Objective To establish a better method of isolating andculturing ofneural stem cells(NSCs) in neonatal rat brain. Methods Tissue of brain was isolated from neonatal rats. Different medium and culture concentration were used toculture NSCs of neonatal rat. The culture concentration used were 1×10 4, 1×105, 1×106and 1×107/ml respectively. Ingredient of medium was classified into group 1 to 8 respectively according to whether to add 2% B27, epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) as well as the difference in culture concentration. The cells were induced to differentiate asto be confirmed as NSCs, and then were checked by phase contrast microscopy and identified by immunocytochemistry. Results The cells isolated and cultured gathered into neurospheres. The cells were capable of proliferating and maintaining longterm survival in vitro. The cells could be differentiated into neurons and glia.It was to the benefit of the survival of NSCs to add 5% fetal bovine serum(FBS)into the medium at the beginning of the culturing. When 10% FBS was added intothe medium, the neurospheres differentiated quickly. When concentration 1×106/ ml was used, the growth rate of the cells was the highest of all the concentrations. Reasonably higher cell concentration promoted the proliferation of NSCs. It was necessary to add 2% B27, EGF, and bFGF into the medium. The cells had the best growth when 2% B27, 20 ng/ml bFGF and 20 ng/ml EGF were added into the culture medium. EGF and bFGF had cooperative effect. Conclusion A better method of isolating and culturing of NSCs in neonatal rat brain is established and the foundation for future research is laid.
ObjectiveTo observe the effect of transplantation of neural stem cells (NSCs) induced by all-trans-retinoic acid (ATRA) combined with glial cell line derived neurotrophic factor (GDNF) and chondroitinase ABC (ChABC) on the neurological functional recovery of injured spinal cord in Sprague Dawley (SD) rats.
MethodsSixty adult SD female rats, weighing 200-250 g, were randomly divided into 5 groups (n=12): sham operation group (group A), SCI model group (group B), NSCs+GDNF treatment group (group C), NSCs+ChABC treatment group (group D), and NSCs+GDNF+ChABC treatment group (group E). T10 segmental transversal injury model of the spinal cord was established except group A. NSCs induced by ATRA and marked with BrdU were injected into the site of injury at 8 days after operation in groups C-E. Groups C-E were treated with GDNF, ChABC, and GDNF+ChABC respectively at 8-14 days after operation;and group A and B were treated with the same amount of saline solution. Basso Beattie Bresnahan (BBB) score and somatosensory evoked potentials (SEP) test were used to study the functional improvement at 1 day before remodeling, 7 days after remodeling, and at 1, 2, 5, and 8 weeks after transplantation. Immunofluorescence staining and HE staining were performed to observe the cells survival and differentiation in the spinal cord.
ResultsFive mouse died but another rats were added. At each time point after modeling, BBB score of groups B, C, D, and E was significantly lower than that of group A, and SEP latent period was significantly longer than that of group A (P<0.05), but no difference was found among groups B, C, D, and E at 7 days after remodeling and 1 week after transplantation (P>0.05). BBB score of groups C, D, and E was significantly higher than that of group B, and SEP latent period was significantly shorter than that of group B at 2, 5, and 8 weeks after transplantation (P<0.05);group E had higher BBB score and shorter SEP latent period than groups C and D at 5 and 8 weeks, showing significant difference (P<0.05). HE staining showed that there was a clear boundary between gray and white matter of spinal cord and regular arrangement of cells in group A;there were incomplete vascular morphology, irregular arrangement of cells, scar, and cysts in group B;there were obvious cell hyperplasia and smaller cysts in groups C, D, and E. BrdU positive cells were not observed in groups A and B, but could be found in groups C, D and E. Group E had more positive cells than groups C and D, and difference was significant (P<0.05). The number of glial fibrillary acidic protein positive cells of groups C, D, and E was significantly less than that of groups A and B, and it was significantly less in group E than groups C and D (P<0.05). The number of microtubule-associated protein 2 positive cells of groups C, D, and E was significantly more than that of groups A and B, and it was significantly more in group E than groups C and D (P<0.05).
ConclusionThe NSCs transplantation combined with GDNF and ChABC could significantly promote the functional recovery of spinal cord injury, suggesting that GDNF and ChABC have a synergistic effect in the treatment of spinal cord injury.
