OBJECTIVE Following the delayed repair of peripheral nerve injury, the cell number of anterior horn of the spinal cord and its ultrastructural changes, motorneuron and its electrophysiological changes were investigated. METHODS In 16 rabbits the common peroneal nerves of both sides being transected one year later were divided into four groups randomly: the degeneration group and regeneration of 1, 3 and 5 months groups. Another 4 rabbits were used for control. All transected common peroneal nerves underwent epineural suture except for the degeneration group the electrophysiological examination was carried out at 1, 3 and 5 months postoperatively. Retrograde labelling of the anterior horn cells was demonstrated and the cells were observed under light and electronmicroscope. RESULTS 1. The number of labelled anterior horn cell in the spinal cord was 45% of the normal population after denervation for one year (P lt; 0.01). The number of labelled cells increased steadily from 48% to 57% and 68% of normal values at 1, 3 and 5 months following delayed nerve repair (P lt; 0.01). 2. The ultrastructure of the anterior horn cells of the recover gradually after repair. 3. With the progress of regeneration the latency become shortened, the conduction velocity was increased, the amplitude of action potential was increased. CONCLUSION Following delayed repair of injury of peripheral nerve, the morphology of anterior horn cells of spinal cord and electrophysiological display all revealed evidence of regeneration, thus the late repair of injury of peripheral nerve was valid.
ObjectiveTo analyze the protective mechanism of spinal cord ischemia-reperfusion injury mediated by N-methyl-D-aspartate (NMDA) receptor.MethodsA total of 42 SD rats were randomly assigned to 4 groups: a non-blocking group (n=6), a saline group (n=12), a NMDA receptor blocker K-1024 (25 mg/kg) group (n=12) and a voltage-gated Ca2+ channel blocker nimodipine (0.5 mg/kg) group (n=12). The medications were injected intraperitoneally 30 min before ischemia. The neural function was evaluated. The neuronal histologic change of spinal cord lumbar region, the release of neurotransmitter amino acids and expression of spinal cord neuronal nitric oxide synthase (nNOS) were compared.ResultsAt 8 h after reperfusion, the behavioral score of the K-1024 group was 2.00±0.00 points, which was statistically different from those of the saline group (5.83±0.41 points) and the nimodipine group (5.00±1.00 points, P<0.05). Compared with the saline group and nimodipine group, K-1024 group had more normal motor neurons (P<0.05). There was no significant difference in glutamic acid concentration in each group at 10 min after ischemia (P=0.731). The nNOS protein expression in the K-1024 group was significantly down-regulated compared with the saline group (P<0.01). After 8 h of reperfusion, the expression of nNOS protein in the K-1024 group was significantly up-regulated compared with the saline group (P<0.05).ConclusionK-1024 plays a protective role in spinal cord ischemia by inhibiting NMDA receptor and down-regulating nNOS protein expression; during the reperfusion, K-1024 has a satisfactory protective effect on spinal cord function, structure and biological activity of nerve cells.
The purpose of this study was to identify specific microRNAs (miRNAs) during differentiation and maturation of interneurons and to predict their possible functions by analyzing the expression of miRNAs during in vitro differentiation of the rat interneuron precursor cell line GE6. In the experiment, the interneuron precursor cell line GE6 was cultured under three different conditions, i.e. the first was that had not added growth factors and the normal differentiation cultured for 4 days (Ge6_4d); the second was that cultured with bone morphogenetic protein-2 (BMP2) for 4 days (Ge6_bmp2); and the third was that cultured with sonic hedgehog (SHH) for 4 days (Ge6_shh). In addition, another group of undifferentiated GE6 (Ge6_u) was applied as a control. We found in this study that the expression levels of a large number of miRNAs changed significantly during GE6 differentiation. The expression levels of miR-710, miR-290-5p and miR-3473 increased in the GE6 cells with secreted factor BMP2. These miRNAs may play important regulatory roles during interneuron differentiation.
