Repair of nerve defect with acellular nerve graft supplemented by bone marrow stromal cells in mice

REPAIR OF NERVE DEFECT WITH ACELLULAR NERVE GRAFTSUPPLEMENTED BY BONE MARROW STROMAL CELLS IN MICE

ZHE ZHAO, M.D., YU WANG, M.D., JIANG PENG, M.D.,* ZHIWU REN, M.D., SHENGFENG ZHAN, M.D.,

YAN LIU, M.D., BIN ZHAO, B.A., QING ZHAO, M.D., LI ZHANG, B.A., QUANYI GUO, M.D., WENJING XU, M.Ed.,

and SHIBI LU, M.D.

The acellular nerve graft that can provide internal structure and extracellular matrix components of the nerve is an alternative for repair ofperipheral nerve defects. However, results of the acellular nerve grafting for nerve repair still remain inconsistent. This study aimed toinvestigate if supplementing bone marrow mesenchymal stromal cells (MSCs) could improve the results of nerve repair with the acellularnerve graft in a 10-mm sciatic nerve defect model in mice. Eighteen mice were divided into three groups (n 5 6 for each group) for nerverepairs with the nerve autograft, the acellular nerve graft, and the acellular nerve graft by supplemented with MSCs (5 3 105) fibrin gluearound the graft. The mouse static sciatic index was evaluated by walking-track testing every 2 weeks. The weight preservation of the tri-ceps surae muscles and histomorphometric assessment of triceps surae muscles and repaired nerves were examined at week 8. Theresults showed that the nerve repair by the nerve autografting obtained the best functional recovery of limb. The nerve repair with the acel-lular nerve graft supplemented with MSCs achieved better functional recovery and higher axon number than that with the acellular nervegraft alone at week 8 postoperatively. The results indicated that supplementing MSCs might help to improve nerve regeneration and func-tional recovery in repair of the nerve defect with the acellular nerve graft. VVC 2011 Wiley-Liss, Inc. Microsurgery 31:388–394, 2011.

The use of nerve autografts is the clinical ‘‘gold standard’’

for repair of a peripheral nerve defect.1 However, the appli-

cation of the nerve autograft is limited by availability of do-

nor sites, additional surgery, size mismatch, and donor site

morbidity. Therefore, alternatives for repair of nerve defect

are needed. An ideal nerve graft alternative should have a

similar structure and composition as that being replaced.

The acellular nerve graft, providing internal structure and

extracellular matrix components of the nerve, is an alterna-

tive to the nerve autograft for repair of short nerve defects,

and has been studied experimentally.2,3 However, the

results remain inconsistent.4–6 Various efforts for improv-

ing results of this technique have been attempted.

Mesenchymal stromal cells (MSCs) are pluripotent

stem cells that localize in the stromal compartment of the

bone marrow and can easily be obtained and cultured.7

Experimental studies have shown that MSCs injected into

injured nerves can improve growth and myelination of

regenerating axons.8–10 In this study, we investigated if

application of the fibrin glue containing MSCs around the

acellular nerve graft would improve nerve regeneration

when use of this acellular nerve graft to repair the nerve

defect in mice.

MATERIALS AND METHODS

Animals

Twelve adult male Balb/c and 21 C57/BL6 mice

(Vitalriver, China) weighing 25 and 30 g were used in

the study. The experimental protocol was approved by

the institutional care and use committee of our institution.

The animals were placed in a temperature- and humidity-

controlled room with a 12-hours light/12-hours dark cycle

and allowed free access to standard mouse chow and water.

MSCs Preparation

Primary cultured MSCs were obtained from three adult

C57/BL6 mice as previously described.11 Briefly, mice

were given a lethal dose of phenobarbital, and the tibias

and femurs were removed. A 22-gauge needle filled with

Dulbecco’s modified Eagle’s medium (DMEM) was used

to flush out whole bone marrow. The recovered cells were

then plated in DMEM supplemented with 10% fetal bovine

serum and penicillin–streptomycin in 25-cm2 tissue-culture

flasks. After 24 hours, the nonadherent cells were removed

and the culture medium was completely replaced. MSCs

were used at passage 2. An amount of 5 3 106 of MSCs

was diluted with 500 ll fibrinogen plus potassium dihydro-

gen phosphate. One syringe was filled with this solution

and another with 500 ll thrombin plus calcium chloride.

The 2 syringes were connected to a Y-piece for injection.

