Ultrastructural Changes in Spinal Motoneurons and Locomotor Functional Study after Sciatic Nerve Repair in Conduit Tube


1 Cellular and Molecular Research Centre, Department of Anatomy, Faculty of Medicine, Yasouj University of Medical Sciences, Yasouj, Iran

2 Department of Anatomy, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran

3 Department of Physiology, Faculty of Medicine, Yasouj University of Medical Sciences, Yasouj, Iran


Motor deficit and neuron degeneration is seen after nerve transection. The aim of this study is to determine whether a poled polyvinelidene fluoride (PVDF) tube with other supportive strategies can protect the neuronal morphology and motor function after sciatic nerve transaction in rats.
Materials and Methods
After transection of the left sciatic nerve in 60 male Wistar rats (200-250 g), the epineural group was sutured end to end. In the autograft rats, a 10 mm piece of sciatic nerve was rotated 180 °C and sutured back into the nerve gap. In the nerve guidance channel (NGC) group, polarized piezoelectric PVDF tube containing NGF and collagen gel was sutured in the gap. In control group sciatic nerve was removed (10 mm) without repair. After one, four and eight weeks, the L4-L6 spinal cord segment was removed for histological study using transmission electron microscope. Functional outcome was assessed using the Basso, Bresnahan and Beattie (BBB) locomotor scale at both four and eight weeks after the lesion.
Chromatin condensation was seen after 4 weeks in the repair groups. Cell membrane shrinkage and mitochondrial degeneration was observed after 4 and 8 weeks respectively, in the autografted and NGC rats. In the control group, chromatin condensation, cell membrane shrinkage with mitochondrial degeneration and vacuolization of perikaryon was seen after 1, 4 and 8 weeks, respectively. At 56 days, the functional recovery of the epineural rats significantly increased in comparison to the other groups (P< 0.05).
The epineural suture has more efficacies, and NGC may be used as a proper substitute for autograft in nerve injury.