To investigate the mechanism of cAMP/Ca2+ signaling pathway inducing bone marrow mesenchymal stem cells to differentiate into neuronal cells, we cultured the bone marrow mesenchymal stem cells D1 cells in the present study. D1 cells were divided into two groups: control group and salidroside inducing groups. Control group was cultured with complete culture solution D/F12, while salidroside inducing groups were induced with 100 mg·L–1 salidroside for different time periods (24, 48 and 72 hours). PCR-array assay was used to detect expression of 84 calcium related mRNA, and significantly different genes were chosen to analyse. As a result, there were 4 significantly upregulated mRNAs inclu-ding DNA damage-inducible transcript 3 (Ddit3), heat shock protein 5 (Hspa5), protein phosphatase 1 regulatory subunit (Ppp1r15a) and prostaglandin-endoperoxide synthase 2 (Ptgs-2), and 4 significantly downregulated mRNAs including glucagon (Gcg), interleukin 2 (Il2), tumor necrosis factor (Tnf) and somatostatin (Sst) in the cAMP/Ca2+ signaling pathway. They probably had an effect on the process of salidroside induced D1 cells differentiating into neuronal cells.
ObjectiveTo illustrate the role of epidermal growth factor (EGF) secreted by astrocytes in the process of tacrolimus (FK506) in promoting neurite outgrowth.
MethodsThe spinal cord astrocytes and neuronal cells were isolated respectively from 2-day-old Sprague Dawley (SD) rats and 15-day SD pregnant rats, and cultured in vitro and identified by immunofluorescence staining. The spinal cord astrocytes were cultured with 20 μmol/L FK506 medium in the experimental group, and with FK506 free medium in the control group. The supernatant was collected after 24 hours for preparing conditioned medium, and astrocytes were collected. EGF proteins in the conditioned medium were detected with ELISA, and EGF gene expressions of astrocytes were detected with real-time quantitative PCR (RT-qPCR). The spinal cord neurons were cultured respectively with conditioned medium from the experimental group (FK506-CM) and the control group (C-CM) in group A and group B, also with neutralized C-CM and neutralized FK506-CM with anti-EGF neutralizing antibodies in group C and group D. Both the total neurite length and the longest neurite length were measured and compared among groups.
ResultsBoth astrocytes and neurons were confirmed by immunofluorescence staining. The EGF content of experimental group (0.241±0.044) was significantly higher than that of the control group (0.166±0.014) (t=3.93, P=0.01); EGF gene expression of the experimental group (1.12±0.25) was significantly higher than that of the control group (0.46±0.11) (t=5.78, P=0.00). The neurite length measurement displayed that the total neurite length and the longest neurite length of groups C and D were significantly shorter than those of groups A and B (P<0.05). Both the total and longest neurite length of group A were significantly longer than those of group B (P<0.05), but no significant difference was shown between groups C and D (P>0.05).
ConclusionThe EGF secreted by spinal cord astrocytes can promote the neurite outgrowth. So spinal cord astrocytes can be used as an important intermediary target of FK506 to promote the recovery of neurological function.
ObjectiveTo explore the correlation between the functional status of upper limb motor neurons and motor function in stroke patients, and provide guidance for rehabilitation assessment and functional prognosis.MethodsThe stroke patients who were hospitalized in Department of Rehabilitation Medicine of Zhongda Hospital of Southeast University between November 2020 and January 2021 were selected. Motor unit number estimation (MUNE) and F wave were examined to evaluate the functional status of motor neuron. The Fugl-Meyer Assessment (FMA) and Modified Ashworth Scale (MAS) were used to evaluate the upper limb motor function. The correlations of electrophysiological parameters with FMA score and MAS score were analyzed respectively.ResultsA total of 42 patients were enrolled, and 16 patients were complicated with carpal flexor spasm on the affected side. Among the 42 stroke patients, the MUNE of the abductor pollicis brevis on the affected side was lower than that on the unaffected side (t=?3.466, P=0.001), and the percentage of F waves with different shapes on the affected side was significantly lower than that on the unaffected side (Z=?5.583, P<0.001). Among the 16 stroke patients with carpal flexor spasm, the F wave amplitude was higher on the affected side than that on the unaffected side (t=2.764, P=0.014), while the F wave latency on the affected side was not statistically significant compared with the unaffected side (Z=?0.595, P=0.552). Among the 42 stroke patients, the affected/unaffected side ratio of the percentage of F waves with different shapes was positively correlated with FMA score (rs=0.377, P=0.014), while the correlation between the affected/unaffected side ratio of MUNE and FMA score was not statistically significant (rs=0.104, P=0.513). Among the 16 stroke patients with carpal flexor spasm, the affected/unaffected side ratio of the F wave amplitude was positively correlated with the MAS score of the carpi flexor muscle (rs=0.550, P=0.027).ConclusionStroke may result into the number of functional motor neurons of the upper limbs of the hemiplegic side decreased and the excitability of motor neurons increased simultaneously, and which were related to motor function and muscle tone.
