FK506在异体神经移植过程中对雪旺细胞和巨噬细胞的影响

目的从形态学角度研究FK506在异体神经移植后神经修复过程中对雪旺细胞增殖和巨噬细胞凋亡的影响。方法体外培养纯化雪旺细胞,流式细胞仪检测FK506促雪旺细胞增殖和促巨噬细胞凋亡作用,ELISA法检测FK506促雪旺细胞分泌神经生长因子(NGF)及促巨噬细胞分泌白细胞介素-1(IL-1)的含量,荧光显微镜和透射电镜对巨噬细胞的凋亡进行形态学观察与鉴定。结果流式细胞仪和ELISA检测结果显示FK506可促进雪旺细胞增殖并分泌NGF,促进巨噬细胞凋亡并分泌IL-1,荧光显微镜和透射电镜下观察到巨噬细胞凋亡前期和凋亡小体的出现。结论在形态学角度FK506可以在早期促进雪旺细胞增殖和分泌NGF,并促进巨噬细胞凋亡和IL-1的分泌,进而促进外周神经再生。     

Functional recovery after facial and sciatic nerve crush injury in the rat

OBJECTIVES: To systematically record rat facial nerve recovery following crush injury to the main trunk with respect to ocular and vibrissial function and to compare the rates of facial and sciatic nerve recovery from crush injury in the same animals. This serves as a means of validating the functional parameters of facial nerve recovery against the well-known measure of hind limb function, the Sciatic Function Index. METHODS: The main trunk of the facial nerve and the proximal segment of the sciatic nerve were exposed in all animals. Both nerves were subjected to standardized crush injury and subsequent daily functional testing. After a plateau of functional recovery was achieved, the animals were killed, and the distances between the sites of injury and the end musculature were measured, which allowed determination and comparison of recovery rates in both systems. RESULTS: All crush injuries resulted in loss of electrical conductivity, as proven by intraoperative proximal nerve stimulation. Recovery of ocular and vibrissial motor function occurred starting at postoperative day (POD) 9 and continuing through POD 20. Hind limb function returned later (POD 14-34); however, when corrected for distance, the sciatic recovery rate (2.26 mm/d) appeared to match that of the facial nerve (1.5-2.4 mm/d). CONCLUSIONS: Recovery after facial nerve crush injury follows a predictable time course, and the rate of recovery is consistent with that of sciatic nerve injury. Return of the blink reflex, loss of vibrissial fibrillations, and return of vibrissial sweeping function appear to be internally consistent functional measures of facial recovery. These quantitative measures will be useful for future facial nerve manipulation studies.     

FK506对大鼠坐骨神经再生作用的实验研究

押目的对FK506促神经再生的作用及药物应用方法进行初步探讨。方法雄性SD大鼠60只,随机分成三组,切断双侧坐骨神经制成坐骨神经再生室模型。A组(对照组)再生室内注入生理盐水;B组(全身用药组)再生室内注入盐水,颈后皮下注射FK5061mg/kg,连续14天;C组(局部用药组)再生室内注入1μg/mlFK506。于术后一定时间内观察神经损伤局部的免疫反应熏检测腓肠肌湿重、组织形态学及图像分析、电生理学。结果B、C组神经损伤局部淋巴细胞浸润程度较A组轻微。6周时B组各测定结果明显优于A组;C组各指标好于A组,但不具有统计学意义。结论穴1雪全身应用FK506(1mg/kg)具有神经保护和神经营养作用,可加快神经功能的恢复。(2)局部应用FK506(1μg/ml)对早期损伤神经有一定的保护作用,但对神经再生的促进作用不确切。     

