser therapy (LLLT) on the regeneration of the sciatic nerve in rats following a complete nerve resection. Male Wistar rats were divided into a control injury group, injury groups irradiated with a 660-nm laser at 10 or 50 J/cm², and injury groups irradiated with an 808-nm laser at 10 or 50 J/cm². Treatment began 24 h following nerve resection and continued for 15 days. Using the sciatic functional index (SFI), we show that the injured animals treated with 660 nm at 10 and 50 J/cm² had better SFI values compared with the control injury and the 808-nm groups. Animals irradiated with the 808-nm laser at 50 J/cm² show higher values for fiber density than do control animals. In addition, axon and fiber diameters were larger in animals irradiated with 660 nm at 50 J/cm² compared to the control group. These findings indicate that 660-nm LLLT is able to provide functional gait recovery and leads to increases in fiber diameter following sciatic nerve resection.     

Pyrroloquinoline quinone enhances regeneration of transected sciatic nerve in rats

Slowregenerationofinjuredperipheralnerve,asamajorreason,contributesalottothepooroutcomeofneuralfunctionalrecovery.Satisfactorynerverehabilitationnotonlydependson applyingaperfectskillofmicrosurgery,butalsoneeds afitenvironmentfornerveregeneration.Drugsfor…     

电针对大鼠坐骨神经再生影响的功能评价

目的从功能恢复评价电针对神经再生的促进作用。方法建立大鼠坐骨神经损伤模型，将９０只ＳＤ大鼠随机分为损伤对照组和电针组两组。分别于术后２、４、６、１０周测定运动神经传导速度、小腿三头肌肌力及坐骨神经功能指数，并以自身健侧作对照得出其恢复率。同时测定术后１周感觉神经再生的距离。结果电针组术后１周感觉神经再生距离及２、４、６、１０周运动神经传导速度、肌力、ＳＦＩ等的恢复率均明显优于对照组。结论电针可以促进损伤神经的再生，明显提高神经功能的恢复     

促红细胞生成素促进大鼠坐骨神经再生作用的实验研究

目的 探讨促红细胞生成素(Erythoropoietin,EPO)对大鼠坐骨神经损伤修复后神经再生的影响,为周围神经损伤的临床治疗提供实验依据.方法 雄性SD大鼠40只,随机分为两组,即EPO组和神经生长因子(NGF)组,用硅胶管桥接10 mm的坐骨神经缺损,EPO组和NGF组分别注射EPO和NGF.术后4周和8周时每组分别提取10只大鼠,以坐骨神经功能指数(SFI)、运动神经传导速度(MNCV)、形态学观察和蛋白基因产物9.5(PGP 9.5)免疫组织化学染色,评估EPO对大鼠坐骨神经再生的影响.结果 术后4周SFI,EPO组为[(-78.85±3.87),x-±s,下同],NGF组为(-79.98±4.58),差异无统计学意义(P>0.05);术后8周SFI,EPO组为(-60.26±2.91),NGF组为(-64.65±4.11),差异有统计学意义(P<0.05).术后4周和8周时,EPO组MNCV、有髓神经纤维数目以及PGP9.5免疫阳性神经纤维的平均光密度和积分光密度均优于NGF组,差异有统计学意义(P<0.05).结论 EPO 能促进大鼠坐骨神经损伤后的修复与再生.     

Use of a low-power nerve stimulator during sciatic nerve block

The use of a low-power nerve stimulator to aid nerve location during the performance of sciatic nerve block was compared with a conventional anatomically based technique. The success rate, both in terms of the production of an effective block and the duration of postoperative analgesia, was significantly higher in the stimulator groups than in the non-stimulator groups. The implications of the study for both clinical and teaching practice are discussed.     

Osteoporosis following chronic constriction injury of sciatic nerve in rats

Osteopathic changes sometimes occur in patients with complex regional pain syndrome (reflex sympathetic dystrophy and causalgia). We aimed to investigate whether such osteopathic changes occurred in rats with chronic constriction injury (CCI) of the sciatic nerve. A CCI of the sciatic nerve was established in a unilateral hind limb in 39 adult Sprague-Dawley rats, which were killed 1, 2, 3, 5, or 7 weeks after the CCI procedure. Bone mineral content (BMC) and bone mineral density (BMD) in extracted tibial bones were measured using a dual-energy X-ray absorptiometer, and the number of osteoclasts in the metaphyseal regions was counted by the use of tartrate-resistant acid phosphate (TRAP) staining. BMC was significantly decreased, compared with that of the contralateral side, 1 to 7 weeks after CCI, and BMD was decreased 2 to 7 weeks after the procedure in the ipsilateral tibial bones, compared with BMD in the contralateral bones. The number of TRAP-positive multinucleated osteoclasts in the ipsilateral bones was significantly increased at 2, 3, and 5 weeks after the CCI, when compared with the number of these osteoclasts in the contralateral bones. The results of the present study demonstrate that osteopathic changes are associated with chronic constrictive injury of the sciatic nerve. Received: July 4, 2001 / Accepted: September 13, 2001     

Stimulation of regeneration of the sciatic nerve by experimentally induced inflammation in rats.

