Search

BackgroundThe value of transplantation of BM stem cells in aged (12-month-old) mdx was evaluated because it is thought to be a more ideal model for studying the praxiology of Duchenne muscular dystrophy (DMD). The possible mechanisms of stem cell differentiation were then discussed.MethodsBM was isolated from 8–10-week-old male C57 BL/10 mice. After injecting BM cells into 12-month-old female mdx mice through the tail vein, the expression of dystrophin and MyoD was detected at different time points by immunofluorescence staining, RT-PCR and Western blot.ResultsThe C57 male mice donor-specific and Y-chromosome-specific sequence could be detected in all female aged mdx mice, implying the success of the transplantation. Expression of dystrophin and MyoD was detected and increased over time.DiscussionBM cells were recruited to the muscle and partially restored specific pathophysiologic features of the dystrophic muscle in aged mdx mice. Muscle differentiation of BM cells recapitulated embryonic myogenesis.

To investigate the differentiation of rat bone marrow mesenchymal stem cells (MSCs) into myocytes and their expression of dystrophin/utrophin after transplantation in mdx mice.BrdU-labeled fifth-passage rat MSCs were transplanted in mdx mice with previous total body gamma irradiation (7 Gy). At 4, 8, 12 and 16 weeks after the transplantation, the mice were sacrificed to detect dystrophin/BrdU and utrophin expressions in the gastrocnemius muscle using immunofluorescence assay, RT-PCR and Western blotting. Five normal C57 BL/6 mice and 5 mdx mice served as the positive and negative controls, respectively.Four weeks after MSC transplantation, less than 1% of the muscle fibers of the mdx mice expressed dystrophin, which increased to 15% at 16 weeks. Donor-derived nuclei were detected in both single and clusters of dystrophin-positive fibers. Some BrdU-positive nuclei were centrally located, and some peripherally within myofibers. Utrophin expression decreased over time after transplantation.The myofibers of mdx mice with MSC transplantation express dystrophin, which is derived partially from the transplanted MSCs. Dystrophin expression from the transplanted MSCs partially inhibits the upregulation of utrophin in mdx mouse muscle, showing a complementary relation between them.

To study the effects of BMP-2 and FGF-2 on osteoblast differentiation of murine MSCs in vitro.The bone marrow cells were collected from 3-18 month old C57BL/6J mice (50 mice), and they were isolated, enriched and expanded using bone marrow adherent culture, and then purified by immunomagnetic microbeads. At last they were identified as mesenchymal stem cells (MSCs). After the MSCs were cultured adherently for 24 hours, 100 microg/L BMP-2 and 0.5 nmol/L FGF-2 were added into osteogenic media separately for 7, 14 and 21 days, alkaline phosphatase (ALP) staining, alkaline phosphatase activities, Vonkossa staining, and Alizarin red S staining were performed step by step. Osteoblast differentiation marker genes including Runx2/cbfa1, ALP, collagen-1, and osteocalcin were investigated by RT real time PCR.ALP activities, calcium deposition and the osteoblast differentiation marker genes of BMP-2 group were markedly higher than those of osteogenic group. The mRNA of Runx2/cbfa1, ALP, collagen-1, and osteocalcin of BMP-2 group was highly expressed than that of osteogenic group. It was the same with FGF-2 group, but less evident than BMP-2 group.BMP-2 and FGF-2 can induce murine MSCs to differentiate into osteoblast at different degrees.

To investigate the dynamic distribution of human bone marrow mesenchymal stem cells (hBM-MSCs) in mdx mice.Twenty-four 8-10-week-old immunocompromised mdx mice were transplanted with 1 x 10(7) passage 5 hBM-MSCs labeled with bromodeoxyuridine (BrdU) by means of injection into the tail vein. The mice were euthanized 48 hours and 2, 4, 8, 12, 16, 20, and 24 weeks after transplantation. BrdU-positive cells in tissue and organs of the mice were detected by immunofluorescence analysis. Skeletal muscle was stained for anti-human nuclei mouse monoclonal antibody (anti-Hu) and analyzed for human dystrophin (Dys) expression by immunohistochemistry and reverse transcription-polymerase chain reaction.After transplantation, BrdU-positive cells were found in most organs (especially in bone marrow, liver, and lung) within 4 weeks, and these cells in liver and lung decreased gradually after 4 weeks. At 48 hours after transplantation, BrdU-positive cells were found in bone marrow, which reached a peak level after 2 weeks and were still detectable after 16 weeks. BrdU-positive cells in skeletal muscle increased gradually over time of transplantation. A small number of anti-Hu positive cells were detected in skeletal muscle 2 weeks after transplantation. A small number of Dys positive cell were seldom found at 4 weeks and small Dys mRNA expression detected 4 weeks after transplantation. The proportion of anti-Hu in parallel with Dys positive cells and Dys mRNA in skeletal muscle of mdx mice increased gradually over time of transplantation.After being transplanted into mdx mice, hBM-MSCs are mainly distributed in bone marrow, liver, and lung during the early time (2-4 weeks) , and then in bone marrow and skeletal muscle (after 4 weeks).