Objective To observe the biocompatibil ity of self-assembled FGL peptide nano-fibers scaffold with neural stem cells (NSCs). Methods FGL peptide-amphiphile (FGL-PA) was synthesized by sol id-phase peptide synthesistechnique and thereafter It was analyzed and determined by high-performance l iquid chromatography (HPLC) and massspectrometry (MS). The diluted hydrochloric acid was added into FGL-PA solution to reduce the pH value and accordinglyinduce self-assembly. The morphological features of the assembled material were studied by transmission electron microscope (TEM). NSCs were cultured and different concentrations of FGL-PA assembled material were added with the terminal concentrations of 0, 50, 100, 200, 400 mg/L, respectively. CCK-8 kit was used to test the effect of FGL assembled material on prol iferation of NSCs. NSCs were added into differentiation mediums (control group: DMEM/F12 medium containing 2% B27 supplement and 10% FBS; experimental group: DMEM/F12 medium containing 2% B27 supplement, 10% FBS and 100 mg/L FGL-PA, respectively). Immunofluorescence was appl ied to test the effect of FGL-PA assembled material on differentiation of NSCs. Results FGL-PA could be self-assembled to form a gel. TEM showed the self-assembled gel was nano-fibers with diameter of 10-20 nm and length of hundreds nanometers. After NSCs were incubated for 48 hours with different concentrations of FGL-PA assembled material, the result of CCK-8 assay showed that FGL-PA with concentrations of 50, 100 or 200 mg/L could promote the prol iferation of NSCs and absorbance of them was increased (P lt; 0.05). Immunofluorescence analysis notified that the differentiation ratio of neurons from NSCs in control group and experimental group were 46.35% ± 1.27% and 72.85% ± 1.35%, respectively, when NSCs were induced to differentiation for 14 days, showing significant difference between 2 groups (P lt; 0.05). Conclusion FGL-PA can self-assemble to nano-fiber gel, which has good biocompatibil ity and neural bioactivity.
Objective To investigate the division, prol iferation and differentiation abil ities of nestin+/GFAP+cell after spinal cord injury and to identify whether it has the characteristic of neural stem cells (NSCs). Methods Twelvemale SD rats, aged 8 weeks and weighing 200-250 g, were randomized into 2 groups (n=6 per group): model group inwhich the spinal cord injury model was establ ished by aneurysm cl ip compression method, and control group in which no processing was conducted. At 5 days after model ing, T8 spinal cord segment of rats in each group were obtained and the gray and the white substance of spinal cord outside the ependymal region around central tube were isolated to prepare single cellsuspension. Serum-free NSCs culture medium was adopted to culture and serum NSCs culture medium was appl ied to induce differentiation. Immunohistochemistry detection and flow cytometry were appl ied to observe and analyze the type of cells and their capabil ity of division, prol iferation and differentiation. Results At 3-7 days after injury, the model group witnessed a plenty of nestin+/GFAP+ cells in the single cell suspension, while the control group witnessed few. Cell count of the model and the control group was 5.15 ± 0.71 and 1.12 ± 0.38, respectively, indicating there was a significant difference between two groups (P lt; 0.01). Concerning cell cycle, the proportion of S-phase cell and prol iferation index of the model group (15.49% ± 3.04%, 15.88% ± 2.56%) were obviously higher than those of the control group (5.84% ± 0.28%, 6.47% ± 0.61%), indicating there were significant differences between two groups (P lt; 0.01). In the model group, primary cells gradually formed threedimensional cell clone spheres, which were small in size, smooth in margin, protruding in center and positive for nestin immunofluorescence staining, and large amounts of cell clone spheres were harvested after multi ple passages. While in the control group, no obvious cell clone spheres was observed in the primary and passage culture of single cell suspension. At 5 days after induced differentiation of cloned spheres in the model group, immunofluorescence staining showed there were a number of galactocerebroside (GaLC) -nestin+ cells; at 5-7 days, there were abundance of β-tubul in III-nestin+ and GFAP-nestin+ cells; and at 5-14 days, GaLC+ ol igodendrocyte, β-tubul in II+ neuron and GalC+ cell body and protruding were observed. Conclusion Nestin+/GFAP+ cells obtained by isolating the gray and the white substance of spinal cord outside the ependymal region around central tube after compressive spinal cord injury in adult rat has the abil ity of self-renewal and the potential of multi-polarization and may be a renewable source of NSCs in the central nervous system.