Preparation of Acellular Nerve Graft

Twelve Balb/c mice were sacrificed by intraperitoneal

injection with sodium pentobarbital (0.3 ml, 60 mg/ml).

Orthopedic Research Institute of Chinese PLA, General Hospital of ChinesePLA, Beijing 100853, People’s Republic Of ChinaZhe Zhao and Yu Wang contributed equally to this work.Grant sponsor: The Hi-Tech Research and Development Program of China(863 Program); Grant number: 2009AA03Z312; Grant sponsor: MedicalHealth Research Foundation Project of Chinese PLA; Grant number: 06Z057;Grant sponsor: Key Projects in the National Science and Technology PillarProgram; Grant number: 2009BAI87B02; Grant sponsor: National NaturalScience Foundation of China; Grant number: 30571875.

*Correspondence to: Professor Jiang Peng, M.D., Orthopedic ResearchInstitute of Chinese PLA, General Hospital of Chinese PLA, Fuxing Road 28,Haidian District, Beijing 100853, People’s Republic of China.E-mail: [email protected]

Received 26 July 2010; Accepted 13 December 2010

Published online 18 April 2011 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/micr.20882

VVC 2011 Wiley-Liss, Inc.

The sciatic nerves were harvested and cleaned. The acel-

lular grafts were prepared as described,3 with modifica-

tion. The harvested sciatic nerves were immersed in the

distilled water, which was replaced several times during

2 hours, then replaced with a solution containing 0.3%

Triton X-100 (Sigma, St. Louis, MO) in distilled water,

followed by 2-hours agitation in a solution of 0.4% so-

dium deoxycholate (Sigma) in the distilled water. The

extraction procedure was then repeated. Finally, tissue

segments were washed three times for 15 minutes each in

PBS, irradiated for 12 hours with Co60 for sterilization

and stored in PBS at 48C. Six acellular nerve segments

were randomly chosen for the nuclei Hoechst staining

(bis-benzimide Hoechst 33258 pentahydrate; Molecular

Probes, Eugene, OR).

Experimental Design and Surgical Procedures

Eighteen C57/BL6 mice were divided into three

groups (n 5 6 for each group). In group of nerve repair

with the nerve autograft, the sciatic nerve on the mouse’s

left leg was exposed under general anesthesia with so-

dium pentobarbital (60 mg/ml, 0.2 ml). A 10-mm-long

sciatic nerve segment from the mid-thigh level was

resected and subsequently sutured back into the nerve by

two epineurial stitches with 12–0 Ethilon suture at each

repair site. In group of nerve repair with the acellular

nerve allograft supplemented with MSCs, a 7-mm seg-

ment was resected and replaced with a prepared 10-mm-

long acellular nerve allograft with the same technique. A

volume of 0.1 ml fibrin glue containing 5 3 105 MSCs

was injected around the graft (Fig. 1). In group of nerve

repair with for the acellular nerve allograft, only 0.1 ml

fibrin glue was injected, as the control. The wound was

then closed in layers. The mice were allowed for recov-

ery from surgery. On the day before surgery and at

weeks 2, 4, 6, and 8 postoperatively, mice underwent a

walking-track test. At week 8 postoperatively, all mice

were euthanized by lethal dose of intraperitoneally

injected sodium pentobarbital, and triceps surae muscles

and nerves were harvested for muscle weight measure-

ments and histomorphometric assessments. The nerves

and muscles from the contralateral healthy side were ran-

domly chosen from two mice in each group, as the nor-

mal control. All assessments were done in blind-test fash-

ion by the investigator and a pathologist.

Walking-Track Test

The mouse static sciatic index (SSIm) score was cal-

culated as previously described.12 Two measurements

were obtained from the walking-track test: the distance

between the first and the fifth toes (toe spread, TS), and

the distance between the tip of the third toe and the most

posterior part of the foot in contact with the ground (print

length, PL). The estimated TS and PL were used to gen-

erate the TS factor (TSF) and PL factor (PLF) (factor 5experimental value-normal value/normal value) for calcu-

lation of SSIm based on the formula: SSIm 5 101.3 3TSF-54.03 3 PLF-9.5.

