OBJECTIVE: This study investigates the effect of valproic acid (VPA) on expression of neural stem/progenitor cells (NSPCs) in a rat spinal cord injury (SCI) model. METHODS: Adult male rats (n=24) were randomly and blindly allocated into three groups. Laminectomy at T9 was performed in all three groups. In group 1 (sham), only laminectomy was performed. In group 2 (SCI-VPA), the animals received a dose of 200 mg/kg of VPA. In group 3 (SCI-saline), animals received 1.0 mL of the saline vehicle solution. A modified aneurysm clip with a closing force of 30 grams was applied extradurally around the spinal cord at T9, and then rapidly released with cord compression persisting for 2 minutes. The rats were sacrificed and the spinal cord were collected one week after SCI. Immunohistochemistry (IHC) and western blotting sample were obtained from 5 mm rostral region to the lesion and prepared. We analyzed the nestin immunoreactivity from the white matter of ventral cord and the ependyma of central canal. Nestin and SOX2 were used for markers for NSPCs and analyzed by IHC and western blotting, respectively. RESULTS: Nestin and SOX2 were expressed significantly in the SCI groups but not in the sham group. Comparing SCI groups, nestin and SOX2 expression were much stronger in SCI-VPA group than in SCI-saline group. CONCLUSION: Nestin and SOX2 as markers for NSPCs showed increased expression in SCI-VPA group in comparison with SCI-saline group. This result suggests VPA increases expression of spinal NSPCs in SCI.
Aneurysm ; Animals ; Blotting, Western ; Ependyma ; Immunohistochemistry ; Intermediate Filament Proteins ; Laminectomy ; Male ; Nerve Tissue Proteins ; Neurons ; Rats ; Spinal Cord ; Spinal Cord Injuries ; Valproic Acid

OBJECTIVETo determine cell proliferation and nestin expression in the ependyma of adult rat spinal cord after injury.

METHODSRat spinal cord injury models were established by aneurysm clip compression, and nestin expression and proliferation of ependymal cells at different times were shown with pathological and immuno-histochemical staining.

RESULTSEpendymal cells adjacent to the injured site demonstrated a dramatic increase in nestin expression 24 hours after compression. Proliferating cell nuclear antigen was positive, and significant proliferation was observed after 7 days. Nestin expression was down regulated as time went by.

CONCLUSIONNormally quiescent mature ependymal cells appear to revert to an embryonic state in response to spinal cord injury.

Animals ; Cell Division ; Ependyma ; cytology ; metabolism ; Immunohistochemistry ; Intermediate Filament Proteins ; biosynthesis ; Male ; Nerve Tissue Proteins ; Nestin ; Rats ; Rats, Wistar ; Spinal Cord Injuries ; metabolism ; pathology

The potential for nerve regeneration and recovery of its function exists in the presence of a suitable pathway for regenerating axon and endoneurial tube can serve as nerve conduit for regenerating axon in fresh nerve graft. But value of degenerated nerve as donor nerve has not been established till now. This experiment assessed the chronologic influence of fresh and degenerated nerve graft on axonal growth for 10mm gap of sciatic nerve in rabbit and how long degenerated nerve was ahle to serve as a nerve conduit microscopically. Electromicroscopically, the regenerating axons which were ohserved in the degenerated nerve graft had more abundant unmyelinated fibers and revealed abundant collagen fibers in the endoneurium. And these regenerating axons became gradually surrounded with newly developed basal lamina and decreased the collagen fibers at l2 week of degenerated nerve graft. Histologically, myelinated axons which were observed in central area of the degenerated nerve graft at 8 week of degenerated nerve graft were relatively thinner, but a definite structural difference of regenerating axons was not found except reduction of number compared with those of tresh nerve graft. The numher of myelinated axons was 6,072+/-l42 in normal sciatic nerve, 4,479+/- 157 in fresh nerve graft group, and 2,968+/-168 in the degenerated nerve graft group. Difference of the number of myelinated axons between fresh and degenerated nerve graft group was significant stati stically(P<0.05). These results showed that the ability of a degenerated nerve graft as a passage for the regenerating axons and it can be employed as one of the favorable nerve conduits.
Axons ; Basement Membrane ; Collagen ; Humans ; Myelin Sheath ; Nerve Regeneration ; Peripheral Nerves ; Sciatic Nerve* ; Tissue Donors ; Transplants*