The effects of application of a chromic catgut suture (conditioning lesion) placed close to the sciatic or tibial nerves on regeneration of the sciatic nerve after a crush lesion (test lesion), that had been induced after an appropriate conditioning interval (two or four weeks) were assessed. The catgut suture induced an inflammatory reaction around the nerve during the four weeks after application of the catgut suture (conditioning interval) but no signs of degeneration of nerve fibres were seen. There was a significant increase in length of outgrowth of sensory nerve fibres as measured by the pinch reflex test when the test lesion was applied after two and four weeks' exposure to the catgut suture. The rate of regeneration was increased by about 11% when the catgut suture had been applied for four weeks before the test lesion was made. The findings indicate that an inflammatory reaction around a peripheral nerve may act as a conditioning lesion, thereby stimulating regeneration of the nerve.     

Ultrastructural study of rabbit sciatic nerve regeneration following experimental excisional transection and autograft reconstruction

Summary This experimental study presents the ultrastructure of regenerating sciatic nerve of the rabbit, after transection and immediate end to end anastomosis, using perineural fascicular nerve autograft, in a sterile environment.Twenty-four hours, 1, 2, and 6 weeks after the anastomosis, the treated sciatic nerves were exposed and three segments were excised and studied. The first at the region of the graft and the others from the proximal and distal stump of the nerve, in the vicinity of the graft suture. The sections taken from the proximal part showed that the nerve structure was identical with the control. Degeneration and regeneration of nerve fibres were observed on the sections taken from the region of the grafts and from the distal parts. Macrophagic activity appeared mainly one week after the operation. Fibroblastic invasion started 24 hours after operation. A moderate amount of collagen fibres was gradually formed. The fibres were disposed in parallel with the neuraxon. Schwann cells were slightly affected initially but consequently they fully recovered and showed signs of extra-activity of the cytoplasm organelles,e.g., enlargement of the granular endoplasmic reticulum cisternae.The present study showed that the bridging of experimental gaps of rabbit's sciatic nerve, by means of autograft and by use of perineural suturing, was sucessful. The regenerating nerve fibres were growing through the graft towards the distal part of the nerve. In this process Schwann cells and fibroblastic activity play a key role, which is most favourably influenced by using the technique described in this paper.     

损伤大鼠坐骨神经诱导运动神经元凋亡的初步报告

目的探索成年大鼠坐骨神经高位损伤后是否出现运动神经元细胞的凋亡。方法取鼠龄为５～６周的成年雄性ＳＤ大鼠２４只,体重１２０～１５０ｇ。大鼠分组：（１）正常对照组,６只大鼠;（２）实验组：１８只大鼠。高位切断并结扎其坐骨神经,按手术先后随机分成术后５、１４、２１天３个不同时间组。按术后不同时间处死动物。用４％多聚甲醛经心脏灌注后,切取Ｌ４～６节段腰髓,制成石蜡切片。采用原位末端脱氧核糖核苷酸转移酶介导的ｄＵＤＰ标记法标记凋亡的神经元。结果对照组未出现阳性标记的细胞。神经损伤后第５天有１只大鼠伤侧前角出现３个阳性标记的凋亡运动神经元。伤后第１４天、２１天出现凋亡神经元的数目分别为２．２±１．２及５．２±２．３个（ｘ±ｓｘ,下同）。结论当成年大鼠坐骨神经切断并被结扎后,由于阻断了神经营养因子的逆行运输,可以导致运动神经元的凋亡。     

应用Laminin促进周围神经再生的研究

目的探讨局部应用Laminin（LN）对周围神经再生的影响。方法将34只SD大鼠分为4组,1～3组每组10只,手术切除双侧10mm坐骨神经并用硅胶管套接,左侧套管内注入LN0．6μg,右侧注入生理盐水作对照。术后1、3、4个月分别进行电生理和组织学检查。另4只鼠于术后3个月行辣根过氧化物酶逆行示踪检查。结果LN治疗组术后1、3、4个月时的神经肌肉动作电位、运动神经传导速度、再生有髓神经纤维数量及髓鞘厚度均明显优于对照组。相应节段脊髓前角和背根神经节标记神经元明显多于对照组。结论LN可促进周围神经损伤后的再生。     

补气通络方对大鼠坐骨神经轴突再生的影响

目的观察由黄芪、人参、当归、川芎、丹参等中药组成的补气通络方对促进大鼠损伤坐骨神经再生的效应,为临床用药提供依据.方法用48只雄性清洁级Wistar大鼠,行右坐骨神经切断后即刻神经外膜缝合法造模,后将大鼠随机分成4组补气通络胶囊组、补气通络注射液组、维生素B1+B6组和空白对照组,每组12只.于造模术成功及处置后4周、8周和12周,从每组随机抽取4只大鼠取坐骨神经进行轴突计数,以神经轴突再生恢复率作为观测指标进行验证.结果补气通络胶囊组和补气通络注射液组大鼠坐骨神经轴突再生恢复率均优于维生素B1+B6组及空白对照组(P<0.05或P<0.01).结论补气通络方有助于周围神经损伤后神经轴突的再生.