Triceps Surae Muscle Weight Measurement and

Masson Trichrome Staining

The triceps surae muscles from the experimental and

contralateral sides were harvested and weighed. The mus-

cle weight preservation of experimental side was calcu-

lated as a percentage of the contralateral side. Then the

muscle specimens were fixed in 4% paraformaldehyde

and sectioned with Masson trichrome staining. The

images of muscle sections were photographed by use of a

color digital camera (Olympus BX51). Five sections were

randomly taken from each sample, with five fields viewed

for each section. The data for the cross-sectional area

number of the gastrocnemius muscle fibers were

Figure 1. Repair of the sciatic nerve defect with the acellular nerve graft supplemented by injection of fibrin glue containing MSCs around

the graft. A: Model; B: Intraoperative view. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

Acellular Nerve Graft by Stromal Cells 389

Microsurgery DOI 10.1002/micr

measured by use of Image Pro Plus (Media Cybernetics,

Bethesda, MD).

Histomorphometric Assessment

The distal sciatic nerve (3 mm distal to the graft) was

harvested. The specimens were fixed in 2% glutaralde-

hyde for 2 days, dehydrated and plastic-embedded. Trans-

verse sections of 0.5 lm and 70 nm (ultrathin) were

obtained by use of an ultramicrotome. The sections of

0.5 lm thick were stained with 1% toluidine blue. Images

were acquired by use of a light microscope (Olympus

BX51) connected to a digital camera. The morphological

changes and total number of nerve fibers were examined

and counted under a 4003 magnification. The ultrathin

70-nm sections were stained with the contrast agents 1%

uranyl acetate and lead citrate, and examined under a

Philips CM120 transmission electron microscope

equipped with an image acquisition system with a 80003magnification for measurement of diameters of myelin-

ated fibers, thickness of myelin sheaths and G-ratios (ra-

tio of axon diameter to fiber diameter). Photographs from

10 random fields of each ultrathin nerve section were an-

alyzed by use of Image Pro Plus.

Statistical Analysis

The results are expressed as means 6 standard devia-

tions (SD). Statistical comparisons involved use of one-

way ANOVA and Kruskal-Wallis test with SPSS v13.0

(SPSS Inc., Chicago, IL). A P < 0.05 was considered

statistically significant.

RESULTS

Hoechst Staining

Hoechst 33258 staining revealed the presence of cells

in normal nerves before decellularization (Fig. 2A). No

cells or cell fragments were observed in decellularized

nerve grafts (Fig. 2B), but integrated basal membrane of

nerve was preserved.

Static Sciatic Index

All mice survived from surgery. The results of walk-

ing-track tests showed that the functional recovery of

limb was better in mice that underwent nerve repair with

the nerve autograft when compared to nerve repair with

acellular nerve grafts with or without MSCs from postop-

erative weeks 2–8 (Fig. 3). At postoperative week 8, the

SSIm score from the nerve autograft group (211.96 62.67) was significantly higher than that from the acellular

nerve graft group (221.76 6 3.39) and the group of acel-

lular nerve graft supplemented with MSCs (219.34 63.39; P < 0.05).

Figure 2. A Hoechst 33,258 staining for cell nuclei of (A) normal sciatic nerve and (B) the acellular nerve graft. Scale bar, 100 lm. [Color

figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

Figure 3. Static sciatic index scores from walking-track test in

mice. ANG: acellular nerve graft; MSC: mesenchymal stromal cells.

[Color figure can be viewed in the online issue, which is available

at wileyonlinelibrary.com.]

390 Zhao et al.


Weight Preservation of Triceps Surae Muscles and

Morphometric Analysis

The results of triceps surae muscle weight preserva-

tion from different groups are shown in Table 1. The

mean muscle weight from the group with the nerve repair

by the acellular nerve graft supplemented with MSCs was

significantly higher than that from the nerve repair with

the acellular nerve graft alone (P < 0.01). However, the

muscle preservation from both acellular nerve graft

groups with and without supplementing MSCs was sig-

nificantly lower than that from the nerve autograft group

(P < 0.01). The triceps surae muscle fiber number in the

group of acellular nerve graft supplemented with MSCs

was significantly higher than the nerve autograft group (P< 0.05), but lower than the group with acellular nerve

graft alone (P < 0.05; Table 1; Fig. 4).

