Peripheral nerve injury (PNI) is a common neurological dysfunction. In clinical practice, autologous nerve transplantation is used to solve problems related to PNI, such as limited donor resources, neuroma formation and high donor incidence rate. Therefore, searching for new nerve regeneration materials has become a hot research topic. The decellularized extracellular matrix (dECM) hydrogel provides a scaffold for nerve regeneration by removing the cellular components in biological tissues, preserving the extracellular matrix, and is a potential therapeutic material for nerve regeneration. This article reviews the research progress of dECM hydrogel for PNI and looks forward to the clinical prospects of this research direction.
ObjectiveTo construct recombinant adenovirus expressing nerve growth factor (NGF) and myelin associated glycoprotein (MAG) (Ad-NGF-MAG) and to investigate its effect on repair and regeneration of sciatic nerve injury in rats. MethodsNGF and MAG gene sequences were cloned into shuttle plasmid pCA13 of adenovirus type 5. After packed in HEK293 cells, the recombinant Ad-NGF-MAG underwent sequence and identification. Thirty-two male Sprague Dawley rats were randomly divided into 4 groups (n=8): control group (normal control), adenovirus vector group (Ad group), Ad-NGF group, and Ad-NGF-MAG group. The sciatic nerve injury model was established by transection of the right sciatic nerve; then, the empty adenovirus vector, Ad-NGF, and Ad-NGF-MAG were injected into the gastrocnemius muscle of the affected limb at a dose of 1×108 PFU every other day for 3 times in Ad group, AdNGF group, and Ad-NGF-MAG group, respectively. The right sciatic nerve was exposed only, and then the incision was closed in the control group. The sciatic nerve function index (SFI) was measured, and neuro-electrophysiology was observed; mRNA and protein expressions of NGF and MAG were detected by RT-PCR and Western blot; and histological examination was performed at 31 days after operation. ResultsRecombinant adenovirus vectors of Ad-NGF and Ad-NGF-MAG were constructed successfully. All rats survived and incision healed by first intension. The SFI, nerve conduction velocity, evoked potential amplitude, and latent period of Ad-NGF-MAG group were significantly better than those of Ad group and Ad-NGF group (P < 0.05). MAG mRNA and protein expressions of Ad-NGF-MAG group were the highest in all the groups (P < 0.05). The expressions of NGF mRNA and protein increased in Ad-NGF group and AdNGF-MAG group when compared with control group and Ad group (P < 0.05). Histological examination showed that the nerve had good continuity in control group; nerve fibers disarranged in Ad group; neurons connections formed in some nerve fibers of Ad-NGF group, but nerve fibers arrange disorderly; and the growth of the nerve were ordered and wellstructured in Ad-NGF-MAG group. ConclusionAd-NGF-MAG can effectively promote the growth of the nerve and inhibit the form of abnormal branches, facilitating the repair of sciatic nerve injury in rats.
Objective To investigate the neuroprotective effect of conducting hydrogel loaded with tetramethylpyrazine sustained-release microparticles (hereinafter referred to as “TGTP hydrogel”) on spinal cord injury rats. Methods Forty-eight adult female Sprague Dawley rats were randomly divided into 4 groups: sham operation group (group A), model group (group B), conductive hydrogel group (group C), and TGTP hydrogel group (group D), with 12 rats in each group. Only laminectomy was performed in group A, and complete spinal cord transection was performed in groups B, C, and D. Basso-Bettie-Bresnahan (BBB) score was used to evaluate the recovery of hind limb motor function of each group before modeling and at 1, 3, 7, 14, and 28 days after modeling, respectively. At 28 days after modeling, the rats were sacrificed for luxol fast blue (LFB) staining to detect myelin regeneration. Nissl staining was used to detect the survival of neurons. Immunohistochemical staining was used to evaluate the expression of inflammation-related factors [nuclear factor кB (NF-кB), tumor necrosis factor α (TNF-α), and