Intravenous transplantation of bone marrow mesenchymal stem cells promotes neural regeneration after traumatic brain injury

To investigate the supplement of lost nerve cells in rats with traumatic brain injury by intravenous administration of allogenic bone marrow mesenchymal stem cells, this study established a Wistar rat model of traumatic brain injury by weight drop impact acceleration method and administered 3 × 106 rat bone marrow mesenchymal stem cells via the lateral tail vein. At 14 days after cell transplantation, bone marrow mesenchymal stem cells differentiated into neurons and astrocytes in injured rat cerebral cortex and rat neurological function was improved significantly. These findings suggest that intravenously administered bone marrow mesenchymal stem cells can promote nerve cell regeneration in injured cerebral cortex, which supplement the lost nerve cells.

Culture conditions for equine bone marrow mesenchymal stem cells and expression of key transcription factors during their differentiation into osteoblasts

Background： The use of equine bone marrow mesenchymal stem cells （BMSC） is a novel method to improve fracture healing in horses. However, additional research is needed to identify optimal culture conditions and to determine the mechanisms involved in regulating BMSC differentiation into osteoblasts. The objectives of the experiments were to determine： 1） if autologous or commercial serum is better for proliferation and differentiation of equine BMSC into osteoblasts, and 2） the expression of key transcription factors during the differentiation of equine BMSC into osteoblasts. Equine BMSC were isolated from the sterna of 3 horses, treated with purchased fetal bovine serum （FBS） or autologous horse serum （HS）, and cell proliferation determined. To induce osteoblast differentiation, cells were incubated with L-ascorbic acid-2-phosphate and glycerol-2-phosphate in the presence or absence of human bone morphogenetic protein2 （BMP2）, dexamethasone （DEX）, or combination of the two. Alkaline phosphatase （ALP） activity, a marker of osteoblast differentiation, was determined by ELISA. Total RNA was isolated from differentiating BMSC between d 0 to 18 to determine expression of runt-reloted tronscrJption foctor2 （Runx2）, osterix （Osx）, and T-box3 （Tbx3）. Data were analyzed by ANOVA. Results： Relative to control, FBS and HS increased cell number （133 ± 5 and 116 ± 5%, respectively; P 〈 0.001） and 5-bromo- 2＇-deoxyuridine （BrdU） incorporation （167 ± 6 and 120 ± 6%, respectively; P 〈 0.001）. Treatment with DEX increased ALP activity compared with control （1,638 ± 38%; P 〈 0.001）. In the absence and presence of Dex, BMP-2 did not alter ALP activity （P 〉 0.8）. Runt-reloted transcription foctor2 expression increased 3-fold （P 〈 0.001） by d 6 of culture. Osterix expression increased 94old （P 〈 0.05） by d 18 of culture. Expression of Tbx3 increased 1.8-fold at d 3 （P 〈 0.01）; however expression was reduced 4-fold at d 18 （P 〈 0.01）. Conclusions： Dexamethasone, but not BMP-2, is required for differentiation of equine BMSC into osteoblasts. In addition, expression of Runx2 and osterix increased and expression of Tbx3 is reduced during differentiation.

Dorsal root ganglion neurons promote proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells

Preliminary animal experiments have confirmed that sensory nerve fibers promote osteoblast differentiation, but motor nerve fibers have no promotion effect. Whether sensory neurons pro- mote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells remains unclear. No results at the cellular level have been reported. In this study, dorsal root ganglion neurons （sensory neurons） from Sprague-Dawley fetal rats were co-cultured with bone marrow mesenchymal stem cells transfected with green fluorescent protein 3 weeks after osteo- genic differentiation in vitro, while osteoblasts derived from bone marrow mesenchymal stem cells served as the control group. The rat dorsal root ganglion neurons promoted the prolifera- tion of bone marrow mesenchymal stem cell-derived osteoblasts at B and 5 days of co-culture, as observed by fluorescence microscopy. The levels of mRNAs for osteogenic differentiation-re- lated factors （including alkaline phosphatase, osteocalcin, osteopontin and bone morphogenetic protein 2） in the co-culture group were higher than those in the control group, as detected by real-time quantitative PCR. Our findings indicate that dorsal root ganglion neurons promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells, which pro- vides a theoretical basis for in vitro experiments aimed at constructing tissue-engineered bone.

