Yuhui Kou

Lumbricus extract promotes the regeneration of injured peripheral nerve in rats

BACKGROUND Earthworms regenerate amputated parts of their body if the nervous system is intact. Lumbricus is one traditional Chinese medicine (TCM), which has been used in China to promote nerve function for hundreds of years. AIM OF THE STUDY To investigate the beneficial effect of lumbricus extract on peripheral nerve regeneration in rats. MATERIALS AND METHODS Nerve function was surgically impaired in Sprague-Dawley (SD) rats by clamping of the left sciatic nerve. The sham-operated group (surgery but no sciatic nerve clamping), control group, and treatment group were treated with 2 ml 0.9% NaCl, 0.9% NaCl, and lumbricus extract (1g/ml), respectively. Treatments were administered once daily after the operation for 6 weeks. During this period, motor function was monitored by walking track analysis, conduction function of injured sciatic nerve was monitored by electrophysiology, and regeneration of myelinated nerve was assessed by immunohistochemistry. RESULTS (1) For nerve function index value, treatment group is higher than control group. (2) For conduction velocity of injured sciatic nerve, treatment group is higher than control group at week 3 and 6. (3) For the number of regenerated myelinated nerve fibers, treatment group is higher than control group at week 2 and 6. CONCLUSIONS Lumbricus extract appears to enhance sciatic nerve regeneration and function recovery following injury, suggesting the clinical potential of lumbricus extract on the treatment of peripheral nerve injury in humans.

Electrical Stimulation Promotes Regeneration of Defective Peripheral Nerves after Delayed Repair Intervals Lasting under One Month

Background Electrical stimulation (ES) has been proven to be an effective means of enhancing the speed and accuracy of nerve regeneration. However, these results were recorded when the procedure was performed almost immediately after nerve injury. In clinical settings, most patients cannot be treated immediately. Some patients with serious trauma or contaminated wounds need to wait for nerve repair surgery. Delays in nerve repair have been shown to be associated with poorer results than immediate surgery. It is not clear whether electrical stimulation still has any effect on nerve regeneration after enough time has elapsed. Methods A delayed nerve repair model in which the rats received delayed nerve repair after 1 day, 1 week, 1 month, and 2 months was designed. At each point in time, the nerve stumps of half the rats were bridged with an absorbable conduit and the rats were given 1 h of weak electrical stimulation. The other half was not treated. In order to analyze the morphological and molecular differences among these groups, 6 ES rats and 6 sham ES rats per point in time were killed 5 days after surgery. The other rats in each group were allowed to recover for 6 weeks before the final functional test and tissue observation. Results The amounts of myelinated fibers in the distal nerve stumps decreased as the delay in repair increased for both ES rats and sham ES rats. In the 1-day-delay and 1-week-delay groups, there were more fibers in ES rats than in sham ES rats. And the compound muscle action potential (CMAP) and motor nerve conduction velocity (MNCV) results were better for ES rats in these two groups. In order to analyze the mechanisms underlying these differences, Masson staining was performed on the distal nerves and quantitative PCR on the spinal cords. Results showed that, after delays in repair of 1 month and 2 months, there was more collagen tissue hyperplasia in the distal nerve in all rats. The brain-derived neurotrophic factor (BDNF) and trkB expression levels in the spinal cords of ES rats were higher than in sham ES rats. However, these differences decreased as the delay in repair increased. Conclusions Electrical stimulation does not continue to promote nerve regeneration after long delays in nerve repair. The effective interval for nerve regeneration after delayed repair was found to be less than 1 month. The mechanism seemed to be related to the expression of nerve growth factors and regeneration environment in the distal nerves.