Neural stem cell is a kind of stem cells that can differentiate into neural and glial cells. While Müller cells, the main endogenous neural stem cell in retina,have the features to reentry into the cell cycle and differentiate into neural cells after retinal damage. Although it is highly effective for retinal Müller cell differentiation spontaneously after retinal injury in vertebrates, this feature is rigorous restricted in mammals. Recently, some transcription factors,such as Ascl1, Sox2, Lin28, Atoh7, are sufficient to drive quiescent Müller cells back in proliferation to generate new retinal neurons. Moreover, combining Ascl1 expression with a histone deacetylase inhibitor can bypass the limitation and increase the generation of new neurons in the adult retina. These regenerated neurons integrate the existing neuronal network and are able to respond to light, indicating that they can likely be used to restore vision. While these results are extremely promising, the regenerative response is still limited, likely because the proliferative capacity of mammalian Müller cells is low compared to their zebrafish counterparts. It is indeed necessary to identify new factors increasing the efficiency of the regenerative response.
ObjectiveTo observe the effects on the function and structure of retina in diabetic rats by intravitreal transplantation of retinal nerve stem cells (NSC) differentiated from human umbilical cord mesenchymal stem cells (hUCMSCs).
MethodsFifty clean male Sprague-Dawley rats were randomly divided into normal control with 9 rats (group A) and diabetes mellitus (DM) group with 31 rats. The DM models were induced by intraperitoneal injection of streptozocin. The rats of DM group were randomly divided into four groups after 10 weeks: rats with DM only (group B), diabetic rats with saline intravitreal injection (group C), diabetic rats with NSC intravitreal injection (group D), and 9 rats for each. The rats in the group A and B received no treatment. The retinal function was examined by the flash-electroretinogram on 2, 4, 6 weeks after intervention, the latency and amplitude of a-wave, b-wave of Rod, a-wave, b-wave of Max reactions (Max-R) and the total amplitudes of OPs were recorded. The morphological changes of retina were observed by hematoxylin-eosin staining.
ResultsOn 2 and 4 weeks after the intervention, the differences of latency and amplitude of b-wave of Rod, a-wave, b-wave of Max-R and the total amplitudes of OPs among group A-D were significant (P<0.05). Compared group D with group B, C, the amplitude of b-wave of Rod, Max-R and the total amplitudes of OPs were increased (P<0.05); latency of b-wave of Max-R was decreased (P<0.05). On 6 weeks after the intervention, the amplitude of b-wave of Rod and the amplitude of a-wave, b-wave of Max-R and the total amplitudes of OPs in group D were increased compared with group B and C (P<0.05), the latency of b-wave of Rod and Max-R in group D were decreased compared with group C (P<0.05). On 10 weeks after molding, each retinal layers were disordered in diabetes mellitus group. On 2 weeks after the intervention, the number of cells in the retinal layers in group B and C were reduced compared with group A, and the structure was more disorder. On 4 weeks after the intervention, the structure of each retina layer in group D arranged less disordered, and the number of retinal ganglion cells was more than group B and C. It was also found that the retinal vascular endothelial expanded and retinal blood vessels cells proliferated.
ConclusionThe function of retina in diabetes mellitus rats is improved by intravitreal injection of retinal NSCs differentiated from hUCMSCs.