The effect of neuropeptides on proliferation of rat bone marrow mesenchymal stem cells

Objective To investigate the effects and mechanism of calcitonin gene-related peptide(CGRP)and substance P (SP) on proliferation of rat bone marrow mesenchymal stem cells.Methods The rBMSCs were isolated using whole bone marrow

Improvement of neurological function in rats with spinal cord injury after the transplantation of neural stem cells directly differentiated from bone marrow mesenchymal stem cells

Objective To study the effect and mechanism of neurological function recovery in rats with spinal cord injury ( SCI) rats after transplantation of neural stem cells which are directly differentiated from bone marrow mesenchymal stem cells ( BMSC ) ,and to investigate the suitable engraftment time. Methods BMSC at 3rd passage were differentiated into neural stem cells ( NSC) , and immunofluorescence staining was used to

Cell multiplication, apoptosis and p-Akt protein expression of bone mesenchymal stem cells of rat under hypoxia environment

Objective ：To elucidate whether cell multiplication, apoptosis, glucose intake and p-Akt protein expression of bone Mesenchyreal Stem Cells（MSCs） of rats is influenced by a hypoxic environment ex vivo. Methods ：Passage 3 of bone marrow MSCs taken from Wistar rats,were cultured in a culturing chamber with 94%N2,1%O2,5%CO2 at 37℃. At different hypoxia time points ,0,0.5, 1,4 and 8 h, glucose uptake was assayed by using radiation isotope ^3H-G, Apoptotic Rate（AR） and dead rate（DR） were analyzed by flow cytometry（FCM） after Annexin V/PI staining, cell multiplication（by MTr methods） and p-Akt protein by immunocytochemistry and western blot. Results ：Assay for CD29^± ,CD44^± ,CD71^± ,CD34^-, Tn T^±（after 5-azacytidine agent inducing） and ALP^±（after bone differentiation agent inducing） suggested these bone-derived cells were MSCs. The ^3H-G intaking ratio （CPM/ flask value：157 ± 11,110 ± 11,107 ± 13,103 ± 10,100 ± 9 and 98 ± 10） of MSCs at different hypoxia time points, significantly decreased compared to that of normoxia（P 〈 0.01） and tended to descend slowly with hypoxia time duration, for which there was no statistical significance（P 〉 0.05）. The AR（0.09 ± 2.03%,12.9 ± 1.72%,13.7 ± 2.26%,13.8 ± 3.01%,14.1 ± 2.78% and 14.7 ± 4.01% at 0,0.5,1,4 and 8 h,respectively,P 〈 0.01） and DR （0.04, ± 1.79% ,0.93 ± 1.85% ,3.11 ± 2.14% ,4.09 ± 2.36% ,4.72 ± 2.05% and 4.91 ± 3.72% at 0,0.5,1,4 and 8 h, respectively, P 〈 0.05） at different hypoxia time points significantly increased compared to those time in normoxia; The AR further went up with time （P 〈 0.05）, however there was no statistical significance （P 〉 0.05） for the DR. Optical absorption value of MTr methods at different hypoxia time points significantly decreased compared to those with a corresponding normoxia time （P 〈 0.01） and degraded with time （in an hypoxic environment -P 〈 0.01）. IOD of p-Akt protein of MSCs at different hypoxia time points significantly increased （0.367 ± 0.031,0.556 ± 0.023,0.579 ± 0.013, 0.660 ± 0.024, 0.685 ± 0.039 and 0.685 ± 0.011, respectively） compared to their equivalents in normoxia （P〈0.05）, however, there was no statistical significance （P 〉 0.05） for different hypoxia time points. Hypoxia may result in ultramicrostructure changes, such as defluvium of Microvilli, apoptotic body, ＂margination＂ and so on and are further aggravated with hypoxia time stretching. Conclusion： Hypoxia may lead to a depression of MSCs intaldng glucose, creep of cell multiplication, upregulation of p-Akt protein and apoptosis of MSCs ex vivo.

Biological Characteristics of Human Bone Marrow Mesenchymal Stem Cell Cultured in Vitro

Some biological characteristics of human bone marrow mesenchymal stem cells (MSCs) cultured in vitro were observed. hMSCs were isolated from bone marrow and purified by density gradient centrifugation method, and then cultured in vitro. The proliferation and growth characteristics of hMSCs were observed in primary and passage culture. MSCs of passage 3 were examined for the purify by positive rate of CD29 and CD44 through flow cytometry. Human bone marrow MSCs showed active proliferation capacity in vitro. The purify of MSCs separated by our method was higher than 90 %. It was concluded that hMSCs have been successfully cultured and expanded effectively. It provided a foundation for further investigation and application of MSCs.

