颞骨内面神经缺损几丁质室修复的实验研究

目的探讨几丁质室修复颞骨内面神经缺损的可行性。方法采用生物材料几丁质室桥接兔骨内面神经缺损24只(侧),硅胶室作为对照组24只(侧),术后1、3和5个月对再生神经分别进行大体观察、电生理测试、组织学检查以及数字形态学分析。结果①术后3个月,近端神经纤维已通过几丁质室进入远端神经,术后5个月,新生神经更显成熟;②神经诱发电位显示再生神经传导功能恢复良好,实验组和对照组之间差异无显著性;③再生神经均以有髓神经纤维为主,轴突发育良好,超微结构显示髓鞘板层明暗相间、结构清晰,轴浆细胞器丰富;④术后5个月,几丁质组再生神经纤维面积恢复率、轴突面积恢复率及轴突数目恢复率均达71％以上,与硅胶组比较差异均无显著性。结论几丁质室修复颞骨内面神经缺损可取得良好的再生效果。     

神经生长因子在面神经损伤修复中作用的实验研究

目的研究神经生长因子（ｎｅｒｖｅｇｒｏｗｔｈｆａｃｔｏｒ，ＮＧＦ）在面神经损伤修复中的作用。方法将新西兰家兔３０只双侧面神经上颊支横断后置入硅胶神经再生腔，一侧注入ＮＧＦ为实验侧，另侧注入生理盐水为对照侧。术后４周和８周各取１５只家兔进行组织学观察及形态定量分析。结果术后４周，实验侧再生神经成功１１支，神经髓鞘厚度０．７７９±０．４７５μｍ，有髓轴突计数共２０２４±１９９９；对照侧再生神经成功８支，髓鞘厚度０．４１３±０．１３２μｍ，有髓轴突计数共３６８±１７１，ｔ检验两侧差异有显著性（Ｐ＜０．０５）。术后８周，再生神经更显成熟，再生神经有髓轴突直径、面积、髓鞘厚度及轴突计数均明显优于对照侧，两侧差异有显著性（Ｐ＜０．０５）。结论ＮＧＦ在面神经损伤修复中具有促进作用。     

颞骨内面神经缺损几丁质室修复的实验研究

目的 探讨几丁质室修复颞骨内面神经缺损的可行性。方法 采用生物材料几丁质室桥接兔骨内面神经缺损24只（侧）,硅胶室作为对照组24只（ 侧）,术后1、3和5个月对再生神经分别进行大体观察、电生理测试、组织学检查以及数字形态分析。结果 ①术后3个月,近端神经纤维已通过几丁质室进入远端神经,术后5个月,新生神经更显成熟;②神经诱发电位显示再生神经传导功能恢复良好,实验组和对照之间差异无显著性;③再生神经均有以髓神经纤维为主,轴突发育良好,超微结构显示髓鞘板层明暗相同、结构清晰,轴浆细胞器丰富;④术后5个月,几丁质组再生神经纤维面积恢复率、轴突面经及轴突数目恢复率均达71％以上,与硅胶组比较差异均无显著性。结论 几丁质室修复颞骨内面积神经损可取得良好的再生效果。     

一氧化氮合酶抑制剂对面神经损伤后再生神经纤维的作用

目的：探讨一氧化氮合酶抑制剂在面神经损伤后对再生神经纤维的作用。方法：选用豚鼠４０只。制造面神经离断动物模型;腹腔注射和再生室给一氧化氮合酶竞争性抑制Ｌ－Ｎ＾ω－硝基精氨酸甲酯（Ｌ－ＮＡＭＥ）和生理盐水。光境下对经Ｓｅｖｉｅｒ－Ｍｕｎｇｅｒ改良法轴突染色和ＳｏｌｏｃｈｒｏｍｅＣｙａｎｉｎｅ髓鞘染色的再生神经纤维的近端及远端的轴突根数、有髓轴突根数,髓鞘量级数进行定量观察。结果：术后８周再生室抑制剂     

睫状神经营养因子对面神经损伤的修复作用

目的探讨局部应用睫状神经营养因子对面神经损伤的修复作用。方法将成年新西兰兔面神经上颊支切除5mm,在断端间置入硅胶再生室,实验组室内注入睫状神经营养因子,对照组用生理盐水。术后4周和8周进行电生理学、组织病理学观察和形态学定量分析。结果术后4周,两组电刺激面神经很少能引发面肌兴奋,有髓轴索计数,轴索直径和面积t检验,两组差异有显著性意义(P<0.05)。术后8周面神经复合肌动作电位,实验组运动神经传导速度明显短于对照组,有髓轴索计数,轴索直径和面积实验组大于对照组(P<0.05)。结论局部应用睫状神经营养因子可促进面神经损伤的修复。     