Biodegradable Conduit Small Gap Tubulization for Peripheral Nerve Mutilation: A Substitute for Traditional Epineurial Neurorrhaphy

Nerve regeneration and re-innervation are usually difficult after peripheral nerve injury. Epineurium neurorrhaphy to recover the nerve continuity is the traditional choice of peripheral nerve mutilation without nerve defects, whereas the functional recovery remains quite unsatisfactory. Based on previous research in SD rats and Rhesus Monkeys, a multiple centers clinical trial about biodegradable conduit small gap tubulization for peripheral nerve mutilation to substitute traditional epineurial neurorrhaphy was carried out. Herein, the authors reviewed the literature that focused on peripheral nerve injury and possible clinical application, and confirmed the clinical possibilities of biodegradable conduit small gap tubulization to substitute traditional epineurial neurorrhaphy for peripheral nerve mutilation. The biodegradable conduit small gap tubulization to substitute traditional epineurial neurorrhaphy for peripheral nerve mutilation may be a revolutionary innovation in peripheral nerve injury and repair field.

The Histological Analysis of Biological Conduit Sleeve Bridging Rhesus Monkey Median Nerve Injury with Small Gap

Based on the research on small gap bridging peripheral nerve injury in SD rats, we decided to investigate the histological analysis possibility of bridging peripheral nerve injury with small gap using a de-acetyl chitin conduit in primate. Median nerves of 8 rhesus monkeys were cut at 2 cm above the elbow, and the right sides were subjected to small gap (2 mm) bridging to repair the nerve with chitin conduit (conduit inner diameter 4 mm; length 10 mm); the left sides were subjected to traditionary epineurium suture. Histology detections were conducted after 6th month. The conduit was almost absorbed and the conduit cast contour disappeared after 6 months. The histological analysis displayed that the regenerated nerve fibers in conduit grew forward in fasciculation. The re-myelinated nerve axons number per unit area in the conduit group distal segment was higher than that of traditionary epineurium suture group. The biocompatibility of biological chitin conduit in primate rhesus monkeys was quite good. The regenerated nerve fibers in conduit grew forward in fasciculation. The histological analysis results of biological conduit in primate rhesus monkeys were better than the traditionary epineurium suture. The biological conduit can be used in primate rhesus monkeys to substitute the traditionary epineurium suture methods.

The Electrophysiology Analysis of Biological Conduit Sleeve Bridging Rhesus Monkey Median Nerve Injury with Small Gap

Based on the research on small gap bridging peripheral nerve injury in SD rats, we propose to investigate the possibility of bridging peripheral nerve injury with small gap using a de-acetyl chitin conduit in primates. The median nerves of 8 rhesus monkeys were cut at 2 cm above the elbow; the right sides were subjected to small gap (2 mm) bridging to repair the nerve with chitin conduit (conduit inner diameter 4 mm; length 10 mm); the left sides were subjected to traditionary epineurium suture. The electrophysiology analysis was conducted after the 3rd month and 6th month, respectively. The adhesions condition of biological conduit was only a little after the 15 3rd month; the conduit can remain cast contour; vessels can be seen on the conduit 16 surface and nerve intumescentia was not obvious. The adhesion and intumescentia condition can display better biocompatibilities than traditional suture methods. The motor nerve conduction velocity was only 1/2 of the control group. Although the motor nerve conduction velocity of the conduit group was a little higher than the epineurium suture group, there was no statistically significant difference (P>0.05) at the 3rd month (). The conduit cast contour disappeared after 6 months. The motor nerve conduction velocity was only 4/5 of the control group. The motor nerve conduction velocity of the conduit group was higher than the epineurium suture group; there were statistically significant differences (P<0.05) at 6 months. The nerve trunk conduction velocity of biological conduit was higher than the epineurium suture group at the 6th month, and there were statistically significant differences (P<0.05) (). The biocompatibility of the biological chitin conduit in primate rhesus monkeys was quite good. The electrophysiological results of biological conduit in primate rhesus monkeys were better than the traditional epineurium suture. The biological conduit can be used in primate rhesus monkeys to substitute for the traditional epineurium suture methods.