Gender difference in the neuroprotective effect of rat bone marrow mesenchymal cells against hypoxiainduced apoptosis of retinal ganglion cells

Bone marrow mesenchymal stem cells can reduce retinal ganglion cell death and effectively prevent vision loss. Previously, we found that during differentiation, female rhesus monkey bone marrow mesenchymal stem cells acquire a higher neurogenic potential compared with male rhesus monkey bone marrow mesenchymal stem cells. This suggests that female bone marrow mesenchymal stem cells have a stronger neuroprotective effect than male bone marrow mesenchymal stem cells. Here, we first isolated and cultured bone marrow mesenchymal stem cells from female and male rats by density gradient centrifugation. Retinal tissue from newborn rats was prepared by enzymatic digestion to obtain primary retinal ganglion cells. Using the transwell system, retinal ganglion cells were co-cultured with bone marrow mesenchymal stem cells under hypoxia. Cell apoptosis was detected by flow cytometry and caspase-3 activity assay. We found a marked increase in apoptotic rate and caspase-3 activity of retinal ganglion cells after 24 hours of hypoxia compared with normoxia. Moreover, apoptotic rate and caspase-3 activity of retinal ganglion cells significantly decreased with both female and male bone marrow mesenchymal stem cell co-culture under hypoxia compared with culture alone, with more significant effects from female bone marrow mesenchymal stem cells. Our results indicate that bone marrow mesenchymal stem cells exert a neuroprotective effect against hypoxia-induced apoptosis of retinal ganglion cells, and also that female cells have greater neuroprotective ability compared with male cells.

Osteogenic Differentiation of Bone Mesenchymal Stem Cells Regulated by Osteoblasts under EMF Exposure in a Co-culture System

This study examined the osteogenic effect of electromagnetic fields （EMF） under the simulated in vivo conditions. Rat bone marrow mesenchymal stem cells （BMSCs） and rat osteoblasts were co-cultured and exposed to 50 Hz, 1.0 mT EMF for different terms. Unexposed single-cultured BMSCs and osteoblasts were set as controls. Cell proliferation features of single-cultured BMSCs and osteoblasts were studied by using a cell counting kit （CCK-8）. For the co-culture system, cells in each group were randomly chosen for alkaline phosphatase （ALP） staining on the day 7. When EMF exposure lasted for 14 days, dishes in each group were randomly chosen for total RNA extraction and von Kossa staining. The mRNA expression of osteogenic markers was detected by using real-time PCR. Our study showed that short-term EMF exposure （2 h/day） could obviously promote prolifera- tion of BMSCs and osteoblasts, while long-term EMF （8 h/day） could promote osteogenic differen- tiation significantly under co-cultured conditions. Under EMF exposure, osteogenesis-related mRNA expression changed obviously in co-cultured and single-cultured cells. It was noteworthy that most osteogenic indices in osteoblasts were increased markedly after co-culture except Bmp2, which was increased gradually when ceils were exposed to EMF. Compared to other indices, the expression of Bmp2 in BMSCs was increased sharply in both single-cultured and co-cultured groups when they were exposed to EMF. The mRNA expression of Bmp2 in BMSCs was approximately four times higher in 8-h EMF group than that in the unexposed group. Our results suggest that Bmp2-mediated cellular interaction induced by EMF exposure might play an important role in the osteogenic differ- entiation of BMSCs.

Therapeutic Potential of Bone Marrow Derived Mesenchymal Stem Cells in Modulating Astroglyosis of Surgical Induced Experimental Spinal Cord Injury

Background: Spinal cord injury (SCI) unsuccessful regeneration was due to glial scar development. It was a major obstacle to axonal restoration. Safe therapeutic intervention by the use of bone marrow derived stem cells (BMMSCs) transplantation applied in the present study could reduce spinal disability. Material and methods: Forty male albino rats were divided into four groups: GI: negative control (n = 10 rats);GII: positive control after SCI (n = 10 rats);GIII: SCI + BM - MSCs intravenous injected and GIV: SCI + BM - MSCs intra lesion injected (n = 10 rats in each group). The samples were taken from spinal cord tissues around the region of injury and were subjected to histological, immunohistochemical assessment. RNA extraction and real time PCR for detection of nerve regeneration and astrocyte response to the injury were also performed. Results: Clinical improvement occurred by the enhancement in the Basso, Beattie and Bresnahan (BBB) score after SCI. Histological examinations showed positive regenerative responses in GIV compared to GIII. Conclusion: BM-MSCs transplantation has a promising role in enhancing the microenvironment for nerve regeneration through stumbling the glial scaring formation and inflammatory response after chronic spinal cord injury especially by using intra-lesion route injection.