切断家兔外周面神经的轴突再生:轴突再生数目与行为和诱发面阻活动的关系

外周面神经压碎性损伤已成功地在人体和豚鼠实验中得到恢复。临床上,面神经横断性损伤立即作直接的端一端吻合术可获得最好的运动功能,尤其在神经远端分支。但是,面神经损伤患者中只有小部分可行直接吻合术．绝大多数面神经损伤需其他修复方式。该研究以切断家兔面神经颊支,用三种不同方式分析面神经的再生,神经修复５周后观察肌肉的自发行为、电生理学表现及有髓鞘运动轴突数目并研究它们之间的关系。三种修复方式为端一端直接吻合,自体神经移植及硅酮神经套管术。定量分析：９根家兔面神经各切除５ｍｍ节段,计算每段有髓鞘轴突总数…     

骨髓间质细胞植入变性骨骼肌修复面神经缺损实验研究

目的利用骨髓间质细胞植入微波变性骨骼肌桥接大鼠面神经缺损,研究骨髓间质细胞在面神经修复中的作用。方法骨髓间质细胞培养;大鼠面神经10mm缺损模型制备、手术修复及细胞移植;对大鼠移植段再生神经电生理测试并进行轴突计数。结果术后二周,细胞植入组轴突再生明显;术后八周,细胞移植组再生轴突计数、神经传导速度及动作电位振幅均高于单纯变性骨骼肌组。结论骨髓间质细胞植入可以促进面神经损伤的修复。然而,骨髓间质细胞移植的确切效果还需要进一步研究。     

胰岛素样生长因子对面神经损伤的修复作用

目的探讨局部应用胰岛素样生长因子(IGF-1)对面神经损伤的修复作用.方法将20只成年新西兰兔面神经上颊支切除5mm,在断端间置入硅胶再生室,左右侧随机分组,采用自身对照,在实验耳室内注入IGF-1,对照耳用生理盐水,术后4周和8周进行电生理学、组织病理学观察和形态学定量分析.结果术后4周,两组电刺激面神经很少能引发面肌兴奋,有髓轴索计数,轴索直径和面积t检验,两组差异有显著性意义(P<0.05).术后8周实验耳运动神经传导速度(MCV)明显短于对照耳,有髓轴索计数,轴索直径和面积实验耳大于对照耳(P＜0.05).结论局部应用IGF-1可促进面神经损伤的修复.     

局部应用糖皮质激素对大鼠面神经损伤后修复的影响

目的观察局部应用地塞米松（dexamethasone,Dex）对面神经损伤后再生修复的影响。方法健康雌性SD大鼠63只,建立大鼠面神经横断伤后端端吻合模型,分为生理盐水（normal saline,NS）对照组、地塞米松（Dex）2mg组和Dex5mg组,分别将浸泡于NS、2mg/ml及5mg/ml地塞米松磷酸钠溶液至饱和后的明胶海绵敷于各组动物的端端吻合口处。术后1、2、3、7天取远端近吻合口处神经行劳克坚牢蓝（Luxol Fast Blue,LFB）染色及ED1免疫组化染色,光镜下观察髓鞘和巨噬细胞;术后2、4、8周光镜下（锇酸染色）观察远端相同部位神经再生情况并进行轴突计数。结果光镜下观察,术后第1天髓鞘形态变化不明显,术后第2天出现明显变性崩解,至第3天崩解加快,第7天已见不到完整的髓鞘,仅余部分髓鞘碎片。术后第1天巨噬细胞数量较少,第2天开始增多,第7天较前3天显著增多。三组间髓鞘残余及巨噬细胞数量均无显著性差异（P〉0.05）。术后2周,各组均出现新生髓鞘,三组间轴突计数无统计学差异（P〉0.05）。结论本实验条件下,局部应用小剂量地塞米松对髓鞘清除速度、巨噬细胞及轴突再生数量没有明显影响。     