The translation and translation regulation of RNA in eukaryotic cells have a significant impact on cellular gene expression and maintenance of proteomic homeostasis. Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects upper and lower motor neurons and leads to muscle weakness and atrophy. More and more studies have found RNA translation abnormalities in ALS. This article provides an overview of RNA translation and regulation in eukaryotic cells under physiological and stress conditions, and explores the relationship between four different ALS-related genes and translation abnormalities, providing new ideas for the treatment of ALS.
Objective To explore the changes of morphology and ventricornual motor neuronsin SD rats’ ventral horn of spinal cord after radiated as the therapy protocol for breast cancer, to discover the rule of radiationinduced injury of brachialplexus, and also if there exits the reversible conversion in neurons. Methods Twenty SD rats were selected. The left side of the rats was used as the radiation side, and the right side as the control side. The RIBPI animal models were established by divideddose of radiation. Using 2 Gy/time and 5 times/week, a total administered dose reached 30 Gy after 3 weeks. The behaviour of the rats was observed after radiation. At 3, 5, 7 and 9 weeks after the last radiation (n=4), the wet weights of biceps brachii muscle, upperlimb circumference and compound action potential were examined; the pathological changes of biceps brachiimuscle, the morphological changes, counts of the motor neurons in ventral horn and axons of bilateral spinal cord were observed by HE staining, argentums staining and toluidine blue staining. Results The rats showed lameness and a “claw hand” 3 weeks after radiation. Compared with control side, thewet weights of biceps brachii muscle and upperlimb circumference were significantly reduced, meanwhile, the compound action potential significantly decreased, and its latent period was also significantly prolonged 3, 5, 7 and 9 weeks (Plt;0.05). The histological observation: Musculocutaneous nerve showed decreased medullated fibers, heterogeneous ditribution and decreased density, thin myelin sheath, damaged nerve structure and collagen hyperplasia; biceps brachii muscle showed degeneration, fiber breakage and inflammatory cell infiltration; The account of motor neurons in ventral horn was significantly decreased in the radiation side with time extending, the sign of cell death, such as, the neurons crimple, and karyolysis were observed(Plt;0.05). Conclusion Large dose of X-ray can inducedbrachial plexus injury, and the lameness, a “claw hand”, biceps brachii muscle atrophy and the compound action potential abnormality. The account of motor neurons in ventral horn was significantly decreased. The motor neurons showed oxonal degeneration and myelinec degeration.
ObjectiveTo observe the morphological and functional changes of retinal degeneration in mice with CLN7 neuronal ceroid-lipofuscinosis, and the therapeutic effects of glial cell derived neurotrophic factor (GDNF) and/or ciliary neurotrophic factor (CNTF) based on neural stem cells (NSC) on mouse photoreceptor cells. MethodsA total of 100 CLN7 mice aged 14 days were randomly divided into the experimental group and the control group, with 80 and 20 mice respectively. Twenty C57BL/6J mice aged 14 days were assigned as wild-type group (WT group). Mice in control group and WT group did not receive any interventions. At 2, 4, and 6 months of age, immunohistochemical staining was conducted to examine alterations in the distribution and quantity of cones, rod-bipolar cells, and cone-bipolar cells within the retinal of mice while electroretinography (ERG) examination was utilized to record scotopic a and b-waves and photopic b-wave amplitudes. At 14 days of age, the mice in the experimental group were intravitreally injected with 2 μl of CNTF-NSC, GDNF-NSC, and a 1:1 cell mixture of CNTF-NSC and GDNF-NSC (GDNF/CNTF-NSC). Those mice were then subdivided into the CNTF-NSC group, the GDNF-NSC group, and the GDNF/CNTF-NSC group accordingly. The contralateral eyes of the mice were injected with 2 μl of control NSC without neurotrophic factor (NTF) as their own control group. At 2 and 4 months of age, the rows of photoreceptor cells in mice was observed by immunohistochemical staining while ERG was performed to record amplitudes. At 4 months of age, the differentiation of grafted NSC and the expression of NTF were observed. Statistical comparisons between the groups were performed using a two-way ANOVA. ResultsCompared with WT group, the density of cones in the peripheral region of the control group at 2, 4 and 6 months of age (F=285.10), rod-bipolar cell density in central and