Effect of SHU555A labeling on differentiation of bone marrow mesenchymal stem cells into neurocyte-like cells

Objective:To investigate the effect of SHU555A,a clinically approved iron nanoparticle,labeling on differentiation of bone marrow mesenchymal stem cells(BMSCs) into neurocyte-like cells in vitro.Methods:10 times dilution of 10μl,20μl,40μl and 80μl SHU555A were added to 2ml of culture medium containing rat BMSCs to obtain four experimental groups of SHU555A labeling of BMSCs with ferri ion concentrations of 14μg/ml,28μg/ml,56μg/ml and 112μg/ml,respectively.2ml of culture medium with rat BMSCs did not contain SHU555A served as control group.The BMSCs of all the groups were pre-induced by bFGF,and induced by DMSO/butylated hydroxyanisole(BHA) for six hours,subsequently reverse transcription polymerase chain reaction(RT-PCR) technique was employed to detect mRNA expression of nestin,neuronspecific analase(NSE) and glial fibrillary acid protein(GFAP).Western blot technique was used to detectprotein expression of nestin.Results:Quantitative-PCR revealed high mRNA expression of nestin,NSE and GFAP induced by DMSO/BHA in all the experimental groups,but the difference between the experimental groups and the control group was not significant(P>0.05).Western blot analysis demonstrated there was no statistically significant difference in nestin protein expression between the experimental groups and the control group(P>0.05).Conclusion:SHU555A labeling do not affect differentiation of rat BMSCs into neurocyte-like cells in vitro.

The effect of bone marrow mesenchymal stem cell transplantation on hypoxic pulmonary hypertension in rats

Objective:To study the influence of bone marrow mesenchymal stem cells(MSCs)transplantation on hypoxic pulmonary hypertension(HPH)in rats.Methods:MSCs in SD rats were separated,cultivated,identified in vitro,and labeled by the green fluorescence protein(GFP)adenovirus.Healthy male SD rats were randomly divided into four groups:normal control group(NC group)and HPH group,with eight rats in each group respectively;HPH+mesenchymal stem cell transplantation group(MSCs group)and HPH+vascular endothelial growth factor+mesenchymal stem cell transplantation group(VEGF+MSCs group),with twenty-four rats in each group respectively.In this experiment,intermittent normobaric hypoxia was employed to establish the pulmonary hypertension rat models,with stem cells transfected and transplanted.The mean pulmonary artery pressure(mPAP)was observed in rats to calculate the right ventricular hypertrophy index(RVHI);the morphological changes of pulmonary arterioles in each group of rats were observed under the microscope;the distribution and manifestation of MSCs fluorescently labeled by adenovirus transfection were observed in pulmonary arterioles under the fluorescence microscope at the set time points of 7 d,14 d and 28 d after the transplantation of stem cells.Results:For NC group,the mPAP(mmHg)was 15.5±1.5 at 28 d,while the mPAP in HPH,MSCs and VEGF+MSCs groups were 26.1±1.9,21.6±2.7 and 20.1±2.9 respectively which were apparently higher than that in NC group(p<.01).Compared with HPH group(p<.01),the mPAP was obviously decreased in MSCs and VEGF+MSCs groups.There was no significant difference between MSCs and VEGF+MSCs groups.At 28 d,RVHI for NC group was 0.28±0.02,while the RVHI in HPH,MSCs and VEGF+MSCs groups were 0.43±0.07,0.34±0.03 and 0.35±0.01 respectively which were apparently higher than that in NC group(p<.01).In comparison with HPH group,RVHI was significantly decreased in MSCs and VEGF+MSCs groups(p<.05).There was no significant difference between MSCs and VEGF+MSCs groups.For HPH group,at 28 d,pulmonary arterioles were apparently thickened,with luminal stenosis&obliteration and incomplete endothelial cells.Compared with HPH group,pulmonary arterioles in MSCs group became thinning,with the lumen unobstructed and the integrity of endothelial cells improved.The changes in the manifestation of MSCs and VEGF+MSCs groups were not significant.Conclusions:The transplantation of MSCs can improve the remodeling of pulmonary arterioles to partially reverse the progress of HPH;the combined transplantation of VEGF and MSCs doesn’t improve the effect of MSC transplantation.