interleukin 10 (IL-10)]. Immunofluorescence staining and Western blot were used to evaluate the expression of neurofilament 200 (NF200). RseultsBBB scores of group A were significantly better than those of the other three groups at all time points after modeling (P<0.05); at 14 and 28 days after modeling, there was no significant difference in BBB scores between groups C and D (P>0.05), but the BBB score of group D was significantly better than that of group B (P<0.05). LFB staining and Nissl staining showed that the structure of neurons and myelin in group A was intact, and the myelin integrity and survival number of neurons in group D were significantly better than those in groups B and C. Immunohistochemical staining showed that the absorbency (A) value of NF-кB and TNF-α in group A were significantly lower than those in groups B and C (P<0.05), the A value of IL-10 was significantly higher than that in the other three groups (P<0.05); the A value of NF-κB in group D was significantly lower than that in groups B and C, the A value of TNF-α in group D was significantly lower than that in group B, while the A value of IL-10 in group D was significantly higher than that in group B (P<0.05). Immunofluorescence staining showed that the structure of neurons and nerve fibers in group A was clear and the fluorescence intensity was high. The fluorescence intensity of NF200 in group D was higher than that in groups B and C, and some nerve fibers could be seen. Western blot analysis showed that the relative expression of NF200 in group A was the highest, and the relative expression of NF200 in group D was significantly higher than that in groups B and C (P<0.05). Conclusion The TGTP hydrogel can effectively promote the recovery of motor function in rats with spinal cord injury, and its mechanism may be related to the regulation of inflammatory response.
Objective To obtain highly purified and large amount of Schwann cells (SCs) by improved primary culture method, to investigate the biocompatibility of small intestinal submucosa (SIS) and SCs, and to make SIS load nerve growth factor (NGF) through co-culture with SCs. Methods Sciatic nerves were isolated from 2-3 days old Sprague Dawley rats and digested with collagenase II and trypsin. SCs were purified by differential adhesion method for 20 minutes and treated with G418 for 48 hours. Then the fibroblasts were further removed by reducing fetal bovine serum to 2.5% in H-DMEM. MTT assay was used to test the proliferation of SCs and the growth curve of SCs was drawn. The purity of SCs was calculated by immunofluorescence staining for S-100. SIS and SCs at passage 3 were co-cultured in vitro. And then the adhesion, proliferation, and differentiation of SCs were investigated by optical microscope and scanning electron microscope (SEM). The NGF content by SCs was also evaluated at 1, 2, 3, 4, 5, and 7 days by ELISA. SCs were removed from SIS by repeated freeze thawing after 3, 5, 7, 10, 13, and 15 days of co-culture. The NGF content in modified SIS was tested by ELISA. Results The purity of SCs was more than 98%. MTT assay showed that the SCs entered the logarithmic growth phase on the 3rd day, and reached the plateau phase on the 7th day. SCs well adhered to the surface of SIS by HE staining and SEM; SCs were fusiform in shape with obvious prominence and the protein granules secreted on cellular surface were also observed. Furthermore, ELISA measurement revealed that, co-culture with SIS, SCs secreted NGF prosperously without significant difference when compared with the control group (P gt; 0.05). The NGF content increased with increasing time. The concentration of NGF released from SIS which were cultured with SCs for 10 days was (414.29 ± 20.87) pg/cm2, while in simple SIS was (4.92 ± 2.06) pg/cm2, showing significant difference (P lt; 0.05). Conclusion A large number of highly purified SCs can be obtained by digestion with collagenase II and trypsin in combination with 20-minute differential adhesion and selection by G418. SIS possesses good biocompatibility with SCs, providing the basis for further study in vivo to fabricate the artificial nerve conduit.