Objective To observe the delaying effect of neural stem cell (NSC) transplantation on denervated muscle atrophy after peri pheral nerve injury, and to investigate its mechanism. Methods NSCs were separated from the spinal cords of green fluorescent protein (GFP) transgenic rats aged 12-14 days mechanically and were cultured and induced to differentiate in vitro. Thirty-two F344 rats, aged 2 months and weighed (180 ± 20) g, were randomized into two groups (n=16 per group). The animal models of denervated musculus triceps surae were establ ished by transecting right tibial nerve and commom peroneal nerve 1.5 cm above the knee joints. In the experimental and the control group, 5 μL of GFP-NSCsuspension and 5 μL of culture supernatant were injected into the distal stump of the tibial nerve, respectivel. The generalcondition of rats after operation was observed. At 4 and 12 weeks postoperatively, the wet weight of right musculus tricepssurae was measured, the HE staining, the Mallory trichrome staining and the postsynaptic membrane staining were adopted for the histological observation. Meanwhile, the section area of gastrocnemius fiber and the area of postsynaptic membrane were detected by image analysis software and statistical analysis. Results The wounds in both groups of animals healed by first intension, no ulcer occurred in the right hind l imbs. At 4 and 12 weeks postoperatively, the wet weight of right musculus triceps surae was (0.849 ± 0.064) g and (0.596 ± 0.047) g in the experimental group, respectively, and was (0.651 ± 0.040) g and (0.298 ± 0.016) g in the control group, respectively, showing a significant difference (P lt; 0.05). The fiber section area of the gastrocnemius was 72.55% ± 8.12% and 58.96% ± 6.07% in the experimental group, respectively, and was 50.23% ± 4.76% and 33.63% ± 4.41% in the control group, respectively. There were significant differences between them (P lt; 0.05). Mallory trichrome staining of muscle notified that there was more collagen fiber hyperplasia of denervated gastrocnemius in the control group than that in the experimental group at 4 and 12 weeks postoperatively. After 12 weeks of operation, the area of postsynaptic membrane in the experimental group was (137.29 ± 29.14) μm2, which doubled that in the control group as (61.03 ± 11.38) μm2 and was closer to that in normal postsynaptic membrane as (198.63 ± 23.11) μm2, showing significant differences (P lt; 0.05). Conclusion The transplantation in vivo of allogenic embryonic spinal cord NSCs is capable of delaying denervated muscle atrophy and maintaining the normal appearance of postsynaptic membrane, providing a new approach to prevent and treat the denervated muscle atrophy cl inically.
ObjectiveTo prepare bionic spinal cord scaffold of collagen-heparin sulfate by three-dimensional (3-D) printing, and provide a cell carrier for tissue engineering in the treatment of spinal cord injury.
MethodsCollagen-heparin sulfate hydrogel was prepared firstly, and 3-D printer was used to make bionic spinal cord scaffold. The structure was observed to measure its porosity. The scaffold was immersed in simulated body fluid to observe the quality change. The neural stem cells (NSCs) were isolated from fetal rat brain cortex of 14 days pregnant Sprague-Dawley rats and cultured. The experiment was divided into 2 groups: in group A, the scaffold was co-cultured with rat NSCs for 7 days to observe cell adhesion and morphological changes;in group B, the NSCs were cultured in 24 wells culture plate precoating with poly lysine. MTT assay was used to detect the cell viability, and immunofluorescence staining was used to identify the differentiation of NSCs.
ResultsBionic spinal cord scaffold was fabricated by 3-D printer successfully. Scanning electron microscope (SEM) observation revealed the micro porous structure with parallel and longitudinal arrangements and with the porosity of 90.25%±2.15%. in vitro, the value of pH was not changed obviously. After 8 weeks, the scaffold was completely degraded, and it met the requirements of tissue engineering scaffolds. MTT results showed that there was no significant difference in absorbence (A) value between 2 groups at 1, 3, and 7 days after culture (P>0.05). There were a lot of NSCs with reticular nerve fiber under light microscope in 2 groups;the cells adhered to the scaffold, and axons growth and neurosphere formation were observed in group A under SEM at 7 days after culture. The immunofluorescence staining observation showed that NSCs could differentiated into neurons and glial cells in 2 groups;the differentiation rate was 29.60%±2.68% in group A and was 10.90%±2.13% in group B, showing significant difference (t=17.30, P=0.01).
ConclusionThe collagen-heparin sulfate scaffold by 3-D-printed has good biocompatibility and biological properties. It can promote the proliferation and differentiation of NSCs, and can used as a neural tissue engineered scaffold with great value of research and application.
ObjectiveTo study the possibility of the C17.2 neural stem cells (NSCs) differentiating into neural cells induced by serum-free condition medium of olfactory ensheathing cells (OECs) and to detect the cell viability of the differentiated cells.
MethodsOECs were isloated and cultured from the olfactory bulbs of 3-day-old postnatal mouse to prepare serum-free condition medium of OECs. After C17.2 NSCs were cultured with H-DMEM/F12 medium containing 15% FBS and the cell fusion reached 80%, the 3rd passage cells were induced by serum-free condition medium of OECs in the experimental group, by H-DMEM/F12 in the control group, and non-induced C17.2 NSCs served as the blank control group. The growth condition of cells was observed with inverted microscope. After 5 days, the immunofluorescence staining[microtubule-associated protein 2 (MAP-2) and β-tubulin-Ⅲ] and Western blot (Nestin, β-tubulin-Ⅲ, and MAP-2) were carried out to identify the neural cells derived from NSCs. The cell viabilities were measured by MTT assay and the quantity of lactate dehydrogenase (LDH) release in the medium.