面神经吻合术手术时机探讨与再生神经纤维研究

目的探讨面神经损伤后最佳修复时机。方法通过对面神经即时吻合和延迟不同时期吻合术后面神经有髓纤维通过率的计算,评价神经再生的效果。同时对再生有髓纤维的髓鞘形态进行电镜观察,计算髓鞘腔面积和髓鞘厚度,对照各组各阶段面神经功能恢复情况,客观评价面神经即时吻合和延迟不同时期吻合术后面神经再生的情况。结果面神经吻合术后2个月检测,正常组、即时缝合组和延迟7 d缝合组的有髓纤维通过率明显高于其他各延迟缝合组（P〈0.05）;即时缝合组和延迟7 d缝合组面神经吻合口远端的髓鞘形态与正常组接近;其他各延迟缝合组面神经吻合口远端的髓鞘形状较不规则,直径小,髓鞘厚度薄,延迟2个月组和延迟3个月组更为明显。结论延迟一段时间修补面神经同样可以得到较好的再生效果。通过对面神经吻合术最佳手术时机的研究,为临床实践提供了理论基础,具有一定临床实际意义。     

Preliminary study of the facial nerve regeneration in the chamber: the influence of myelin basic protein]

OBJECTIVE: To study the role of exogenous myelin basic protein(MBP) in neural repairment. METHODS: Adult New Zealand rabbits were employed in vivo preparation. A 12 microL nerve growth chamber was created by suturing the proximal and distal stumps of a transected facial never (FN) trunk into a tube. The regenerated nerves within the chambers were dissected and fixed for histological studies with light microscope at 4, 6 and 8 weeks respectively following the surgery. RESULTS: Morphological analysis of nerves showed no difference between the MBP and control group in the size of the regeneration FN within the chambers, diameters of myelinated axons, thickness of myelin sheath and number of myelin axons grew into the distal end of chamber at 4 weeks. At 6 and 8 weeks after operation, the MBP group showed a more mature-appearance regenerative nerve comparing to control group. Especially, the enhancement of maturation in the regeneration axons was very noticeable at 6 weeks. CONCLUSION: The study showed that pharmacological administration of exogenous MBP within a chamber at the time of entubational nerve repair enhances regeneration of myelinated axons across the sectioned ends of FN.     

神经生长因子在面神经损伤修复中作用的实验研究

OBJECTIVE: To elucidate the role of NGF in the regeneration of facial nerve. METHODS: The superior buccal division of facial nerve of adult New Zealand rabbit was transected and a nerve growth chamber created. The chamber of the experimental side was filled with NGF/normal saline and that of the control side with normal saline alone. Four and eight weeks after operation, the regenerated nerves in the chambers were dissected for histological studies. RESULTS: Four weeks after operation, the average thickness of myelin sheath and the average number of myelinated axons were 0.779 +/- 0.475 micron, 2.024 +/- 1.999 (n = 11) in experimental group and 0.413 +/- 0.132 micron, 368 +/- 171 (n = 8) in control sides respectively. There was significant difference between the experimental sides and control sides (P < 0.05). Eight weeks after operation, the regenerated nerve appeared more mature. There were significant difference in the average diameters, the thickness of myelin sheath and the number of myelinated axons between the experimental and control sides (P < 0.05). CONCLUSION: NGF within a silicone chamber enhanced facial nerve regeneration in New Zealand rabbits.     

Facial nerve regeneration through semipermeable chambers in the rabbit.

Peripheral neural regeneration, over a 10-mm transectional gap, was determined in 70 rabbit buccal divisions of the facial nerve using two entubational systems (semipermeable and impermeable silicone chambers) prefilled with three natural occurring media (serum, blood, and saline) during a 5-week period. The number of myelinated axonal regenerates at the midchamber and at 2 mm in the distal transected neural stump were counted in each group and compared to pooled myelinated axonal counts in 9 normal rabbit buccal divisions of the facial nerve. Semipermeable porous chambers had an overall greater regeneration success rate (75% vs. 42.8%) and regained, on the average, a higher number of myelinated axons (51.4% vs. 26.1%) than silicone chamber regenerates. Semipermeable chambers prefilled with serum or blood had significantly higher regeneration success rates, myelinated axonal counts, and percentages of neural innervation of the distal transected neural stump. Both entubational systems produced similar axonal counts with intraluminal saline. The highest overall success rate (93.7%) and average number of myelinated axons per chamber (3072) were achieved in semipermeable chambers prefilled with serum. The greatest variability in myelinated axonal counts (0 to 3266 axons) and percentage of distal stump innervation (5.5% to 98.1%) was seen in silicone chambers filled with saline. The percentage of myelinated axons from the midchamber that innervated the distal stump was greater in semipermeable chambers with blood (73%) and serum (54%) than in silicone saline chambers (43%). On the average, the distal stumps from semipermeable chambers filled with serum (47%) and blood (33.5%) regained a higher percentage of normal myelinated axonal counts than silicone-saline chambers (12.5%). These results suggest that both the construction of entubational chamber and the intraluminal medium can have significant influence on neurite regeneration. Semipermeable chambers prefilled with serum have a strong neurite-promoting potential in peripheral neural regeneration of rabbit facial nerves.     