Conditions to improve expansion of human mesenchymal stem cells based on rat samples

AIM: To improve the isolation and expansion of human marrow-derived mesenchymal stem cells (MSCs) based on rat samples. METHODS: Based on the fact that rat MSCs are relatively easy to obtain from a small aspirate, bone marrow-derived MSCs from rat were cultured and characterized to set up the different protocols used in this study. Then, accordingly, almost the same protocols were performed on human healthy bone marrow samples, after obtaining approval of the ethics committee and gaining informed consent. We used different protocols and culture conditions, including the type of basal media and the culture composition. The MSCs were characterized by immunophenotyping and differentiation. RESULTS: There was no difference in morphology and proliferation capacity between different culture media at the first passage. During the 5-7th passages, the cells gradually lost their morphology and proliferation potential on Dulbecco’s modified Eagle’s medium (DMEM) high glucose and α modified Eagle’s medium. Although the cells expanded rapidly for up to 10 passages on DMEM low glucose containing 10% to 15% fetal calf serum (FCS), their proliferation was arrested without change in morphology and differentiation capacity at the third passage on 5% FCS. Flow cytometric analysis and functional tests confirmed that more than 90% of marrow cells which were isolated and expanded by our selective protocols were MSCs. CONCLUSION: We improved the isolation and expansion of human bone marrow derived MSCs, based on rat sample experiments, for further experimental and clinical use.

In vitro chondrogenesis of the goat bone marrow mesenchymal stem cells directed by chondrocytes in monolayer and 3-dimetional indirect co-culture system

Background Cartilage injury has a very poor capacity for intrinsic regeneration. The cell-based treatment strategy for the cartilage repair using differentiated bone marrow mesenchymal stem cells （BMSCs） is, however, a promising approach to the chondral repair. This study was aimed to explore the chondrogenic potential of the goat BMSCs in the Transwell co-culture system and the poly-laetide-co-glycolide （PLGA） scaffolds.Methods The BMSCs were isolated from the goat iliac crest while the chondrocytes were obtained from the goat＇s last costal cartilage. In the Transwell co-culture system, the BMSCs co-cultured with chondrocytes were designed as group A,whereas the goat＇s BMSCs induced with the chondrogenic medium were group B. Both groups A and B were the experimental groups, while group C that only contained BMSCs was the control group. In the PLGA scaffolds co-culture system, BMSCs were seeded into the PLGA scaffolds, which were suspended in the 24-well plate, and the control group was established by presence or absence of chondrocytes at the bottom of the 24-well plate. Toluidine blue staining,Alcian blue staining, collagen Ⅱ immunofluoresence, collagen Ⅱ immunochemical staining, collagen Ⅰ, collagen Ⅱ, COL2a Q-PCR and osteopontin Q-PCR were used to examine the chondrogenic conditions as well as the expressions of chondrogenic and osteogenic genes.Results Cells isolated from the aspirates of the goat bone marrow proliferated rapidly and gained characteristics of stem cells in Passage 4. However, the differentiations of chondrocytes were not apparent in Passage 3. The results from Toluidine blue staining, collagen Ⅱ immunofluoresence and PCR showed the transformation of BMSCs to chondrocytes in the Transwell co-culture system and PLGA scaffolds. Although the cartilage gene expressions were upgraded in both chondrogenesis group and co-culture system, the osteopontin gene expression, which represents osteogenic level, was also up-regulated.Conclusions The Transwell co-culture system and the PLGA scaffolds co-culture system can promote the chondrogenic differentiation of the goat＇s BMSCs, while up-regulated osteopontin gene expression in the Transwell co-culture system implies the osteogenic potential of BMSCs.

