Construction of hiPSC-derived Excitatory Neural Network-like Tissue / 中山大学学报(医学科学版)

ObjectiveTo construct a neural network-like tissue with the potential of synaptic formation in vitro by seeding human induced pluripotent stem cell-derived neural precursor cells （hiPSC-NPCs） on decellularized optic nerve （DON）， so as to provide a promising approach for repair of nerve tissue injury. MethodsThrough directional induction and tissue engineering technology， human induced pluripotent stem cells （hiPSCs） and 3D DON scaffolds were combined to construct neural network-like tissues. Then the hiPSCs were directionally induced into human neural precursor cells （hNPCs） and neurons. Immunofluorescence staining was used to identify cell differentiation efficiency. 3D DON scaffolds were prepared. Morphology and cytocompatibility of scaffolds were identified by scanning electron microscopy and Tunnel staining. Induced hiPSC-NPCs were seeded on DON scaffolds. Immunofluorescence staining， scanning electron microscopy， transmission electron microscopy and patch clamp were used to observe the morphology and functional identification of constructed neural network tissues. Results①The results of immunofluorescence staining suggested that most of hiPSC-NPCs differentiated into neurons in vitro. We had successfully constructed a neural network dominated by neurons. ② The results of scanning electron microscopy and immunohistochemistry suggested that a neural network-like tissue with predominating excitatory neurons in vitro was successfully constructed. ③The results of immunohistochemical staining， transmission electron microscopy and patch clamp indicated that the neural network-like tissue had synaptic transmission function. ConclusionA neural network-like tissue mainly composed of excitatory neurons has been constructed by the combination of natural uniform-channel DON scaffold and hiPSC-NPCs， which has the function of synaptic transmission. This neural network plays a significant role in stem cell derived replacement therapy， and offers a promising prospect for repair of spinal cord injury （SCI） and other neural tissue injuries.

Construction of iPSC-derived Inhibitory Neural Network Tissue with Synaptic Transmission Potentials / 中山大学学报(医学科学版)

ObjectiveDirected differentiation of human induced pluripotent stem cells （hiPSCs） into spinal cord γ-aminobutyric acid （GABA）-ergic progenitor cells were implanted into an decellularized optical nerve （DON） bioscaffold to construct a hiPSC-derived inhibitory neural network tissue with synaptic activities. This study aimed to provide a novel stem cell-based tissue engineering product for the study and the repair of central nervous system injury. MethodsThe combination of stepwise directional induction and tissue engineering technology was applied in this study. After hiPSCs were directionally induced into human neural progenitor cells （hNPCs） in vitro， they were seeded into a DON for three-dimensional culture， allowing further differentiation into inhibitory GABAergic neurons under the specific neuronal induction environment. Transmission electron microscopy and whole cell patch clamp technique were used to detect whether the hiPSCs differentiated neurons could form synapse-like structures and whether these neurons had spontaneous inhibitory postsynaptic currents， respectively， in order to validate that the hiPSC-derived neurons would form neural networks with synaptic transmission potentials from a structural and functional perspective. ResultsThe inhibitory neurons of GABAergic phenotype were successfully induced from hiPSCs in vitro， and maintained good viability after 28 days of culture. With the transmission electron microscopy， it was observed that many cell junctions were formed between hiPSC-derived neural cells in the three-dimensional materials， some of which presented a synapse- like structure， manifested as the slight thickness of cell membrane and a small number of vesicles within one side of the cell junctions， the typical structure of a presynatic component， and focal thickness of the membrane of the other side of the cell junctions， a typical structure of a postsynaptic component. According to whole-cell patch-clamp recording， the hiPSC-derived neurons had the capability to generate action potentials and spontaneous inhibitory postsynaptic currents were recorded in this biotissue. ConclusionsThe results of this study indicated that hiPSCs can be induced to differentiate into GABAergic progenitor cells in vitro and can successfully construct iPSC-derived inhibitory neural network tissue with synaptic transmission after implanted into a DON for three-dimensional culture. This study would provide a novel neural network tissue for future research and treatment of central nervous system injury by stem cell tissue engineering technology.