In 1999 Kayikcioglu and his colleagues invented the oblique nerve coaptation technique which increases coaptation surface and proved that their technique is superior to conventional vertical coaptation technique. This method is useful but it is not fit for a clinical application because the sciatic nerve was cut obliquely and repaired immediately in their experiment. In that case, we couldn't exclude the possibility of the improved effect by increased orientation of nerve fiber. Using different nerves we could exclude the effect by orientation improvement and prove the superiority of the oblique nerve coaptation technique in functional restoration. Ten Sprague-Dawley rats were used. The tibial nerve and the peroneal nerve were cut randomly to 30 degree and 90 degree on each side. The distal stump of the tibial nerve and the proximal stump of the peroneal nerve were repaired with 10-0 nylon under microscopic view. 12 weeks after nerve coaptation, nerve conduction velocity of extensor digitorum longus muscle, moist weight and histological analysis of extensor digitorum longus muscle, and myelinated axonal count and histological analysis of peroneal nerve were investigated. The results showed the nerves of oblique coaptation(30 degree transection angle) group are more regenerated than those of vertical coaptation(90 degree transection angle) group and nerve conduction velocity and moist weight of extensor digitorum longus muscle are also increased in oblique coaptation group. From these results we came to a conclusion that the oblique nerve coaptation technique is superior to the conventional technique and may be helpful in innervated free flap or nerve graft.
Axons ; Free Tissue Flaps ; Myelin Sheath ; Nerve Fibers ; Neural Conduction ; Nylons ; Peroneal Nerve ; Rats, Sprague-Dawley ; Sciatic Nerve ; Tibial Nerve ; Transplants

BACKGROUND: Methcobalamin was known to act as a methyl donor in DNA metabolism and increase Protein synthesis for nerve regeneration. To determine whether methylcobalamin affects capsaicin induced polyneuropathy in rat sural nerves. METHODS: On their second day of life, 18 newborn rats were injected subcutaneously with capsaicin(50mg/kg). Ten rats were treated with methylcobalamin(500microgram/kg) and eight rats with normal saline 5 days a week for 12weeks after capsaicin injection. Using morphometry and computer digitization, the number and sloe distribution of myelinated and unmyelinated fibers were evaluated in sural nerves at 13 weeks. RESULTS: There was significant difference in the number of unmyelinated fibers between two groups(control group 33,321 +/- 15,539/mm2; methylcobalamin group 99,614+/-20,581/mm2. p<0.0001). Methylcobalamin did not change the number and size distribution of'myelinated fibers. The size distribution of'unmyelinated fibers was approximately the same. CONCLUSIONS: This study suggested that methylcobalamln could increase regeneration of peripheral nerve morphometrically. It appears that methylcobalamin might be one of the useful therapeutic agents in various polyneuropathies.
Animals ; Capsaicin* ; DNA ; Humans ; Infant, Newborn ; Metabolism ; Myelin Sheath ; Nerve Regeneration ; Peripheral Nerves* ; Polyneuropathies ; Rats* ; Regeneration ; Sural Nerve ; Tissue Donors

BACKGROUND: Pulsed radiofrequency (PRF) may be used in the treatment of patients with some pain syndromes that cannot be controlled by alternative techniques. The objective of the present study is to examine the ultrastructural changes in rat sciatic nerve after PRF, using synchrotron small angle X-ray scattering (SAXS). METHODS: Twenty rats (Male Sprague-Dawley, about 250 grams) were used this study. The PRF is applied to the afferent axons of the sciatic nerves of the rats in ex vivo state, and the ultrastructure of axons were studied after 1 (N = 5), 4 (N = 5), and 6 (N = 5) weeks by SAXS. The control (N = 5) consisted of non-treated sciatic nerve to provide a statistical differential comparison. RESULTS: In the PRF group, the periodic peaks of myelin sheath and collagen fibrils were not changed compared to the control group, in the time progression of 1, 4, and 6 weeks. But the periodic peaks of interfibrillar distance of collagen were greater at 1 and 4 weeks after PRF, comparing to the control group, but it had tendency to return to normal in 6 weeks. CONCLUSIONS: It is suggested that PRF did not induce ultrastructural change of myelin sheath and collagen fiber, but it induced the change of distance between collagen fibrils of the nerve tissue. This change was not caused by thermal injury but by electromagnetic fields and it is reversible.
Animals ; Axons ; Collagen ; Electromagnetic Fields ; Humans ; Myelin Sheath ; Nerve Tissue ; Rats* ; Rats, Sprague-Dawley ; Sciatic Nerve* ; Synchrotrons

When a large peripheral nerve defect occurs, an autologous nerve graft is the most ideal method of recinstruction. But an autologous nerve graft has many limitations due to donor site morbidities. Many previous focused on finding the ideal nerve conduit. Among them, Gore-Tex(R) has several advantages over other conduits. It can be manipulated to a suitable size, does not collapse easily, and it is a semi- permeable material that contain pores. A round shaped nerve can be newly formed because of its smooth inner surface. The purpose of this study was to evaluate the availability of Gore-Tex(R) tube as a nerve conduit at the peripheral nerve defect in the rat sciatic nerve. The 10 mm nerve gap was made in each group. A Gore-Tex(R) tube filled with skeletal muscle was inserted and autologous nerve graft was harvested, respectively. In the experimental group, we placed a 0.5mm thickness, 30micrometer pored, 1.8mm in diameter and 14mm length tube with skeletal muscle inserted inside. In the control group, the nerve gap was inserted with a rat sciatic nerve. We estimated the results electrophysiologically and histologically to 16 weeks postoperatively. Results in the nerve conduction velocity, total myelinated axon count, myelin sheath thickness and mean nerve fiber diameter, the experimental group was substantially lower than that of the control group, but the statistic difference was not significant (p<0.05). The morphology was very similar in both groups, microscopically. From the above results, We conclude that Gore-Tex(R) qualifies as an ideal nerve conduit. It is suggested that Gore-Tex(R) tube filled with skeletal muscle may, substitute for an autologous nerve graft.
Animals ; Axons ; Humans ; Muscle, Skeletal ; Myelin Sheath ; Nerve Fibers ; Neural Conduction ; Peripheral Nerves* ; Rats ; Sciatic Nerve ; Tissue Donors ; Transplants

