骨髓间质干细胞向大鼠损伤心肌组织的迁移

实验旨在动态观察骨髓间充质干细胞（mesenchymal stem cells,MSCs）向不同微环境下心肌组织的迁移特点,明确组织损伤在干细胞迁移中的作用,为提高干细胞治疗的靶向性和高效性奠定初步试验基础。分离纯化雄性Sprague-Dawley（SD）大鼠的骨髓MSCs,输注入雌性SD大鼠。实验分为4组：正常大鼠＋MSCs移植组,假手术＋MSCs移植组,心肌缺血＋MSCs移植组,心肌缺血对照组（心肌缺血＋培养基移植）。结扎冠状动脉前降支制造心肌缺血模型,将相等数量的雄性MSCs经尾静脉注射移植入前3组雌性大鼠体内,对照组注射等体积培养基,分别于移植后1周及8周取心脏组织标本,采用荧光原位杂交方法（fluorescence in situ hybridization,FISH）检测大鼠Y染色体雄性鉴别基因sty片段的表达,用透射电镜观察大鼠心肌组织超微结构改变。结果发现,移植后1周和8周,正常大鼠移植组和对照组大鼠的心肌组织中均未见sry基因的表达,但假手术移植组和心肌缺血移植组的心肌组织中均可见sty基因的表达,心肌缺血移植组的Y染色体sty基因阳性细胞数量在两个时间点均显著高于假手术移植组（P〈0．01）。分别比较心肌缺血移植组和假手术组在移植后1周和8周的Y染色体sry基因阳性细胞的数量,两个时间点无明显差异。心肌组织的超微结构观察发现心肌缺血移植组大鼠的心肌梗死周边区域可见一些细胞,其形态类似于体外培养的MSCs。研究结果提示MSCs具有向损伤心肌组织迁移的特性,迁移的高峰期可能在组织损伤1周左右,组织损伤及其程度在干细胞迁移中起重要作用。     

Neuromuscular Electrical Stimulation as a Method to Maximize the Beneficial Effects of Muscle Stem Cells Transplanted into Dystrophic Skeletal Muscle

Cellular therapy is a potential approach to improve the regenerative capacity of damaged or diseased skeletal muscle. However, its clinical use has often been limited by impaired donor cell survival, proliferation and differentiation following transplantation. Additionally, functional improvements after transplantation are all-too-often negligible. Because the host microenvironment plays an important role in the fate of transplanted cells, methods to modulate the microenvironment and guide donor cell behavior are warranted. The purpose of this study was to investigate whether the use of neuromuscular electrical stimulation (NMES) for 1 or 4 weeks following muscle-derived stem cell (MDSC) transplantation into dystrophic skeletal muscle can modulate the fate of donor cells and enhance their contribution to muscle regeneration and functional improvements. Animals submitted to 4 weeks of NMES after transplantation demonstrated a 2-fold increase in the number of dystrophin+ myofibers as compared to control transplanted muscles. These findings were concomitant with an increased vascularity in the MDSC+NMES group when compared to non-stimulated counterparts. Additionally, animals subjected to NMES (with or without MDSC transplantation) presented an increased maximal specific tetanic force when compared to controls. Although cell transplantation and/or the use of NMES resulted in no changes in fatigue resistance, the combination of both MDSC transplantation and NMES resulted in a faster recovery from fatigue, when compared to non-injected and non-stimulated counterparts. We conclude that NMES is a viable method to improve MDSC engraftment, enhance dystrophic muscle strength, and, in combination with MDSC transplantation, improve recovery from fatigue. These findings suggest that NMES may be a clinically-relevant adjunct approach for cell transplantation into skeletal muscle.     

Transplanted embryonic stem cells survive, differentiate and promote recovery in injured rat spinal cord

Transplantation approaches using cellular bridges, fetal central nervous system cells, fibroblasts expressing neurotrophin-3 (ref. 6), hybridoma cells expressing inhibitory protein-blocking antibodies, or olfactory nerves ensheathing glial cells transplanted into the acutely injured spinal cord have produced axonal regrowth or functional benefits. Transplants of rat or cat fetal spinal cord tissue into the chronically injured cord survive and integrate with the host cord, and may be associated with some functional improvements. In addition, rats transplanted with fetal spinal cord cells have shown improvements in some gait parameters, and the delayed transplantation of fetal raphe cells can enhance reflexes. We transplanted neural differentiated mouse embryonic stem cells into a rat spinal cord 9 days after traumatic injury. Histological analysis 2-5 weeks later showed that transplant-derived cells survived and differentiated into astrocytes, oligodendrocytes and neurons, and migrated as far as 8 mm away from the lesion edge. Furthermore, gait analysis demonstrated that transplanted rats showed hindlimb weight support and partial hindlimb coordination not found in 'sham-operated' controls or control rats transplanted with adult mouse neocortical cells.     