Effect of FK506 on functional recovery after facial nerve injury in the rat

OBJECTIVE: To examine the effect of the immunosuppressive agent FK506 on the rate of functional recovery of the rat facial nerve after crush injury. METHODS: Forty rats underwent facial nerve crush injury and were randomly assigned to 4 experimental groups: isotonic sodium chloride solution control, FK binding protein 52 (FKBP-52) antibody control, FK506, and FK506 and FKBP-52 antibody. Rats underwent daily recovery testing from postoperative day 9 until postoperative day 21 by videotaping 3 validated variables in this model: blink reflex return, vibrissial fibrillation loss, and return of vibrissial sweeping symmetry. RESULTS: FK506-treated animals demonstrated improved recovery in all 3 variables compared with control animals. The FK506 and FKBP-52 antibody group demonstrated improved recovery of only the return of the blink reflex. CONCLUSIONS: FK506 accelerated functional recovery of facial nerve function after crush injury. Neuroregeneration was inhibited by FKBP-52 antibody in the rat midface but not the upper face. FK506 may be a viable adjuvant treatment for facial nerve neurapraxic injury.     

Effects of intrathecal morphine, clonidine and baclofen on allodynia after partial sciatic nerve injury in the rat

BACKGROUND: Increased response to mechanical or cold stimulation of hind paws was observed in rats with partial sciatic nerve injury as a result of photochemically induced ischemia. The present study examined the effects of intrathecal morphine, clonidine and baclofen on the allodynia-like responses. METHODS: The left sciatic nerves of rats were irradiated for 2 min with an argon ion laser under chloral hydrate anesthesia. The threshold of paw withdrawal to mechanical stimulation was determined with a series of monofilaments (von Frey hairs). The response to cold stimulation was tested by spraying ethyl chloride on the plantar surface of the paw. When rats were exhibiting stable mechanical and cold allodynia-like behaviors after nerve injury, the effects of i.t. morphine (1, 2, 7 microg), clonidine (1, 2, 7 microg) and baclofen (0.1, 0.2, 0.7, 9 microg) in a cumulative dose regime were investigated. RESULTS: Intrathecal morphine dose-dependently alleviated the mechanical and cold allodynia without inducing motor impairment or sedation. Intrathecal clonidine did not alter the response of hind paws to mechanical stimulation, but reduced the cold allodynia. Intrathecal baclofen reduced the responses of rats to mechanical stimulation only at doses that also induced profound motor deficits. CONCLUSIONS: The present data suggest that intrathecal morphine, and to some extent clonidine, but not baclofen, alleviated the abnormal pain-related behaviors in this new rat model of partial peripheral nerve injury. Differences in the pharmacological profile between the present model and other models of peripheral nerve injury are discussed.     

FK 506加速周围神经损伤修复后的功能恢复

目的：探讨FK506对大鼠坐骨神经横断伤修复后肢体功能恢复的影响。方法：45只SD大鼠高位切断坐骨神经后原位缝合，术后实验组（25只）用FK506灌胃，对照组（20只）不给药，于术后第1、2、3、5个月检测术肢比目鱼肌肌湿重恢复率，小腿三头肌肌力恢复率，坐骨神经功能指数及皮层体感诱发电位（SEEP）的潜伏期，结果：实验组肢体功能恢复时间较对照组提前大约2个月。结论：FK506可加速周围神经横断伤修复后肢体功能的恢复。     

FK506应用于冷藏保存同种异体神经移植的作用

目的　研究FK5 0 6结合冷藏保存应用于同种异体神经移植后对神经再生的实验效果。方法　 60只雌性Wistar大鼠做为受体动物模型 ,按移植物的不同分为 4组 ,每组 15只大鼠。A组 :新鲜同种异体神经移植组 ;B组 :冷藏保存同种异体神经移植组 ;C组 :冷藏保存同种异体神经移植组 ,同时服用FK5 0 6,剂量为 ( 2mg/kg) 1·d-1;D组 :冷藏保存同种异体神经移植组 ,同时服用FK5 0 6,剂量为 ( 0 .5mg/kg) -1·d-1。于术后 4、8、10周各组分别行大体观察 ,测定比目鱼肌肌湿重 ,运动神经传导速度 (MNCV)和运动动作电位 (CMAP)的波幅及组织学变化。结果　术后 8、10周时 ,4组中以C组神经再生最好 ,D组神经再生好于A、B组 ,但与C组相比则较差。轴突计数、肌湿重的统计学分析 ,有明显差别。结论　冷藏保存预处理同种异体神经移植后可以加速神经再生及功能恢复。     

Detrimental effects of immobilization on functional recovery after sciatic nerve crush

Peripheral-nerve trauma has been a challenge to surgeons, with significant advances in the surgery of repair. Immobilization of the injured limb after repair has been the traditional method of treatment. Although peripheral-nerve regeneration has been studied extensively, the correlation between functional recovery and the immobilization period has not been well-documented. In the present study, the authors studied the effects of immobilization on axonal regeneration after sciatic crush injury. They found a detrimental effect of immobilization on the functional recovery.     