Development of bone marrow mesenchymal stem cell culture in vitro

Objective To review the in vitro development of bone marrow mesenchymal stem cells culture （BM-MSC）.Data sources The data cited in this review were mainly obtained from articles listed in Medline and PubMed. The search terms were “bone marrow mesenchymal stem cell” and “cell culture”.Study selection Articles regarding the in vitro development of BM-MSCs culture, as well as the challenge of optimizing cell culture environment in two-dimensional （2D） vs. 3D.Results Improving the culture conditions increases the proliferation and reduces the differentiation. Optimal values for many culture parameters remain to be identified. Expansion of BM-MSCs under defined conditions remains challenging, including the development of optimal culture conditions for BMSC and large-volume production systems.Conclusions Expansion of BM-MSCs under defined conditions remains challenges, including the development of optimal culture conditions for BMSC and scale-up to large-volume production systems. Optimal values for many culture parameters remain to be identified.

淫羊藿苷含药血清促进3种细胞共培养体系中软骨细胞增殖和干细胞成软骨分化

背景:关节软骨损伤修复能力十分有限,组织工程技术为修复受损软骨提供了新的治疗方案,其中软骨细胞、骨髓间充质干细胞和滑膜间充质干细胞之间的相互影响和诱导作用是自体软骨损伤愈合的基础。目的:构建软骨细胞-骨髓间充质干细胞-滑膜间充质干细胞共培养体系用以模拟软骨细胞体内微环境,并探究其最佳细胞接种比例,同时观察淫羊藿苷含药血清对该体系中软骨细胞增殖和干细胞成软骨分化的影响。方法:提取、培养、鉴定大鼠膝关节软骨细胞、骨髓间充质干细胞和滑膜间充质干细胞,按不同细胞接种比例构建软骨细胞-骨髓间充质干细胞-滑膜间充质干细胞非接触共培养体系,共培养72 h后观察软骨细胞增殖活性和表型能力,选择综合效应最佳的共培养体系;用淫羊藿苷溶液(0.25 mg/m L)灌胃新西兰大白兔制备淫羊藿苷含药血清,对照组共培养体系用含体积分数为10%胎牛血清、1%双抗的高糖DMEM培养液培养,实验组共培养体系在此基础之上加入体积分数为10%淫羊藿苷含药血清进行干预,24,48 h后检测两组软骨细胞增殖活性和Ⅱ型胶原表达,14 d后采用免疫荧光染色检测骨髓间充质干细胞、滑膜间充质干细胞成软骨分化情况。结果与结论:(1)3种细胞以不同比例共培养时均可正常贴壁生长,当软骨细胞、骨髓间充质干细胞、滑膜间充质干细胞接种比例为2∶1∶1时,共培养体系中软骨细胞表现出最佳增殖活性和表型能力;(2)与对照组相比,实验组培养24 h后软骨细胞增殖活性和Ⅱ型胶原表达显著升高(P<0.01),48 h后两组仍有差异(P<0.05),培养14 d后两组骨髓间充质干细胞和滑膜间充质干细胞出现明显的软骨分化,部分细胞呈现圆形或椭圆形,胞浆Ⅱ型胶原免疫荧光染色为阳性,实验组荧光强度明显高于对照组(P<0.01);(3)结果表明,以非接触共培养方法可以成功建立软骨细胞-骨髓间充质干细胞-滑膜间充质干细胞共培养体系且细胞比例为2∶1∶1时软骨细胞增殖活性和表型能力最佳;同时淫羊藿苷含药血清具有促进该体系中软骨细胞增殖及骨髓间充质干细胞、滑膜间充质干细胞成软骨分化的作用。

Human adipose-derived mesenchymal stem cells： a better cell source for nervous system regeneration

Background In order to suggest an ideal source of adult stem cells for the treatment of nervous system diseases,MSCs from human adipose tissue and bone marrow were isolated and studied to explore the differences with regard to cell morphology,surface markers,neuronal differentiation capacity,especially the synapse structure formation and the secretion of neurotrophic factors.Methods The neuronal differentiation capacity of human mesenchymal stem cells from adipose tissue （hADSCs） and bone marrow （hBMSCs） was determined based on nissl body and synapse structure formation,and neural factor secretion function.hADSCs and hBMSCs were isolated and differentiated into neuron-like cells with rat brain-conditioned medium,a potentially rich source of neuronal differentiation promoting signals.Specific neuronal proteins and neural factors were detected by immunohistochemistry and enzyme-linked immunosorbent assay analysis,respectively.Results Flow cytometric analysis showed that both cell types had similar phenotypes.Cell growth curves showed that hADSCs proliferated more quickly than hBMSCs.Both kinds of cells were capable of osteogenic and adipogenic differentiation.The morphology of hADSCs and hBMSCs changed during neuronal differentiation and displayed neuronlike cell appearance after 14 days＇ differentiation.Both hADSCs and hBMSCs were able to differentiate into neuron-like cells based on their production of neuron specific proteins including β-tubulin-Ⅲ,neuron-specific enolase （NSE）,nissl bodies,and their ability to secrete brain derived neurotrophic factor （BDNF） and nerve growth factor （NGF）.Assessment of synaptop hysin and growth-associated protein-43 （GAP-43） suggested synapse structure formation in differentiated hADSCs and hBMSCs.Conclusions Our results demonstrate that hADSCs have neuronal differentiation potential similar to hBMSC,but with a higher proliferation capacity than hBMSC.Adipose tissue is abundant,easily available and would be a potential ideal source of adult stem cells for neural-related clinical research and application.