Rapid Lymphocyte Reconstitution of Unconditioned Immunodeficient Mice with Non-Self-Renewing Multipotent Hematopoietic Progenitors

The replacement of abnormal hematopoietic stem cells (HSCs) with normal transplanted HSCs can correct a wide range of hematologic disorders. Here, we provide evidence that transplantation of more differentiated progenitor cells can be used to more rapidly correct lymphoid deficiencies in unconditioned immunocompromised mice. Transplantation of flk2+ multipotent progenitors led to robust B and T cell reconstitution that was maintained for at least 16 weeks. Antigenic challenge at 16 weeks post-transplantation revealed that reconstituted lymphocytes maintained a functional repertoire. In contrast to the persistent lymphocytic engraftment, myeloid chimerism was lost by 12 weeks post-transplantation consistent with the fact that flk2+ progenitors are non-self-renewing. Thus, while more differentiated progenitors are capable of rescuing lymphoid deficiencies, transplantation of HSCs must be used for the correction of non-lymphoid disorders, and, we propose, very long-term immune reconstitution. Based on recent evidence, we discuss novel strategies to achieve the replacement of abnormal HSCs without the use of cytotoxic conditioning regimens.     

Umbilical Cord Blood Stem Cell Mediated Downregulation of Fas Improves Functional Recovery of Rats after Spinal Cord Injury

Human umbilical cord blood stem cells (hUCB), due to their primitive nature and ability to develop into nonhematopoietic cells of various tissue lineages, represent a potentially useful source for cell-based therapies after spinal cord injury (SCI). To evaluate their therapeutic potential, hUCB were stereotactically transplanted into the injury epicenter, one week after SCI in rats. Our results show the presence of a substantial number of surviving hUCB in the injured spinal cord up to five weeks after transplantation. Three weeks after SCI, apoptotic cells were found especially in the dorsal white matter and gray matter, which are positive for both neuron and oligodendrocyte markers. Expression of Fas on both neurons and oligodendrocytes was efficiently downregulated by hUCB. This ultimately resulted in downregulation of caspase-3 extrinsic pathway proteins involving increased expression of FLIP, XIAP and inhibition of PARP cleavage. In hUCB-treated rats, the PI3K/Akt pathway was also involved in antiapoptotic actions. Further, structural integrity of the cytoskeletal proteins α-tubulin, MAP2A&2B and NF-200 has been preserved in hUCB treatments. The behavioral scores of hind limbs of hUCB-treated rats improved significantly than those of the injured group, showing functional recovery. Taken together, our results indicate that hUCB-mediated downregulation of Fas and caspases leads to functional recovery of hind limbs of rats after SCI.     

Oligoprogenitor Cells Derived from Spermatogonia Stem Cells Improve Remyelination in Demyelination Model

Embryonic stem (ES) like cells-derived testis represents a possible alternative to replace of neurons and glia. Here, we differentiated spermatogonia cells to oligoprogenitor (OP) like cells and transplanted them to demyelination model and assess their recovery potential in a demyelinated corpus callosum model in rats. ES like cells were differentiated to OP like cells using appropriate inducers and were transplanted in situ to demyelinated corpus callosum. Cell integration as well as demyelination extension and myelination intensity changes were evaluated using histologic studies and immunocytochemistry after 2 and 4 weeks post transplantation. Investigation of Nestin, NF68, Olig2, and NG2 by immunocytochemical technique indicated the differentiation of ES like cells to neuroprogenitor and oligodendrocyte like cells in each induction stage. Histologic findings showed a significant decrease in demyelination extension and a significant increase in remyelination intensity in cell transplanted groups. Also on the base of PLP expression, differentiation of transplanted cells was confirmed to myelinogenic cells using immunocytochemistry technique. We conclude that ES like cells derived from spermatogonia cells can be differentiated to OP like cells that can form myelin after transplantation into the demyelination model in rat, this represents recovery potential of spermatogonia cells which opens new window for cell therapeutic approaches using spermatogonial stem cells.     

Intracoronary artery transplantation of cardiomyoblast-like cells from human adipose tissue-derived multi-lineage progenitor cells improve left ventricular dysfunction and survival in a swine model of chronic myocardial infarction

Transplantation of human cardiomyoblast-like cells (hCLCs) from human adipose tissue-derived multi-lineage progenitor cells improved left ventricular function and survival of rats with myocardial infarction. Here we examined the effect of intracoronary artery transplantation of human CLCs in a swine model of chronic heart failure. Twenty-four pigs underwent balloon-occlusion of the first diagonal branch followed by reperfusion, with a second balloon-occlusion of the left ascending coronary artery 1week later followed by reperfusion. Four weeks after the second occlusion/reperfusion, 17 of the 18 surviving animals with severe chronic MI (ejection fraction <35% by echocardiography) were immunosuppressed then randomly assigned to receive either intracoronary artery transplantation of hCLCs hADMPCs or placebo lactic Ringer's solution with heparin. Intracoronary artery transplantation was followed by the distribution of DiI-stained hCLCs into the scarred myocardial milieu. Echocardiography at post-transplant days 4 and 8weeks showed rescue and maintenance of cardiac function in the hCLCs transplanted group, but not in the control animals, indicating myocardial functional recovery by hCLCs intracoronary transplantation. At 8week post-transplantation, 7 of 8 hCLCs transplanted animals were still alive compared with only 1 of the 5 control (p=0.0147). Histological studies at week 12 post-transplantation demonstrated engraftment of the pre DiI-stained hCLCs into the scarred myocardium and their expression of human specific alpha-cardiac actin. Human alpha cardiac actin-positive cells also expressed cardiac nuclear factors; nkx2.5 and GATA-4. Our results suggest that intracoronary artery transplantation of hCLCs is a potentially effective therapeutic strategy for future cardiac tissue regeneration.     