Amniotic fluid-derived stem cells have attracted considerable attention in the field of regenerative medicine. Approach of genetic modification probably enhances their regenerative potential. In this work, we wanted to determine whether baculovirus as a new gene vector could efficiently and safely transduce mouse amniotic fluid-derived stem cells (mAFSs). Cells were isolated from mouse amniotic fluid and cultured in vitro. These cells were analyzed by examining phenotypes and differentiation potential. They were further transduced with baculovirus. Baculovirus-transduced mAFSs were induced to differentiate into adipogenic, osteogenic, myogenic, and neurogenic lineages. Mouse amniotic fluid-derived stem cells were successfully isolated and cultured in vitro. They were positive for CD29 and Sca-1, but negative for CD34, CD45, or CD11b. Furthermore, they could differentiate into adipocytes, osteocytes, myocytes, and neurocytes in vitro. Baculovirus could efficiently transduced mAFSs. More importantly, baculovirus-transduced mAFSs retained differentiation potential. Thus, baculovirus vector effective and safe transduction is an attractive promise for genetic modification of mAFSs. Baculovirus genetically modified mAFSs will probably be more suitable as vehicles for regenerative medicine.

To investigate the effect on bone marrow stem cell transplantition (BMST) combinated with Bushen fang therapy in mdx mice.Cultured the bone marrow cells of C56BL/6 in vitro and tranplante these cells to mdx mice after irradiation. Bushen fang was used to cure the mdx mice after BMST. The survivel rate, symptom of Graft Versus Host Disease (GVHD) and motor function of model mice following irradiation and transplantation were observed 4 or 8 months after BMST, prepared the freeze-splice of muscles of each group, and made HE staining. The dystrophin (DYS) was detected by SABC immunofluorescene.Bushen fang could decrease the rate of centrally nucleated fibers (CNF), enhance expressional rate of DYS in different level and relieve the symptom of GVHD in transplanted mice.Bushen fang can improve the therapeutic efficacy of BMST.

To determine the effects of wild-type mouse bone marrow stem cells transplants on survival time and motor functions in the human mutant SOD1-G93A mouse model of familial amyotrophic lateral sclerosis (ALS).Bone marrow stem cells derived from the wild-type male mice were delivered intravenously into 25 ALS transgenic female mice (carrying the human SOD1 gene with Gly 93 Ala mutation) that had been pretreated with 5.5-6.5 Gy gamma-ray 5-7 days before. The onset time of limbs paralysis, lifespan and the graft versus host disease (GVHD) symptoms were observed in the treated group and statistically compared with control group of 15 media-injected ALS transgenic mice. The Sry gene (sex determine region on the Y chromosome) were detected by polymerase chain reaction technique in the blood sample of treated female ALS mice after 8 weeks of transplantation. A series of animal motor tests including rotating rods, rotated wheel and extension reflex were performed in both two groups at the same age of 16-17 weeks to assess the mice survival motor functions. Results A few treated mice (7/25) had different clinical presentations of GVHD. The semi-quantity evaluation score of average GVHD among the treated ALS mice was not over 1-2. The detection of Sry gene on these treated female ALS group was positive. The average onsets of limb paralysis and survival time were prolonged for about 5 weeks. At the age of 16-17 weeks, the motor function in the treated group was significantly better than in the ALS control group (P0.01).Transplantation of wild-type mice bone marrow stem cells can prolong survival in the recipient mice and ameliorate motor dysfunction. Intravenous administration of normal bone marrow stem cells may have therapeutic values for ALS.

To construct the retroviral vector containing human micro-dystrophin gene and detect the expression of human micro-dystrophin in mdx mice bone marrow-derived mesenchymal stem cells (MSCs) after retrovirus infection.Retroviral vector for micro-dystrophin gene was constructed and transferred into the packing cell PA317 mediated by Lipofectamine 2000. The retroviral supernatant containing the target genes were subsequently used to infect mdx mice MSCs. Micro-dystrophin expression was examined by methods of immunofluorescence staining and reverse transcriptase-polymerase chain reaction.Micro-dystrophin retroviral vector was successfully constructed and transferred into PA317 cells, and 48 h after infection with the recombinant retrovirus in mdx mice MSCs, 319 bp fragment could be detected by electrophoresis in the RT-PCR products. The red particles could be detected in some infected mdx mice MSCs with immunofluorescence staining. CONCLUSION mdx mice MSCs infected with retrovirus containing micro-dystrophin gene can express micro-dystrophin protein.