Morphometry of the Sciatic Nerve

The toluidine blue staining showed that the nerve

repaired with the nerve autograft appeared with slightly

smaller and thinner myelinated axons than the healthy

nerve (Fig. 5). In the nerve repaired with the acellular

nerve graft supplemented with MSCs, the diameter of

myelinated fibers and thickness of myelin sheaths were

Table 1. Histological Assessment at 8 Postoperative Weeks

Group

Weight preservation

of triceps surae

muscle (%)

Number of

triceps surae

muscle fibers

Total number

of nerve

fibers

Myelinated

fiber diameter

(lm)

Myelin sheath

thickness (lm) G-ratio

Normal nerve (n 5 6) – 331 6 50** 3252 6 116** 5.30 6 1.60** 1.00 6 0.29** 0.62 6 0.04

Nerve Autograft (n 5 6) 79.15 6 4.69** 405 6 76** 1698 6 458** 3.21 6 1.40** 0.43 6 0.11** 0.67 6 0.09

Acellular nerve graft (n 5 6) 43.30 6 5.11** 645 6 41** 624 6 245* 3.29 6 0.77** 0.34 6 0.06** 0.73 6 0.04

Acellular nerve

graft þ MSCs (n 5 6)

61.91 6 5.38 512 6 28 923 6 205 4.26 6 1.29 0.54 6 0.10 0.70 þ 0.09

*P < 0.05 and **P < 0.01: compared to nerve repair with the acellular nerve graft supplemented with MSCs

Figure 4. Triceps surae muscles. Masson trichrome staining sections from (A) healthy side; (B) nerve repair with the nerve autograft; (C)

nerve repair with the acellular nerve graft; and (D) nerve repair with the acellular nerve graft supplemented with MSCs. Scale bar, 50 lm.

[Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]



significantly larger than that in repair with the acellular

nerve graft alone (P < 0.01). The nerve repaired with the

acellular nerve graft alone showed fewer myelinated

axons and more connective tissue. Under transmission

electron microscope, the diameter of myelinated fibers

and thickness of myelin sheaths of the nerve repaired

with the acellular nerve graft supplemented with MSCs

were significantly greater than the nerve repaired with

acellular nerve graft alone (P < 0.01; Fig. 6; Table 1).

However, G-ratio values did not show statistically signifi-

cantly different between groups. The mean total number

of nerve fibers in the nerve repaired with the nerve auto-

graft (1698 6 458) was significantly higher than the

nerves repaired with the acellular nerve graft with and

without supplementing MSCs (923 6 205, 624 6 245;

P < 0.01).

DISCUSSION

Chemical acellularization of peripheral nerves not

only reduces the cellular and humoral immunologic

response, such as immunoreaction to Schwann cells and

myelin, but also retains internal structure and extracellu-

lar matrix components of the nerve, which are necessary

for nerve regeneration.4,13,14

It has been known that neurotrophic factors support neu-

ronal survival and axonal elongation.15 Our previous studies

showed that supplementing such factors around acellular

nerve grafts improved nerve regeneration.6,16 However, the

results remained inconsistent, which may be attributed to

inadequate doses, undesired initial burst release of factor at

the optimal location, or the use of single growth factors

rather than multiple factors as it occurs naturally.

Figure 5. The distal sciatic nerve (3 mm distal to the graft). Toluidine blue staining sections from (A) normal sciatic nerve; (B) nerve repair

with the nerve autograft; (C) nerve repair with the acellular nerve graft; and (D) nerve repair with the acellular nerve graft supplemented

with MSCs. Scale bar, 50 lm. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

392 Zhao et al.


Experimental and clinical studies have provided evi-

dence that MSC-based nerve-tissue engineering can posi-

tively affect functional recovery of repair of nerve

defects.17 MSCs can produce many different cytokines

and growth factors that have been proved a positive

effect on nerve regeneration.14 Experimental studies have

shown that MSCs may also relay and magnify the neuro-

trophic function from MSCs to Schwann cells in addition

to direct secretion of neurotrophic factors.18 The MSCs-

conditioned medium was found to enhance axonal growth

and neurogenesis in cultured rat dorsal root ganglia

explants, and promote cell survival, proliferation and neu-

rotrophic factor expression in cultured rat Schwann

cells.19 In addition, bone-marrow MSCs are easily

accessed by aspirating the bone marrow and expanded in

vitro, which is a great advantage for clinical use.

In this study, we used the fibrin glue as a temporary

extracellular matrix for the transplanted cells.20 Experi-

mental studies showed that neurotrophic factors could be

released rapidly from fibrin glue,21 and the bioactivity of

cells was not influenced by the fibrin glue.22 Pan et al.22

reported the fibrin matrix could be maintained for 7–10

days before degradation, thus allowing time for the trans-

planted cells to produce neurotrophic factors and facilitate

nerve regeneration in a sciatic nerve crush injury model.