Rabbit facial nerve regeneration in NGF-containing silastic tubes

Previous reports suggest that exogenous nerve growth factor (NGF) enhanced nerve regeneration in rabbit facial nerves.¹ Rabbit facial nerve regeneration in 10-mm Silastic® tubes prefilled with NGF was compared to cytochrome C (Cyt. C), bridging an 8-mm nerve gap. Three weeks following implantation, NGF-treated regenerates exhibited a more mature fascicular organization and more extensive neovascularization than cytochrome-C-treated controls. Morphometric analysis at the midtube of 3- and 5-week regenerates revealed no significant difference in the mean number of myelinated or unmyelinated axons between NGF- and cytochrome-C-treated implants. However, when the number of myelinated fibers in 5-week regenerates were compared to their respective preoperative controls, NGF-treated regenerates had recovered a significantly greater percentage of myelinated axons than cytochrome-C-treated implants (46% vs. 18%, respectively). In addition, NGF-containing chambers reinnervated a higher percentage of myelinated axons in the distal transected neural stumps (49% vs. 34%). Behavioral and electrophysiologic studies demonstrated spontaneous and induced activities in the target muscles when approximately one third of the myelinated axons were recovered in the midchamber (1280 axons). Horseradish peroxidase (HRP) studies demonstrated retrograde axonal transport to the midchamber and proximal transected neural stump. PC12 bioassay demonstrated persistent NGF activity in the intrachamber fluids at 3 (5:1 dilution) and 5 (2:1 dilution) weeks of entubation. Electrophysiologic tests demonstrated a slow conduction velocity of a propagated electrical impulse (43.5 m/s^?1 vs. 67 m/s^?1) and shallow wide compound action potential. In wider defects (15-mm chambers) and longer entubation periods (7 weeks), no regeneration or NGF activity was seen. Therefore, exogenous NGF provides an early but limited neurotrophic effect on the regeneration of the rabbit buccal division of the facial nerve and a limited behavioral and physiological improvement in the target muscles.     

Experimental study on facial nerve regeneration with or without geniculate ganglionectomy

OBJECTIVE: To investigate regeneration of the distal facial nerve following nerve grafting within the tympanic segment with geniculate ganglion preservation or dissection. DESIGN: Randomized controlled trial. SUBJECTS: Twenty-three adult New Zealand albino rabbits were used in this study. INTERVENTIONS: A 2-mm tympanic segment of the facial nerve was removed, and the greater auricular nerve was harvested for grafting in all animals. In group 1 (10 rabbits), the geniculate ganglion was preserved. In group 2 (13 rabbits), the geniculate ganglion was dissected. Mastoidal and extratemporal segments of the facial nerve were harvested 3 months postoperatively for histological examination by electron microscopy. RESULTS: The number of myelinated axons in normal facial nerves was 1819.6 +/- 535.6. In group 1, the number of myelinated axons was 123.6 +/- 31.1, and, compared with normal facial nerves, the diameter of the regenerative axons was decreased and the sheath thickness in the regenerative fiber was diminished. In group 2, the number of myelinated axons was 515.1 +/- 103.1, while the myelin sheath thickness was proportionate to axon diameter. (Data are given as mean +/- SD.) CONCLUSION: Geniculate ganglionectomy may improve motor axon regeneration.     

Evaluation of a new method of neural anastomosis using nitrocellulose paper

Nerve regeneration was examined in 108 mouse sciatic nerves in a prospective morphometric study in which a new anastomotic technique using nitrocellulose paper was compared with conventional suturing and simple sectioning. Mice were randomly allocated to one of the three arms of the trial and sciatic nerves were examined following surgery at time intervals up to 8 weeks. Serial sections were taken for qualitative and quantitative morphometric analyses. Counts demonstrated that the rate of regeneration was faster in the nitrocellulose group than following nerve section alone, but that the suture group was even better. However, 8 weeks after surgery, there were no significant differences in myelinated axon counts 4mm distal to the site of section between any of the experimental groups. The superlative regenerative capacity of rodent axons may limit the applicability of this model to human nerve tissue.     