Objective To analyze the therapeutic effect of olfactory ensheathing cells (OECs) transplantation for central nervous system diseases. Methods Between November 2001 and January 2008, 1 255 participants with central nervous system diseases were enrolled in this cl inical study for fetal OECs transplantation. There were 928 males and 327 femalesaged 1.2-87 (mean 40) years. The course of disease was (4.52 ± 4.67) years. Among them, 656 participants suffered from chronic spinal cord injury (SCI), 457 amyotrophic lateral sclerosis (ALS), 68 cerebral palsy (CP), 20 multiple sclerosis (MS), 11 the sequelae of stoke, 10 ataxia, and 33 residual diseases. The participants came from 71 countries or regions. Accidentally abortional fetal olfactory bulbs were donated voluntarily and were cultured for 2 weeks, then were transplanted. Results One thousand one hundred and twenty-eight cases were followed up for 2-8 weeks (mean 4 weeks) to obtain integrated data. Among them, the neurological functional amel ioration was noticed in 994 participants with the overall short-term improvement rate of 88.12%. Seventy-six patients experienced the various perioperative compl ications with the incidence rate of 6.74%. One hundred and twenty patients with SCI received over 1 year follow-up. And according to ASIA assessment, motor scores increased from (39.82 ± 20.25) to (44.55 ± 18.99) points, l ight touch scores from (51.56 ± 25.89) to (59.81 ± 27.72) points, pain scores from (50.36 ± 27.44) to (57.09 ± 28.51) points for foreign patients (P lt; 0.05); motor scores increased from (40.52 ± 20.80) to (46.45 ± 20.35) points, l ight touch scores from (55.64 ± 26.32) to (68.64 ± 25.89) points, pain scores from (57.05 ± 26.00) to (66.13 ± 24.29) points for good rehabil itation Chinese patients (overall P lt; 0.05); motor scores from (37.03 ± 18.52) to (38.03 ± 18.50 points (P lt;0.05), l ight touch scores from (45.88 ± 22.56) to (46.63 ± 23.09) points (P gt; 0.05), pain scores from (45.25 ± 23.68) to (45.28 ± 23.63) points (P gt; 0.05) for poor rehabil itation Chinese patients. Compared foreign patients and good rehabil itation Chinese patients with poor rehabil itation Chinese patients, difference in score change was remarkable (P lt; 0.05). One hundred and six cases of ALS, 32 CP, 8 MS, 7 ataxia, and 2 stroke sequelae were followed up for 3-48, 3-36, 2-20, 7-17, 6 and 24 months, One hundred and six cases of respectively. Majority of them (113/155, 72.9%）were benefited from OECs transplantation. Conclusion OECs transplantation into brain and spinal cord is feasible and safe . The therapeutic strategy is valuable treatment for such central nervous system diseases such as chronic SCI, ALS, CP and stroke sequelae and can improve the patients’ neurological functions and/or decrease the progressive deterioration.
Objective To investigate the effects of 3 methods (suture removal, suture removal with epineurium neurolysis, and l igated femoral nerve resection with end-end suture) in repairing femoral nerve injury after l igation in different periods so as to provide a reference for cl inical use of repairing iatrogenic l igation injury of the peri pheral nerve. Methods A total of 120 adult female Sprague Dawley rats, weighing (200 ± 20) g, were used to prepare the animal models of left femoralnerve l igation, and were divided into groups A (n=40), B (n=40), and C (n=40) according different repairing methods. Atimmediate, 1, 3, and 5 months (10 rats each time point) after l igation, suture removal was performed in group A, suture removal with epineurium neurolysis in group B, and l igated femoral nerve resection with end-end suture in group C. At 3 months after operation, the foot-base angle (FBA) and the heels-tail angle (HTA), action potential and conduction velocity of femoral nerve, and wet weight of quadriceps femoris muscle (QFM) were measured; the samples of quadriceps femoris and femoral nerve were harvested for histological observation, muscle fiber count, and nerve fiber passing rate measuring. Results The FBA in group A was significant smaller than that in group C at immediate, 1, 3, and 5 months (P lt; 0.05), but there was no significant difference between groups A and B (P gt; 0.05). The HTA in group A was significantly smaller than that in group C at immediate, 1, 3, and 5 months (P lt; 0.05), and the THA in group B was significantly smaller than that in group C at 1, 3, and 5 months (P lt; 0.05). The wet weight of QFM in group B was significantly higher than that in group C at immediate, 3, and 5 months (P lt; 0.05), and the wet weight of QFM in group A was significantly higher than that in group C at immediate and 3 months (P lt; 0.05), but no significant difference was found between groups A and B at immediate, 1, and 3 months (P gt; 0.05). There was significant difference in the action potential of femoral nerve between group A and groups B and C at immediate and 1 month (P lt; 0.05), but there was no significant difference between other groups at 3 and 5 months (P gt; 0.05) except between groups A and C at 5 months (P lt; 0.05). The conduction velocity of femoral nerve in group A was significantly faster than that in group C at immediate, 1, and 5 months (P lt; 0.05), and it was significantly faster in group A than in group B at immediate and 1 month (P lt; 0.05), but no significant difference was found between groups A and B at 3 and 5 months (P gt; 0.05), between groups B and C at other time points (P gt; 0.05) except at immediate (P lt; 0.05). The count of muscle fibre of the quadriceps femoris was significantly more in groups A and B than in group C at immediate (P lt; 0.05); it was significantly more in group A than in group B at 5 months (P lt; 0.05). The passing rate of the femoral nerve fiber was significantly higher in group A than in groups B and C at 3 months (P lt; 0.05), but no significant difference was found between the other groups (P gt; 0.05). Conclusion After femoral nerve l igation, suture removal method has the best effect at early term, the next is epineurium neurolysis method, and the worst is the l igation femoral nerve resection with end-end suture repair.