The Experimental Study of Absorbable Chitin Conduit for Bridging Peripheral Nerve Defect with Nerve Fasciculu in Rats

To investigate the possibility of constructing artificial peripheral nerves using de-acetyl chitin conduit, the sciatic nerves defect model was built at left legs in SD rats. They were divided into 3 groups randomly: group A: nerve graft in situ (n = 12, gap distance 10 mm); group B: biological chitin conduit bridging the peripheral nerve defect (n = 12, gap distance 10 mm); group C: biological chitin conduit bridging the peripheral nerve defect with nerve fibers in conduits (n = 12, gap distance 10 mm). Electrophysiological examination, histological examination and re-myelinated axons counting were applied after 6th and 12th week after operation, respectively. Regenerated nerve fibers were seen in the distal nerve segments of all three groups. The nerve conduction velocity and the re-myelinated axons counting of group A were better than that of group C at both 6th and 12th week time points (p < 0.05). The nerve conduction velocity and the re-myelinated axons counting of group C were better than that of group B at both 6th and 12th week time points (p < 0.05). The repair effects of chitin conduit with nerve fibers in conduit bridging peripheral nerve defect (10 mm) were better than that of simple conduit bridging group, and that of group A (nerve graft group) was better than that of group C.

Epimedium Extract Promotes Peripheral Nerve Regeneration in Rats

Effects of Epimedium extract and its constituent icariin on peripheral nerve repair were investigated in a crush injury rat model. Animals were divided into four groups: sham, control, Epimedium extract, and icariin groups. At postoperative weeks 1, 2, 4, and 8, nerve regeneration and functional recovery were evaluated by sciatic functional index (SFI), nerve electrophysiology, nerve pinch test, and muscle wet weight. Results showed that at 2 and 4 weeks after surgery rats in the Epimedium group displayed a better recovery of nerve function than that in the icariin and control groups, with better recovery in the icariin group than in the control group. The nerve pinch test showed that nerve regeneration was greater in the Epimedium group and the icariin group as compared to the control group. In addition, the muscle wet weight in the Epimedium group was significantly improved when compared with the icariin group, and the improvement in the icariin group was better than that in the control group at 8 weeks after operation. Our findings suggest that Epimedium extract effectively promotes peripheral nerve regeneration and improves the function of damaged nerves.

Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive for S100 (Schwann cell marker) and glial fibrillary acidic protein (glial cell marker) at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvironment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

The Experimental Research of Nerve Fibers Compensation Amplification Innervation of Ular Nerve and Musculocutaneous Nerve in Rhesus Monkeys

Abstract This experiment intended to authenticate the compensation and amplification effect of regenerated nerve fibers after nerve injury in primate. The Rhesus Monkeys right ulnar nerves and musculocutaneous nerves were chosed. The proximal impaired ulnar nerve as the proximal end and the distal impaired ulnar nerve musculocutaneous nerve as the distal ends. The ulnar nerve proximal stump fibers can grow into both the ulnar nerve distal stump and the musculocutaneus nerve at the same time and established two different electrophysiological conduction passageway. There exist nerve fibers compensation amplification effect after peripheral nerve injury on Rhesus Monkeys.

The observation of phenotypic changes of Schwann cells after rat sciatic nerve injury.

Abstract: To describe the phenotypic changes of Schwann cells during nerve regeneration, we made two different neurorrhaphy models after rat sciatic nerves injury, the epineurium neurorrhaphy and small gap bridging suture. Then, at selected time points after surgery (1d, 3d, 5d, 7d, 2 weeks, 3weeks), the materials were drawn for detecting the expression of GFAP, Sox2, Krox20 by immunofluorescence. GFAP is expressed in non-myelin-forming Schwann cells and Krox20 is a marker for myelin-forming cells in the adult nerve. Sox2 is a marker for neural stem and progenitor cells. Our findings showed the rule of phenotypic changes of Schwann cells during nerve regeneration. Furthermore, the difference in the phenotypic changes of Schwann cells between two operation methods indicated that the small gap changes the regenerated microenvironment and may be one of the reasons that small gap bridging suture is superior to the epineurium suture.