Neural cell transplantation effects on sciatic nerve regeneration after a standardized crush injury in the rat

The goal of the present study was to assess whether in vitro-differentiated N1E-115 cells supported by a collagen membrane would enhance rat sciatic nerve regeneration after a crush injury. To set up an appropriate experimental model for investigating the effects of neural cell transplantation, we have recently described the sequence of functional and morphologic changes occurring after a standardized sciatic nerve crush injury with a nonserrated clamp. Functional recovery was evaluated using the sciatic functional index, the static sciatic index, the extensor postural thrust, the withdrawal reflex latency, and ankle kinematics. In addition, histomorphometric analysis was carried out on regenerated nerve fibers by means of the 2D-disector method. Based on the results of the EPT and of some of the ankle locomotor kinematic parameters analyzed, the hypothesis that N1E-115 cells may enhance nerve regeneration is partially supported although histomorphometry disclosed no significant difference in nerve fiber regeneration between the different experimental groups. Therefore, results suggest that enrichment of equine type III collagen membrane with the N1E-115 cellular system in the rat sciatic nerve crush model may support recovery, at least in terms of motor function. The discrepancy between functional and morphological results also suggests that the combined use of functional and morphological analysis should be recommended for an overall assessment of recovery in nerve regeneration studies.     

Functional effects of local thyroid hormone administration after sciatic nerve injury in rats

This study investigates potential functional effects of thyroid hormone (T3) on peripheral nerve regeneration in rats. Forty adult male Lewis rats were included in this study. After complete transection of the right sciatic nerve, the gap between the stumps was bridged with a silicone tube. In the first experimental group (group A, n = 12), T3 solution was used to fill the tube, whereas a sterile buffer solution was used in nontreated rats, (group B, n = 12). Additionally, sham operation with surgical incision and mobilization of the sciatic nerve without any other intervention was performed (group C, n = 10). In a few animals, alpha-segment of the nerve was excised and the stumps were reversed to exclude the possibility of regeneration (group D, n = 6). The process of peripheral nerve regeneration was assessed by functional indices at 3, 6, 9, 13, and 17 weeks postoperatively. Mid-stance angle, at the ankle, measured in degrees, was used as a kinematic index and the withdrawal reflex (measured in grams of applied force) was used to evaluate the return of sensory function. Kinematic indexes were not different between the groups A and B at all time points of the evaluation. Sensory function was significantly different in T3-treated animals compared with buffer-treated control group (x vs. y, P = 0.031) at 9 weeks. Thereafter, sensory function was comparable between groups. In conclusion, T3 seems to accelerate the return of sensory function after complete transection of the sciatic nerves in Lewis rats without a significant effect on motor nerve recovery.     

Effects of tobacco smoke on recovery after nerve crush injury in rats

The effects of tobacco smoke on nerve healing after crush injury was studied in a rat model. Thirty-six animals were randomized equally into smoke-exposed or nonsmoke-exposed groups. Two nerve crush injuries were performed on the right posterior tibial nerve of each animal at 4-week intervals to mimic a sustained or chronic nerve injury. Recovery of the two groups was assessed with walking track analysis and nerve histomorphometry. There was no difference in the rate of nerve recovery based on walking track analysis in the smoke-exposed animals compared with nonexposed animals. The study also failed to demonstrate any significant difference between the two groups as assessed by histomorphometric criteria.     