peripheral retina (F=823.20, 346.20), cone-bipolar cell density (F=356.30, 210.60) and the scotopic amplitude of a and b waves (F=1 911.00, 387.10) in central and peripheral retina were significantly decreased, with statistical significance (P＜0.05). At the age of 4 and 6 months, the density of retinal cone cells (F=127.30) and b-wave photopic amplitude (F=51.13) in the control group were significantly decreased, and the difference was statistically significant (P＜0.05). Immunofluorescence microscopy showed that the NSC transplanted in the experimental group preferentially differentiated into astrocytes, and stably expressed CNTF and GDNF at high levels. Comparison of retinal photoreceptor nucleus lines in different treatment subgroups of the experimental group at different ages: CNTF-NSC group, at 2 months of age: the whole, central and peripheral regions were significantly different (F=31.73, 75.06, 75.06; P＜0.05); 4 months of age: The difference between the whole area and the peripheral region was statistically significant (F=12.27, 12.27; P＜0.05). GDNF/CNTF-NSC group, 2 and 4 months of age: the whole (F=27.26, 27.26) and the peripheral area (F=16.01, 13.55) were significantly different (P＜0.05). In GDNF-NSC group, there was no statistical significance at all in the whole, central and peripheral areas at different months of age (F=0.00, 0.01, 0.02; P＞0.05). ConclusionsCLN7 neuronal ceroid-lipofuscinosis mice exhibit progressively increasing degenerative alterations in photoreceptor cells and bipolar cells with age growing, aligning with both morphological and functional observations. Intravitreal administration of stem cell-based CNTF as well as GDNF/CNTF show therapeutic potential in rescuing photoreceptor cells. Nevertheless, the combined application of GDNF/CNTF-NSC do not demonstrate the anticipated synergistic protective effect. GDNF has no therapeutic effect on the retinal morphology and function in CLN7 neuronal ceroid-lipofuscinosis mice.
Objective To investigate the survival effect and reaction mechanismsof motor neurons after reimplantation of the avulsed root into the spinal cord,and to observe the survival and differentiation in the spinal cord after brachial plexus roots avulsion. Methods Thirty adult Wistar rats were randomly devided into the control group and the experimental group (n=15). Laminectomy of C4-6 was performed via a posterior approach. The ventral and dorsal roots of C5，6 were both avulsed from the spinal cord outside the dura mater and within the vertebral canal.For the experimental group, the ventral root of C6 wasreimplanted into the ventralhorn under microscope. The dorsal root was left. The ventral and dorsal roots of C5 were placed inside the nearby muscles. For the control group, the ventral and dorsal roots of both C5 and C6 were placed inside the nearby muscles. At 2, 4, 6, 8, 12 weeks postoperatively, the C6 spinal cord was stained with HE. The changes of the number and morphology of motor neurons were observed onHEstained sections. The C6 spinal nerve root was stained with silver nitrate, andthe regeneration of nerve fiber was observed. Results All rats were recovered well and their wounds were healed at primary stage. The gross observation showed that the avulsed nerve roots in control group adhered to adjacent muscles, however the one in experimental groups which had been implanted into spinal cord adhered to scar tissues and were not separated from spinal cord. At each time point postoperatively, the HEstained transverse sections showed that the number of motor neurons decreased significantly with soma swollen and atrophied, Nissle bodies decreased or disappeared. The survival rates of motor neurons in the control group were 60.9％±5.8%,42.3％±3.5％,30.6％±6.1％27.5％±7.9％ and 20.4％±6.8％ respectively；in the experimental group,the survival rates were 67.1％±7.4％,56.3％±4.6％,48.7％±8.8％,44.2％±5.5％ and 42.5％±8.3％ respectively. The survival rates of motor neurons in the experimental group was higher than those in the control group at all time points,showing statistically significant difference（Plt;0.01）.At 12 weeks postoperatively, thesilver nitrate stained specimen from the C6 nerve root showed regeneration of the motor neurons in the ventral horn into the reimplanted nerve root through axon in the experimental group,but the degeneration of the nerve fiber appeared and the number of the myelinated nerve fiber decreased in the control group. Conclusion Through reimplantationof the avulsed ventral nerve root into the ventral horn, degeneration of the motor neurons in the ventral horn can be reduced. After reimplantation of avulsed nerve root, there is axonal regrowth of motor neurons into the spinal nerve root and regeneration of the myelinated nerve fiber also appears.