To investigate the dynamic changes of dystrophin expression in mdx mice after bone marrow stem cells transplantation.The bone marrow stem cells of C57 BL/6 mice (aged 6 to 8 weeks) were injected intravenously into the mdx mice (aged 7 to 9 weeks), which were preconditioned with 7Gy gamma ray. The amount of dystrophin;expression in gastrocnemius was detected by immunofluorescence, reverse transcription-polymerase chain reaction and Western blot at week 5, 8, 12 and 16 after transplantation.At week 5 after bone marrow stem cells transplantation, the dystrophin expression detected in mdx mice were very low; however, its expression increased along with time. At week 16 week, about 12% muscle cells of all transplanted mice expressed dystrophin. There were less centrally placed myonuclei than the control mdx mice, whereas peripheral myonuclei increased.After having been injected into mdx mice, the allogenic bone marrow stem cells have a trend to reach the injured muscle tissues and differentiate to fibers that can express dystrophin and the expression increased with time. The bone marrow stem cells participates in the repair and regeneration of the injured tissues permanently and constantly.

To establish transgenic mouse models of familial amyotrophic lateral sclerosis (FALS) and identify the genotype of the first filial generation.Six male B6SJL SOD1G93A/+ hemizygote mice were mated with 6 female B6SJLF1/J+/+ mice to produce the filial generation. The genomic DNA was extracted from the tail vein blood of the first filial generation mice and PCR was performed to amplify the hmSOD1 gene fragment. The genotype of the mice was determined by electrophoresis, and the PCR product was purified for further gene sequence analysis and detection of mutation loci.Fifty-three progeny mice were born and the survival rate before ALS onset was 98% (52/53), and among the survived mice, the positivity rate for hmSOD1 gene was 44.2% (23/52). Electrophoresis result showed that the PCR product of 236 bp was consistent with the hmSOD1 gene fragment, and the sequence of the PCR product was identical with hmSOD1 gene sequence of G93A mutant.Transgenic mouse models of ALS can be established in the first filial generation of male B6SJL SOD1G93A/+ mice mated with female B6SJLF1/J+/+. PCR technique can precisely identify the genotype of the filial generation.

To observe gene reversion during differentiation of human adult bone marrow-derived mesenchymal stem cells (MSCs) into neuron-like cells induced by Shenqiye.The MSCs were separated, cultured and expanded in the culture medium and induced to differentiate into neuron-like cells with Shenqiye. The expressions of neuron-specific enolase (NSE), neurofilament (NF), and glial fibrillary acidic protein (GFAP) were detected by immunocytochemical method, and the changes of 10 genes of the cells after differentiation were detected by reverse transcriptional PCR.The MSCs exhibited neuronal phenotype when treated with Shenqiye and the neuron-like cells were positive for expressions of NSE and NF but not for glial astrocyte marker GFAP. After withdrawal of Shenqiye from the medium, the neuron-like cells were reversed to MSC, flat or spindal in morphology. The gene expression profiles of the redifferentiated cells were similar to those of undifferentiated MSCs.Shenqiye can induce MSC differentiation into neuron-like cells during and after which gene reversion may occur.

To investigate the feasibility of using human bone marrow-derived mesenchymal stem cells (hBM- MSCs) for repairing the skeletal muscle sarcolemma lesions in mdx mice and characterize the distribution of the transplanted hBM-MSCs.Eighteen 8- to 10-week-old immunosuppressed mdx mice received transplantation with 1x10(7) of hBM-MSCs (the fifth passage) with 3H-thymidine (3H-TdR) labeling by injection of the cells into the tail vein. The mice were killed at 24 h, 48 h, 2 weeks, and 1, 2 and 4 months after the transplantation, respectively, to measure the radioactivity in the tissues and organs. Dystrophin expression on the sarcolemma was detected by immunofluorescence analysis.One month after transplantation, the mice with cell transplantation showed greater radioactivity in most of the tissues and organs than the control mice, especially in the bone marrow, liver and spleen. The radioactivity was then gradually lowered but in the skeletal muscle, the radioactivity increased progressively since 2 weeks after transplantation, reaching the peak of 27.65+/-3.53 Bq/mg at 1 month. Compared with that in the control mice, the radioactivity in the bone marrow and skeletal muscle was persistently higher in mice with cell transplantation 1 month after transplantation. No dystrophin-positive cells were found in the mdx mice at 2 weeks but detected at 1 month. The percentage of dystrophin-positive fibers in each section ranged from a 6.6% (1 month) to 8.9% (4 months).hBM-MSCs engrafted in immunosuppressed mdx mice may differentiate into skeletal muscle cells to repair the pathological lesion of the skeletal muscle sarcolemma. The hBM-MSCs reside mainly in the bone marrow, liver and spleen in the early stage following transplantation, homing into the bone marrow and skeletal muscle later.