FK506 binding protein 12 is expressed in rat penile innervation and upregulated after cavernous nerve injury

To evaluate whether FK506 and other immunophilin ligands may have potential therapeutic efficacy for erectile function preservation after penile nerve injury, we demonstrated localizations of the immunophilin FK506 binding protein 12 (FKBP 12) in intact and injured rat penile nerves and correlated these findings with localizations of neuronal nitric oxide synthase (nNOS), which neuronally forms nitric oxide for mediation of penile erection, in response to systemically administered FK506. Adult male Sprague-Dawley rats were subjected to unilateral right cavernous nerve forceps crush injury and administered FK506 (1 mg/kg i.p.) or saline at the same time and daily up to 7 days. At 1, 3 and 7 days after injury, bilateral cavernous nerves and major pelvic ganglia were collected for nNOS immunohistochemistry, FKBP 12 immunohistochemistry, and FKBP 12 in situ hybridisation. Protein expressions of nNOS and FKBP 12 were observed in major pelvic ganglion, cavernous nerve and nerve terminals within the rat penis as well as mRNA expression of FKBP 12 observed in the rat major pelvic ganglion neuronal cell bodies to a minimal extent at baseline conditions. After cavernous nerve injury, nNOS immunoreactivity was observed to be slightly diminished in ipsilateral penile nerve structures at only one day following injury while both FKBP 12 protein and mRNA expressions were observed to be increased at each interval of study. FK506 treatment did not affect staining of intact or injured nerves. Our demonstration that FKBP 12 is localized to penile innervation in the rat and becomes upregulated following cavernous nerve crush injury, independent of FK506 treatment, suggests that this immunophilin mediates a neurotrophic mechanism. Whether FK506 affords neuroprotection that preserves penile erection through FKBP 12 upregulation is unclear.     

Effects of delaying FK506 administration on neuroregeneration in a rodent model

FK506 is an immunosuppressant drug that has been shown experimentally to stimulate nerve growth and speed functional recovery, when administered immediately after peripheral nerve injury. However, the clinical scenario of a peripheral nerve injury is often associated with either a delayed diagnosis or reconstruction. The purpose of this study was to determine the efficacy of FK506 on neuroregeneration with delayed administration. Thirty-two Lewis rats underwent tibial nerve transection with immediate repair. Animals were left untreated, or were treated with daily injections of FK506 (2 mg/kg), started on the day of surgery, postoperative day 3, or postoperative day 5. Animals underwent walking track analysis to assess functional nerve recovery. Nerves were harvested for histomorphometric analysis on postoperative days 21, 28, and 42. Histomorphometry demonstrated that all treatment groups, regardless of the time of drug initiation, demonstrated evidence of enhanced neuroregeneration, compared to the untreated group. Histomorphometric data from groups harvested on day 21 demonstrated a statistically significant improvement in neuroregeneration in the immediate and 3-day delay groups. Therefore, the beneficial effects of FK506 on neuroregeneration are not restricted to immediate administration, but these effects significantly diminish when FK506 is administered 3 days after nerve injury.     

Dehydroepiandrosterone as an enhancer of functional recovery following crush injury to rat sciatic nerve

This study was designed to investigate the effect of dehydroepiandrosterone (DHEA) on the recovery of the rat sciatic nerve following crush injury. A standard hemostat system was used to create the injury, with a length of 1.5 mm in three groups of 18 animals each. In group I, the crush injury was applied without any treatment. In groups II and III, vehicle (ethylene glycol) and DHEA solutions were injected subepineurally 30 min following the crush injury. Sciatic function index (SFI), toe contracture measurement, gastrocinemius muscle weight, total number of myelinated fibers, fiber diameters, myelin thickness, and axon/fiber cross-sectional ratio were measured at 3, 6, and 12 weeks. The SFI values in the DHEA group showed a faster return to normal values confirmed at 3 and 6 weeks (P < 0.05). The number of myelinated fibers and fiber diameters at 6 and 12 weeks were significantly higher in the DHEA group (P < 0.05). In this study, the subepineural injection of DHEA following crush injury was found to enhance functional recovery of the rat sciatic nerve.     

Magnesium administration provokes motor unit survival,after sciatic nerve injury in neonatal rats

Background  

We examined the time course of the functional alterations in two types of muscles following sciatic nerve crush in neonatal rats and the neuroprotective effect of Mg²⁺.