Pretreatment with Rhodiola rosea extract reduces cognitive impairment induced by intracerebroventricular streptozotocin in rats: implication of anti-oxidative and neuroprotective effects / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the pretreatment effects of Rhodiola rosea (R. rosea) extract on cognitive dysfunction, oxidative stress in hippocampus and hippocampal neuron injury in a rat model of Alzheimer's disease (AD).</p><p><b>METHODS</b>Male Sprague-Dawley rats were pretreated with R. rosea extract at doses of 1.5, 3.0, and 6.0 g/kg for 3 weeks, followed by bilateral intracerebroventricular injection with streptozotocin (1.5 mg/kg) on days 1 and 3. Behavioral alterations were monitored after 2 weeks from the lesion using Morris water maze task. Three weeks after the lesion, the rats were sacrificed for measuring the malondialdehyde (MDA), glutathione reductase (GR) and reduced glutathione (GSH) levels in hippocampus and histopathology of hippocampal neurons.</p><p><b>RESULTS</b>The MDA level was significantly increased while the GR and GSH levels were significantly decreased with striking impairments in spatial learning and memory and severe damage to hippocampal neurons in the model rat induced by intracerebroventricular injection of streptozotocin. These abnormalities were significantly improved by pretreatment with R. rosea extract (3.0 g/kg).</p><p><b>CONCLUSION</b>R. rosea extract can protect rats against cognitive deficits, neuronal injury and oxidative stress induced by intracerebroventricular injection of streptozotocin, and may be used as a potential agent in treatment of neurodegenerative diseases such as AD.</p>

Effects of Rhodiola rosea on level of 5-hydroxytryptamine, cell proliferation and differentiation, and number of neuron in cerebral hippocampus of rats with depression induced by chronic mild stress / 中国中药杂志

<p><b>OBJECTIVE</b>To explore the effects of Rhodiola rosea on the level of 5-hydroxytryptamine (5-HT), cell proliferation and differentiation, and number of neuron in cerebral hippocampus of rats with depression induced by chronic mild stress.</p><p><b>METHOD</b>Fifty rats were divided into 5 groups: normal control, untreated, negative control, positive control and Rhodiola rosea-treated groups. There were 10 rats in each group. Except for normal control group, depression was induced in rats by chronic mild stress. The depressive rats in the other four groups were intragastrically administered with 0.5% sodium carboxymethycellulose, fluoxetine and Rhodiola rosea for 3 weeks. After the treatment, the content of 5-HT in the hippocampus was detected by high-performance liquid chromatography. The proliferating cells and differentiated cells in the hippocampus were labeled by bromodeoxyuridine (BrdU) or/and beta-tubulin III immunohistochemistry, and the number of hippocampal neurons was counted by morphometry.</p><p><b>RESULT</b>Compared with the normal control group, the content of 5-HT, number of BrdU positive cells, percentage of BrdU and beta-tubulin III double labeled cells and number of neurons in cerebral hippocampus in the Rhodiola rosea-treated group were increased and recovered to normal level.</p><p><b>CONCLUSION</b>Rhodiola rosea may enhance the level of 5-HT and promote the proliferation and differentiation of neural stem cells in the hippocampus of the depressive rats, and may play a role in saving injured neurons of the hippocampus.</p>

Synergistic effect of schwann cells and retinoic acid on differentiation and synaptogenesis of hippocampal neural stem cells in vitro / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the synergistic effect of Schwann cells (SCs) and retinoic acid (RA) on differentiation and synaptogenesis of neural stem cells (NSCs) derived from hippocampus of neonatal rats.</p><p><b>METHODS</b>The classical method for 2x2 factorial analysis experiment was used to assess synergistic action of SCs and RA. NSCs were treated with RA, SCs, and SCs + RA in DMEM/F12 with 0.5% fetal bovine serum for six days, respectively. Double immunofluorescent staining was used to detect the differentiation of NSCs including nestin, glial fibrillary acidic protein (GFAP) and Map2. The expression of PSD95 was used to demonstrate synaptogenesis.</p><p><b>RESULTS</b>After NSCs were treated with RA or SCs, the expression of nestin and GFAP was significantly decreased while the expression of Map2 and PSD95 was significantly increased in comparison with the control. Factorial ANOVA showed that interactions between SCs and RA could induce the expression of Map2 and PSD95.</p><p><b>CONCLUSION</b>SCs and RA could promote synergistically the neuronal differentiation and synaptogenesis of hippocampal neural stem cells in vitro while they decreased the astrocytes and nestin positive NSCs.</p>