Transplantation of Nogo-66 receptor gene-silenced cells in a poly(D,L-lactic-co-glycolic acid) scaffold for the treatment of spinal cord injury

Inhibition of neurite growth, which is in large part mediated by the Nogo-66 receptor, affects neural regeneration following bone marrow mesenchymal stem cell transplantation. The tissue engineering scaffold poly（D,L-lactide-co-glycolic acid） has good histocompatibility and can promote the growth of regenerating nerve fibers. The present study used small interfering RNA to silence Nogo-66 receptor gene expression in bone marrow mesenchymal stem cells and Schwann cells, which were subsequently transplanted with poly（D,L-lactide-co-glycolic acid） into the spinal cord lesion regions in rats. Simultaneously, rats treated with scaffold only were taken as the control group. Hematoxylin-eosin staining and immunohistochemistry revealed that at 4 weeks after transplantation, rats had good motor function of the hind limb after treatment with Nogo-66 receptor gene-silenced ceils prus the poly（O,L-lactide-co-glycolic acid） scaffold compared with rats treated with scaffold only, and the number of bone marrow mesenchymal stem cells and neuron-like cells was also increased. At 8 weeks after transplantation, horseradish peroxidase tracing and transmission electron microscopy showed a large number of unmyelinated and myelinated nerve fibers, as well as intact regenerating axonal myelin sheath following spinal cord hemisection injury. These experimental findings indicate that transplantation of Nogo-66 receptor gene-silenced bone marrow mesenchymal stem cells and Schwann cells plus a poly（D,L-lactide-co-glycolic acid） scaffold can significantly enhance axonal regeneration of spinal cord neurons and improve motor function of the extremities in rats following spinal cord injury.

Dynamic culture of a thermosensitive collagen hydrogel as an extracellular matrix improves the construction of tissue-engineered peripheral nerve

Tissue engineering technologies offer new treatment strategies for the repair of peripheral nerve injury, hut cell loss between seeding and adhesion to the scaffold remains inevitable. A thermosensitive collagen hydrogel was used as an extracellular matrix in this study and combined with bone marrow mesenchymal stem cells to construct tissue-engineered peripheral nerve composites in vitro. Dynamic culture was performed at an oscillating frequency of 0.5 Hz and 35° swing angle above and below the horizontal plane. The results demonstrated that bone marrow mesenchymal stem cells formed membrane-like structures around the poly-L-lactic acid scaffolds and exhibited regular alignment on the composite surface. Collagen was used to fill in the pores, and seeded cells adhered onto the poly-L-lactic acid fibers. The DNA content of the bone marrow mesenchymal stem cells was higher in the composites constructed with a thermosensitive collagen hydrogel compared with that in collagen I scaffold controls. The cellular DNA content was also higher in the thermosensitive collagen hydrogel composites constructed with the thermosensitive collagen hydrogel in dynamic culture than that in static culture. These results indicate that tissue-engineered composites formed with thermosensitive collagen hydrogel in dynamic culture can maintain larger numbers of seeded cells by avoiding cell loss during the initial adhe-sion stage. Moreover, seeded cells were distributed throughout the material.

Differentiation of marrow-derived islet-like cells and their effects on diabetic rats

In recent years, islet transplantation for diabetes has shown signs of the treatment efficacy, but its application is limited due to lack of donor organizations, sources and immune rejection. Bone marrow mesenchymal stem cells （BMSCs） have become a new resource of islet cell substitutes. One focus of the current research is the application of a specific inducing agent or a culture system to get directed differentiation of BMSCs, which may have part characteristics of islet cells and then be used in autologous transplantation for the treatment of diabetes.