Evaluation of a new method of neural anastomosis using nitrocellulose paper*

Nerve regeneration was examined in 108 mouse sciatic nerves in a prospective morphometric study in which a new anastomotic technique using nitrocellulose paper was compared with conventional suturing and simple sectioning. Mice were randomly allocated to one of the three arms of the trial and sciatic nerves were examined following surgery at time intervals up to 8 weeks. Serial sections were taken for qualitative and quantitative morphometric analyses. Counts demonstrated that the rate of regeneration was faster in the nitrocellulose group than following nerve section alone, but that the suture group was even better. However, 8 weeks after surgery, there were no significant differences in myelinated axon counts 4 mm distal to the site of section between any of the experimental groups. The superlative regenerative capacity of rodent axons may limit the applicability of this model to human nerve tissue.     

Early stages of facial nerve regeneration through silicone chambers in the rabbit

The early stages of rabbit peripheral facial nerve regeneration [N = 16], over a 10-mm transectional gap, were analyzed at 1, 3, and 5 weeks of buccal nerve entubation in silicone chambers prefilled with saline. Normal nerve pooled data were obtained in nine nerves. Chronologic morphologic and morphometic light and electron microscopic computer-captured data reveal that the regeneration process can be subdivided into four stages: 1. The establishment of an acellular intergap matrix; 2. the ingrowth of mesodermally derived cells (macrophages, fibroblasts, endothelial cells, etc.) to form an intergap scaffolding; 3. the ingrowth of ectodermally derived cells (neurons, Schwann's cells, etc.) to reconstitute the transected peripheral nerve; and 4. neural maturation by progressive axonal enlargement, myelination, and compartmentalization. The first two stages occur during the first week, the third stage during the third week, and the fourth stage from the fifth week onwards of neural entubation. Morphometic analyses indicate that total neuroregenerates increase in number from 303 +/- 286 to 2693 +/- 1334 (+/- values are standard deviations) and myelination of axons increases from 12% to 48% during the third to fifth week of entubation. The thickness of the myelin (g-ratio) increases from 0.89 +/- .01 to 0.74 +/- .06 (SD) during the same period of time. At the end of the fifth week of entubation, the midchambers contain, on the average, 1279 +/- 980 myelinated axons (30% of normal counts) and 483 (+/- 11.2%) axons cross the chambers to innervate the distal transected neural stump (12.5%). Specific target-organ (quadratus labii superioris muscle) activity can be recaptured with a smaller number (12.5%) of regenerating myelinated axons from the buccal division of the facial nerve during the fifth week of entubation.     

Rabbit facial nerve regeneration in autologous nerve grafts after antecedent injury

OBJECTIVE: The effect of incomplete antecedent injuries on subsequent facial nerve regeneration within cable graft repairs is not known. The purpose of this study is to compare facial nerve regeneration after an immediate and delayed neural cable graft repair. METHOD: Rabbit facial nerve regeneration after complete transectional injuries of the buccal division was compared in two experimental models. In one, a 10-mm segment of the nerve was transected, rotated 180 degrees, and immediately repaired as a cable graft (N=8). In the second, a preliminary nerve crush was allowed to recover over a 4-week period and a 10-mm segment of nerve centered on the crush site was then transected, rotated 180 degrees, and delay repaired as a cable graft (N = 7). Data are presented as total numbers of regenerating myelinated axons that traverse the surgical repair to innervate the cable graft and distal nerve stumps, as well as the percentage of regenerating neurites compared with preoperative pooled and individual controls. Subpopulations of regenerating neurons are delineated to quantify the pattern of neural innervation. RESULTS: Five weeks after cable graft repair both groups had similar myelinated outgrowth from the proximal nerve stump across the proximal anastomosis to innervate the cable graft (3995 +/- 1209 vs. 3284 +/- 651; P = .89). However, the delayed repair group had more intrafascicular regeneration within cable grafts (2261 +/- 931 vs. 1660 +/- 1169; P = .02) and distal nerve stump (1532 +/- 281 vs. 445 +/- 120; P = .004) than the immediate repair group. The immediate repair group had greater extrafascicular nerve regeneration in the cable graft (2335 +/- 1954 vs. 437 +/- 236; P = .001) and more myelin and axonal debris in pre-existing neural fascicles of the cable graft (P = .02) and distal nerve stump (463 +/- 187 vs. 103 +/- 87; P = .02). CONCLUSIONS: Antecedent priming lesions do not enhance axonal survival as determined by regenerating myelinated axonal counts. However, antecedent injuries enhance the efficiency of neural innervation of the affected mimetic musculature by increasing the number of myelinated intrafascicular neural regenerants in the cable graft and distal nerve stump. This is accomplished by two factors: increased perineural fibrosis and decreased intrafascicular myelin and axonal debris.