Objective To elucidate the new concept and theory of neurorestoratology. Methods With the review of the development course and important research works in the field of neurorestoratology during the 20th century, especially recent 30 years, the regularity summary, science and technology philosophy induction, and theory distillation were carried out in this article. Results The new discipl ine system was brought forward as follows: ① Definition: neurorestoratology was asub-discipl ine of neuroscience which studies neural regeneration, neural structural repair of replacement, eruroplasticity and neuromodulation. The core purpose was to promote neural functional recovery of all neural degenerative diseases and damages. ② One central task and two basic points: to recover neurological function was the central research task all the time and the two basic points were the precl inical (basic) neurorestoration and the cl inical neurorestoration. ③ Four rationale of the discipl ine: l imited renovation, relearning, insufficient reserve, and l ifelong reinforcement. ④ Five major factors of neurorestoratology (5N’s dogma): neuroregeneration, neurorepair, neuroplasticity, neuromodulation, neurorehabil itation. “Neuroprotection” appeared to be included in the broad definition. ⑤ Four-step rule of neurorestoratology: structural neurorestoration, signal neurorestoration, rehabil itative neurorestoration, and functional neurorestoration. ⑥ Emphasize that translational medicine from lab to bed in neurorestoration. Conclusion The discipl ine of neurorestoratology has the vast development prospectand will be sure to increase the rapid progress of the basic and cl inical restorative neuroscience.
ObjectiveTo investigate the early effects of acellular xenogeneic nerve combined with adipose-derived stem cells (ADSCs) and platelet rich plasma (PRP) in repairing facial nerve injury in rabbits.MethodsThe bilateral sciatic nerves of 15 3-month-old male Sprague-Dawley rats were harvested and decellularized as xenografts. The allogeneic ADSCs were extracted from the neck and back fat pad of healthy adult New Zealand rabbits with a method of digestion by collagenase type Ⅰ and the autologous PRP was prepared by two step centrifugation. The 3rd generation ADSCs with good growth were labelled with CM-Dil living cell stain, and the labelling and fluorescence attenuation of the cells were observed by fluorescence microscope. Another 32 New Zealand rabbits were randomly divided into 4 groups and established the left facial nerve defect in length of 1 cm (n=8). The nerve defects of groups A, B, C, and D were repaired with CM-Dil-ADSCs composite xenogeneic nerve+autologous PRP, CM-Dil-ADSCs composite xenogeneic nerve, xenogeneic nerve, and autologous nerve, respectively. At 1 and 8 weeks after operation, the angle between the upper lip and the median line of the face (angle θ) was measured. At 4 and 8 weeks after operation, the nerve conduction velocity was recorded by electrophysiological examination. At 8 weeks after operation, the CM-Dil-ADSCs at the distal and proximal ends of regenerative nerve graft segment in groups A and B were observed by fluorescence microscopy; after toluidine blue staining, the number of myelinated nerve fibers in regenerated nerve was calculated; the structure of regenerated nerve fibers was observed by transmission electron microscope.ResultsADSCs labelled by CM-Dil showed that the labelling rate of cells was more than 90% under fluorescence microscope, and the labelled cells proliferated well, and the fluorescence attenuated slightly after passage. All the animals survived after operation, the incision healed well and no infection occurred. At 1 week after operation, all the animals in each group had different degrees of dysfunction. The angle θ of the left side in groups A, B, C, and D were (53.4±2.5), (54.0±2.6), (53.7±2.4), and (53.0±2.1)°, respectively; showing significant differences when compared with the healthy sides (P<0.05). At 8 weeks after operation, the angle θ of the left side in groups A, B, C, and D were (61.9±4.7), (56.8±4.2), (54.6±3.8), and (63.8±5.8)°, respectively; showing significant differences when compared with the healthy sides and with the values at 1 week (P<0.05). Gross observation showed that the integrity and continuity of regenerated nerve in 4 groups were good, and no neuroma and obvious enlargement was found. At 4 and 8 weeks after operation, the electrophysiological examination results showed that the nerve conduction velocity was significantly faster in groups A and D than in groups B and C (P<0.05), and in group B than in group C (P<0.05); no significant difference was found between groups A and D (P>0.05). At 8 weeks after operation, the fluorescence microscopy observation showed a large number of CM-Dil-ADSCs passing through the distal and proximal transplants in group A, and relatively few cells passing in group B. Toluidine blue staining showed that the density of myelinated nerve fibers in groups A and D were significantly higher than those in groups B and C (P<0.05), and in group B than in group C (P<0.05); no significant difference was found between groups A and D (P>0.05). Transmission electron microscope observation showed that the myelinated nerve sheath in group D was large in diameter and thickness in wall. The morphology of myelin sheath in group A was irregular and smaller than that in group D, and there was no significant difference between groups B and C.ConclusionADSCs can survive as a seed cell in vivo, and can be differentiated into Schwann-like cells under PRP induction. It can achieve better results when combined with acellular xenogeneic nerve to repair peripheral nerve injury in rabbits.
OBJECTIVE In order to investigate the opportunity of repair and prognosis of recurrent laryngeal nerve injuries after thyroidectomy. METHODS Twelve cases with recurrent laryngeal nerve injuries after thyroidectomy were immediately and delayed operated on nerve repair and reinnervation. In immediate operation, 5 cases were repaired by direct recurrent laryngeal nerve suture, and 1 case was treated by transposition of the phrenic nerve to the recurrent laryngeal nerve and sutured the adductor branch to the branch of ansa cervicalis. In delayed operation, 3 cases were treated by anastomosis the main trunk of ansa cervicalis to the adductor branch of recurrent laryngeal nerve, and 3 cases were operated on neuromuscular pedicle to reinnervate posterior cricoarytenoid muscle. RESULTS Followed up 6 months, the effect was excellent in 1 case who was immediately operated by selective reinnervation of the abductor and adductor muscles of the larynx, better in 9 cases, and poor in 2 cases who were delayed operated over 12 months. CONCLUSION It can be concluded that the earlier reinnervation is performed, the better prognosis is.
ObjectiveThe aim of this study was to evaluate the repair effect of spontaneous reinnervation in rats underwent recurrent laryngeal nerve (RLN) transection. MethodsThirty male Wistar rats (340-360 g) were divided into experiment group (n=15) and blank control group (n=15), and then 15 rats of these 2 groups were divided into 3 time point groups equally:4 weeks group, 8 weeks group, and 12 weeks group. Fifteen rats of experiment group underwent right RLN transection with excision of a 5 mm segment, and other 15 rats of blank control group exposed RLN only, without transection. Grade of vocalization, maximum angle of arytenoid cartilage, axon number of distal part of RLN, and expression of the brain-derived neurotrophic factor (BDNF) in right thyroarytenoid muscle were evaluated at different time points, including 4, 8, and 12 weeks after operation. ResultsGrade of vocalization, maximum angle of arytenoid cartilage, axon numbers of distal part of RLN, and the expression of BDNF in the right thyroarytenoid muscle of experiment group were all lower than those corresponding index of blank control group (P < 0.05), and these indexes of experiment group were restored gradually with time, but failed to reach normal level during the observed time. ConclusionsEven though spontaneous reinnervation is presented after RLN injury, but the effect is unsatisfactory.