ResultsIn the experimental group, the C17.2 NSCs bodies began to contract at 24 hours after induction, and the differentiated cells increased obviously with long synapse at 3 days after induction; in the control group, the cell morphology showed no obvious change at 24 hours, cell body shrinkage, condensation of nuclear chromatin, and lysis were observed at 3 days. The immunofluorescence staining showed that β-tubulin-Ⅲ and MAP-2 of C17.2 NSCs were positive at 5 days after induction, and Western blot suggested that the expression of Nestin protein declined significantly and the expressions of β-tubulin-Ⅲ and MAP-2 protein were increased in the experimental group, showing significant differences when compared with those in the control group and blank control group (P<0.05). The LDH release and the cell viability were 130.60%±6.86% and 62.20%±3.82% in the experimental group, and were 178.20%±5.44% and 18.00%±3.83% in the control group respectively, showing significant differences between 2 groups (P<0.05). The LDH release and the cell viability of experimental group and control group were significantly lower than those of blank control group (100%) (P<0.05).
ConclusionNeurotrophic factors from OECs play an important role in inducing C17.2 NSCs differentiation into neural cells and keeping the viability of differentiated cells after induction.
To explore the expression of Wnt-1 during the process of inducing neural stem cells (NSCs) into neurons by using all-trans-retinoic acid (ATRA) in vitro and the effect of Wnt-1 on NSCs differentiation. Methods NSCs isolated from cerebral cortex of SD rat embryo (12-16 days’ gestation) were cultured. The concentration of cells at passage 3 were adjusted to 1 × 106 cells /mL and treated with ATRA at 0.5, 1.0, 5.0 and 10.0 μmol/L, respectively. Differentiation ratio of NSCsinto neurons in each group was detected by double-labelling immunofluorescence technique and flow cytometry, and 1.0 μmol/ L was selected as the best concentration for ATRA to promote NSCs differentiation. In experimental group, NSCs at passage 3 were cultured with ATRA at 1.0 μmol/L in vitro, and expression of Wnt-1 was detected by immunocytochemistry staining, realtime flurescent quantitive PCR and Western blot at 3, 5, 7 and 9 days after culture, respectively. The cells at passage 3 receiving no ATRA served as control group. Results Immunocytochemistry staining: in the control group, there was l ittle Wnt-1 protein expression; in the experimental group, peak expression of Wnt-1 and numerous positive cells occurred at 3 days after culture, the positive expression of Wnt-1 was still evident at 5 days after culture, and there was significant difference between two groups in integrated absorbance (IA) value at 3 and 5 days after culture(P lt; 0.05), obvious decrease of positive expression of Wnt-1 was evident, and no significant difference was evident between two groups in IA value at 7 and 9 days (P gt; 0.05). Real-time fluorescence quantitative PCR: the relative expression of Wnt-1 mRNA in the control group was 0.021 7 ± 0.072 1; the relative expression of Wnt-1 mRNA in the experimental group at 3, 5, 7 and 9 days was 0.512 2 ± 0.280 0, 0.216 4 ± 0.887 0, 0.038 5 ± 0.299 4 and 0.035 5 ± 0.309 5, respectively, indicating the value decreased over time, and there were significant difference between two groups at 3 and 5 days (P lt; 0.05), and no significant difference at 7 and 9 days (P gt; 0.05) . Western blot detection: specific and visible staining band was noted; in the control group, Wnt-1 protein expression was 0.005 1 ± 0.558 3; in the experimental group, Wnt-1 protein expression at 3, 5, 7 and 9 days was 0.451 7 ± 0.071 3, 0.311 7 ± 0.080 5, 0.007 3 ± 0.052 7 and 0.004 7 ± 0.931 4, respectively, suggesting the value decreased over time; there were significant differences between two groups at 3 and 5 days (P lt; 0.05), and no significant differences at 7 and 9 days (P gt; 0.05). Conclusion With the induction of ATRA at 1.0 μmol/L, Wnt-1 and NSCs differentiation in early stage are positively correlated. Its possible mechanism may rely on the activation of such signals as classic Wnt-1 signal pathway, indicating Wnt-1 relates to the differentation of NSCs into neurons.