PURPOSE: To determine the upper limit of peripheral nerve lengthening without loss of function, the recovery time of peripheral nerve palsy due to nerve lengthening and their histological changes. MATERIALS AND METHODS: Twelve adult New Zealand rabbits weighing about 2.5 kg were assigned to the following groups. Group 1 (n=6) was subjected to slow tissue expansion with 30% of nerve lengthening while group 2 (n=6) was rapid expansion with 40% lengthening of nerve. The expanders were refilled every 2 times during the 2nd and 4th weeks making a total four times of expansion. The rabbits were assessed in terms of affected leg paralysis, neural length gain, EMG with nerve conduction velocity and histological changes. RESULTS: In group 1 (n=6), paralysis on affected leg was found in one rabbit and was recovered spontaneously on the 4th weeks after expander removal. In Group 2 (n=6), paralysis was found in four rabbits, and three of them were recovered on 4, 5 and 9 weeks after removal of the expander. EMG study showed increase in distal latency of 2.50+/- 0.20 m/sec, and decrease in nerve conduction velocity of 62.49+/- 5.30 m/sec compared to normal side with 1.89+/- 0.14 m/sec and 75.39+/- 7.82 m/sec. The mean neural length gain was 6 mm (30% of 20 mm of initial pre-experimental nerve length) in group 1 and 8 mm (40% of 20 mm) in group 2. Light microscopic examination revealed the loss of segmental myelination, decrease of myelination, and vacuolation. Electron microscopic examination showed that the normal ring shaped contour of axon was changed to convoluted shape.
Adult ; Axons ; Humans ; Leg ; Myelin Sheath ; Nerve Expansion ; Neural Conduction ; Paralysis ; Peripheral Nerves ; Rabbits ; Sciatic Nerve* ; Tissue Expansion*

The purpose of this study was to compare clinical availability of fibrin adhesive technique with microneural suture technique. We applicated fibrin adhesive technique and microneural suture technique on cut sciatic nerve in rat and used to Compound muscle action potential of rat thigh muscle compartment and histologic finding for comparision of clinical availability. The results were as following. 1. Using latency and amplitude in Compound muscle action potential test, we compared microneural suture technique with fibrin adhesive technique for nerve regeneration effect. the means was slightly different between two method. but there's no statistically significant differences. 2. Histologic finding was similar in microneural suture technique and fibrin adhesive technique for regeneration of axon and myelin sheath in destruction site after nerve anastomosis. These results showed that the efficacy of fibrin adhesive technique was similar to that of conventional microneural suture technique. Moreover, fibrin adhesive technique is decreased operating time and imporved of incapability of accessment in conventional suture technique. Therefore this technique is a useful method to nerve anastomosis in nerve enervation and neurotransplantation.
Action Potentials* ; Animals ; Axons ; Fibrin Tissue Adhesive* ; Fibrin* ; Myelin Sheath ; Nerve Regeneration ; Rats* ; Regeneration* ; Sciatic Nerve* ; Suture Techniques* ; Sutures* ; Thigh

Many anatomists and clinicians who investigate the peripheral nerve concern about the composition of the spinal roots of each terminal nerve of the brachial plexus. From this viewpoint, the spinal root composition of the ulnar nerve is still unclear. Several anatomy textbooks describe that the ulnar nerve is composed of the ventral rami of the C8, T1 and often C7. There is no literature regarding the frequency and contribution quantity of C7 to the ulnar nerve. The purpose of present study was to determine frequency and contribution quantity of the C7 to the ulnar nerve. Fifty cadavers of brachial plexus were obtained from cadavers of Korean adults. The brachial plexus containing the ulnar nerve were extracted from the axilla and the extracted samples were immersed in Guanidine-HCl (0.2 M) for 2 weeks to soften the connective tissue around the nerve bundles. C7 was contributed to the ulnar nerve in all sides (100%). The numbers of the myelinated axons of C7 participating to the ulnar nerve was 1,452+/-429 (mean+/-S.D.). Thus the C7 can be considered as always participating component of the ulnar nerve, not often participation, although numbers of the myelinated axons of C7 was lesser than those of the C8, but similar to those of the T1. The results of the study provide a reference for accurate diagnosis and treatment regarding ulnar nerve injury due to various accidents.
Adult ; Anatomists ; Axilla ; Axons ; Brachial Plexus ; Cadaver ; Connective Tissue ; Humans ; Myelin Sheath ; Peripheral Nerves ; Spinal Nerve Roots ; Ulnar Nerve