We found that MSCs could survive and proliferate in

fibrin glue up to 3 weeks in cells culture (data not

shown). The long-term survival of transplanted cells in

fibrin glue needs further study.

Wang et al.4 combined an acellular allogenic nerve

graft and autologous bone MSCs for repair of peripheral

nerve defects in primates. MSCs were injected through the

full length of the nerve graft by a micro-injector. The

nerve grafts were then cultured for 48 hours before in vivo

experiments. They found that the acellular nerve graft

injected with MSCs provided a favorable environment for

the growth and myelination of regenerating axons. How-

ever, compared to direct injection of MSCs into the acellu-

lar nerve graft, supplying MSCs in fibrin glue around the

acellular nerve graft was easier to perform and avoid dam-

aging the nerve structure, and could also support nerve

regeneration, as the results shown in this study.

In this study, we used SSIm to evaluate the functional

recovery after nerve repair. The SSIm from the group of

nerve repair with the acellular nerve graft supplemented

with MSCs was significant improved when compared to

the nerve repair with the acellular nerve graft alone,

although functional recovery from this group was still

lower than the nerve repair with the nerve autograft. Gu

et al.23 demonstrated that fetal neural stem cells trans-

planted into peripheral nerves could differentiate into

neurons and form functional neuromuscular junctions

with denervated muscle, which may be beneficial for the

treatment of muscle atrophy after peripheral nerve injury.

We also found that the acellular nerve graft supplemented

with MSCs for nerve repair could maintain the muscle

weight, which was attributed to early reinnervation.

Although the mean total number of nerve fibers in the

nerve repaired with the acellular nerve graft supple-

mented with MSCs was significant lower than the repair

with the nerve autograft, the acellular nerve graft supple-

mented with MSCs produced a higher number of axons

and greater axonal diameter and myelin thickness while

compared with the acellular nerve graft alone, which

indicates that MSCs were beneficial for improve maturity

of myelinated axon. The G-ratio is widely used as a func-

tional and structural index of optimal axonal myelina-

tion.24 We found no difference between groups in G-ra-tio, which may show that the anticipated reduced amount

of myelination would be reflected in an increase in the

G-ratio of fibers.

In conclusion, this study proved that supplementing

MSCs around the acellular nerve graft could improve

nerve regeneration and functional recovery when use of

this graft to repair the nerve defect in mice. Future inves-

tigation is needed to study mechanisms and determine the

Figure 6. The distal sciatic nerve (3 mm distal to the graft). Ultrathin sciatic sections from (A) nerve repair with the nerve autograft; (B)

nerve repair with the acellular nerve graft; and (C) nerve repair with the acellular nerve graft supplemented with MSCs. Scale bar, 2 lm.



condition to optimize this technique in improving nerve

regeneration when used for nerve repair.

REFERENCES

1. Siemionow M, Sonmez E. Nerve allograft transplantation: a review.J Reconstr Microsurg 2007;23:511–520.

2. Kim BS, Yoo JJ, Atala A. Peripheral nerve regeneration using acel-lular nerve grafts. J Biomed Mater Res A 2004;68:201–209.

3. Sondell M, Lundborg G, Kanje M. Regeneration of the rat sciaticnerve into allografts made acellular through chemical extraction.Brain Res 1998;795:44–54.

4. Wang D, Liu XL, Zhu JK, Jiang L, Hu J, Zhang Y, Yang LM,Wang HG, Yi JH. Bridging small-gap peripheral nerve defects usingacellular nerve allograft implanted with autologous bone marrowstromal cells in primates. Brain Res 2008;1188:44–53.

5. Walsh S, Biernaskie J, Kemp SW, Midha R. Supplementation ofacellular nerve grafts with skin derived precursor cells promotes pe-ripheral nerve regeneration. Neuroscience 2009;164:1097–1107.

6. Li Z, Peng J, Wang G, Yang Q, Yu H, Guo Q, Wang A, Zhao B,Lu S. Effects of local release of hepatocyte growth factor on periph-eral nerve regeneration in acellular nerve grafts. Exp Neurol2008;214:47–54.

7. Phinney DG, Prockop DJ. Concise review: mesenchymal stem/multi-potent stromal cells: the state of transdifferentiation and modes oftissue repair-current views. Stem Cells 2007;25:2896–2902.