1. Azizzadeh Delshad A, Taki Tiraihi T, Heshmati M. Temporal correlation of bax expression and axotomy-induced motoneuronal apoptosis in adult rats: A morphometric, ultrastructural and immunohistochemical study. Iran J Pathol 2008; 3:67-74.
2. Lin YL, Jen JC, Hsu SH, Chiu IM. Sciatic nerve repair by microgrooved nerve conduits made of chitosan-gold nanocomposites. Sur Neurol  2008; 70:9–18.
3. Chaudhry V, Glass JD, Griffin JW. Wallerian degeneration in peripheral nerve disease. Neurol Clin 1992; 10:613-627.
4. Tae- Kim Y, Haftel VK, Kumar S, Bellamkonda RV. The role of aligned polymer fiber-based constructs in the bridging long peripheral nerve gaps. Biomaterials 2008; 29:3117–3127.
5. Seggio AM, Narayanaswamy A, Roysam B, Thompson DM. Self-aligned Schwann cell monolayers demonstrate an inherent ability to direct neurite outgrowth. J Neural Eng 2010; 7: 046001.
6. Neubauer D, Graham JB, Muir D. Nerve grafts with various sensory and motor fiber compositions are equally effective for the repair of a mixed nerve defect. Exp Neurol 2010; 223:203-206.
7. Payne CE, Hunt SP, Lamberty GH. Primary sciatic nerve repair using titanium staples. Br J Plast Surg  2002; 55:330-334.
8.  Aebischer P, Salessiots JM, Winn SR. Basic fibroblast growth factor released from synthetic guidance channels facilitates regeneration across long nerve gaps. J Neurosci Res 1989; 23:282–289.
9. Jiang X, Lim SH, Mao HQ, Chew SY. Current applications and future perspectives of artificial nerve conduits. Exp Neurol 2010; 223:86–101.
10. Reed AM, Gliding DK. Biodegradable polymers for use in surgery: poly (glycolic)/poly (lactic acid) homo and copolymers, 2: in vitro degradation. Polymer ? 1981; 22:494–498.
11. Evans GR, Brandt K, Katz S, Chauvin P, Otto L, Bogle M, et al. Bioactive poly(l-lactic) conduits seeded with Schwann cells for peripheral nerve regeneration. Biomaterials 2002; 23:841–848.
12. Cai J, Peng X, Nelson KD, Eberhart R, Smith GM. Permeable guidance channels containing microfilament scaffolds enhance axon growth and maturation. J Biomed Mater Res  2005; 75:374–386.
13. Itoh S, Takakuda K, Kawabata S, Aso Y, Kasai K, Itoh H, et al. Evaluation of cross-linking procedures of collagen tubes used in peripheral nerve repair. Biomaterials 2002; 23:4475–4481.
14. Mersa B, Agir H, Aydin A. Sen C Comparison of expanded polytetrafluoroethylene (ePTFE) with autogenous vein as a nerve conduit in rat sciatic nerve defects. Kulak Burun Bogaz Ihtis Derg 2004; 13:103-111.
15. Fine EG, Valentini RF, Bellamkonda R, Aebischer P. Improved nerve regeneration through piezoelectric vinyIidenefluoride- trifluoroethylene copolymer guidance channels. Biomaterials 1992; 13:183-190.
16. Basso DM, Beattie MS, Bresahan JC. A sensitive and reliable locomotor rating scale for open field testing in rats. J Neurotrauma 1995; 12:1-21.
17. Dinh P, Hazel A, Palispis W, Suryadevara S, Gupta R, Diaz-Ruiz A. functional assessment after sciatic nerve injury in a rat model. Neurosci Lett 1999; 266:61-64.
18. Belkas JS, Shoichet MS, Midha R. Peripheral nerve regeneration through guidance tubes.  Neurol Res 2004; 26:151–160.
19. Miyamoto Y. Experimental study of results of nerve suture under tension vs. nerve grafting. Plast Reconstr Surg 1979; 64:540–549.
20. Itoh S, Takakuda K, Kawabata S, Aso Y, Kasai K, Itoh H, et al. Evaluation of cross-linking procedures of collagen tubes used in peripheral nerve repair. Biomaterials 2002; 23:4475–4481.
21. Matsuyama T, Mackay M, Midha R. Peripheral nerve repair and grafting techniques: a review. Neurol Med Chir (Tokyo) 2000; 40:187–199.
22. Valentini RF, Vargo TG, Gardella JA, Aebischer P. Electrically charged polymeric substrates enhance nerve fiber outgrowth in vitro. Biomaterials 1992; 12:775-780.
23. Newsome RW, Andre EY. Measurement of the pyroelectric coefficient of polyvinylidene fluoride. down to 3 k. Physical Rev 1997; 55:7265-7271.
24. Sears TA. Structural changes in intercostals motoneurones following axotomy. J Exp Biol 1987; 132:93-109.
25. Desouza FI, Zumiotti AV, Silva CF. Neuregulins 1-alpha and1-beta on the regeneration the peripheral nerves. Acta Ortop Bras 2010; 18:250-254.
26. Zhang L, Cao R, Zhu Y, Feng G, Zhang X, Huang F. Repair of the peripheral nerve defect with the combination of allogeneic nerve and autologous neuroma. Turk Neurosurg 2010; 20:470-479.
27. Toba T, Nakamura T, Lynn AK, Matsumoto K, Fukuda S. Evaluation of peripheral nerve regeneration across an 80-mm gap using a polyglycolic acid (PGA)–collagen nerve conduit filled with laminin-soaked collagen sponge in dogs. Int J Artif 2002; 25:230–237.
28. Madduri S, Feldman K, Tervoort T, Papaloizos M, Gander B. Collagen nerve conduits releasing the neurotrophic factors GDNF and NGF. J Control Rel 2010; 143:68-74.
29. Yoshii S, Okam M. Collagen filaments as a scaffold for nerve regeneration. J Biomed Mater Res 2001; 56:400–405.