8. Cuevas P, Carceller F, Garcia-Gomez I, Yan M, Dujovny M. Bonemarrow stromal cell implantation for peripheral nerve repair. NeurolRes 2004;26:230–232.

9. Goel RK, Suri V, Suri A, Sarkar C, Mohanty S, Sharma MC, YadavPK, Srivastava A. Effect of bone marrow-derived mononuclear cellson nerve regeneration in the transection model of the rat sciaticnerve. J Clin Neurosci 2009;16:1211–1217.

10. Ribeiro-Resende VT, Pimentel-Coelho PM, Mesentier-Louro LA,Mendez RM, Mello-Silva JP, Cabral-da-Silva MC, de Mello FG, deMelo Reis RA, Mendez-Otero R. Trophic activity derived from bonemarrow mononuclear cells increases peripheral nerve regenerationby acting on both neuronal and glial cell populations. Neuroscience2009;159:540–549.

11. Deng J, Petersen BE, Steindler DA, Jorgensen ML, Laywell ED.Mesenchymal stem cells spontaneously express neural proteins in

culture and are neurogenic after transplantation. Stem Cells2006;24:1054–1064.

12. Baptista AF, Gomes JR, Oliveira JT, Santos SM, Vannier-SantosMA, Martinez AM. A new approach to assess function after sciaticnerve lesion in the mouse-adaptation of the sciatic static index.J Neurosci Methods 2007;161:259–264.

13. Rovak JM, Bishop DK, Boxer LK, Wood SC, Mungara AK, CedernaPS. Peripheral nerve transplantation: the role of chemical acellulari-zation in eliminating allograft antigenicity. J Reconstr Microsurg2005;21:207–213.

14. Totey S, Pal R. Adult stem cells: a clinical update. J Stem Cells2009;4:105–121.

15. Yin Q, Kemp GJ, Frostick SP. Neurotrophins, neurones and periph-eral nerve regeneration. J Hand Surg [Br] 1998;23:433–437.

16. Yu H, Peng J, Guo Q, Zhang L, Li Z, Zhao B, Sui X, Wang Y, XuW, Lu S. Improvement of peripheral nerve regeneration in acellularnerve grafts with local release of nerve growth factor. Microsurgery2009;29:330–336.

17. Chopp M, Li Y. Treatment of neural injury with marrow stromalcells. Lancet Neurol 2002;1:92–100.

18. Wang J, Ding F, Gu Y, Liu J, Gu X. Bone marrow mesenchymalstem cells promote cell proliferation and neurotrophic function ofSchwann cells in vitro and in vivo. Brain Res 2009;1262:7–15.

19. Yang J, Wu H, Hu N, Gu X, Ding F. Effects of bone marrow stro-mal cell-conditioned medium on primary cultures of peripheral nervetissues and cells. Neurochem Res 2009;34:1685–1694.

20. Christman KL, Vardanian AJ, Fang Q, Sievers RE, Fok HH, Lee RJ.Injectable fibrin scaffold improves cell transplant survival, reducesinfarct expansion, and induces neovasculature formation in ischemicmyocardium. J Am Coll Cardiol 2004;44:654–660.

21. Yu H, Peng J, Sun H, Xu F, Zhang L, Zhao B, Sui X, Xu W, Lu S.[Effect of controlled release nerve growth factor on repairing periph-eral nerve defect by acellular nerve graft]. Zhongguo Xiu Fu ChongJian Wai Ke Za Zhi 2008;22:1373–1377.

22. Pan HC, Cheng FC, Chen CJ, Lai SZ, Lee CW, Yang DY, ChangMH, Ho SP. Post-injury regeneration in rat sciatic nerve facilitatedby neurotrophic factors secreted by amniotic fluid mesenchymalstem cells. J Clin Neurosci 2007;14:1089–1098.

23. Gu S, Shen Y, Xu W, Xu L, Li X, Zhou G, Gu Y, Xu J. Application offetal neural stem cells transplantation in delaying denervated muscle atro-phy in rats with peripheral nerve injury. Microsurgery 2010;30:266–274.

24. Chomiak T, Hu B. What is the optimal value of the g-ratio for my-elinated fibers in the rat CNS? A theoretical approach. PLoS One2009;4:e7754.

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Repair of nerve defect with acellular nerve graft supplemented by bone marrow stromal cells in mice

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