骨髓间充质干细胞黑质内移植对帕金森病大鼠的治疗作用

目的探索骨髓间充质干细胞（BMSCs）移植到帕金森病（Parkinson’s disease,PD）大鼠毁损侧黑质内,PD模型大鼠的姿势不对称性和黑质及纹状体内酪氨酸羟化酶（tyrosinehy droxylase,TH）表达的改变,以及BM—SCs在大鼠脑内的存活、分化情况。方法黑质、前脑内侧束两点法注射6一羟多巴胺（6-OHDH）并行为学分析筛选PD模型大鼠。将PD模型大鼠随机分为移植组和对照组。BMSCs移植术后4周和8周,观察大鼠姿势不对称性,免疫组织化学及免疫荧光显色方法检测黑质和纹状体酪氨酸羟化酶（tyrosine hydroxylase,TH）的表达变化以及BMSCs在大鼠体内的存活、迁移及分化情况。结果BMSCs黑质内移植可使PD模型大鼠的转动频率由（10．62±2．97）r／min降至（4．65±1．08）r／min（P〈0．01）,显著增加毁损侧黑质TH阳性细胞数量和纹状体内TH阳性纤维密度。BMSCs在大鼠黑质内可以存活至少8周,部分细胞分化为神经干细胞、神经元和神经胶质细胞。结论黑质内移植BMSCs对PD模型大鼠有一定的治疗作用。     

人羊膜上皮细胞移植及基因治疗帕金森病大鼠

观察人羊膜上皮细胞(human amniotic epithelial cell,HAEC及)人脑源性神经营养因子(brain-derived neurotrophic factor,BDNF基)因修饰的HAEC在帕金森病(Parkinson’sdisease,PD)模型大鼠脑内的长期存活和对旋转行为的治疗效果。用包装BDNFcDNA的慢病毒转染原代HAEC(HAEC/BDNF),HAEC/BDNF与HAEC分别植入6-羟基多巴胺损伤的PD模型大鼠纹状体内,观察动物的旋转行为,用免疫组织化学方法鉴定移植物在体内的存活。结果表明,治疗组PD大鼠的旋转行为改善明显达14周,HAEC/BDNF组能使恢复时间提前。免疫组织化学方法发现移植细胞在14周后仍有少量存活且部分表达BDNF、酪氨酸羟化酶,纹状体内星形胶质细胞增生。实验结果说明,HAEC和BDNF基因修饰的HAEC移植对PD模型大鼠的行为有一定改善,HAEC可以作为一种治疗PD的供体细胞。     

Behavior of transplanted bone marrow-derived GFP mesenchymal cells in osteochondral defect as a simulation of autologous transplantation.

To elucidate the behavior of autologously transplanted mesenchymal cells in osteochondral defects, we followed transplanted cells using green fluorescent protein (GFP) transgenic rats, in which all cells express GFP signals in their cytoplasm and nuclei as transplantation donors. Bone marrow-derived mesenchymal cells, which contain mesenchymal stem cells (MSCs), were obtained from transgenic rats. Then, dense mesenchymal cell masses created by hanging-drop culture were transplanted and fixed with fibrin glue into osteochondral defects of wild-type rats. At 24 weeks after surgery, the defects were repaired with hyaline-like cartilage and subchondral bone. GFP positive cells, indicating transplanted mesenchymal-derived cells, were observed in the regenerated tissues for 24 weeks although GFP positive cells decreased in number with time. Because GFP causes no immunological rejection and requires no chemicals for visualization, transplantation between transgenic and wild-type rats can be regarded as a simulation of autologous transplantation, and the survivability of transplanted cells are able to be followed easily and reliably. Thus, the behavior of transplanted mesenchymal cells was able to be elucidated in vivo by this strategy, and the results could be essential in future tissue engineering for the regeneration of osteochondral defects with original hyaline cartilage and subchondral bone.     

Mass and functional capacity of regenerating muscle is enhanced by myoblast transfer

Morphology and functional capacity of homotopically transplanted extensor digitorum longus muscles (EDL) of adult SCID mice that received 1 × 10⁶ myoblasts [stably transfected to express nuclear localizing β-galactosidase under the control of the myosin light-chain 3F promoter/enhancer] 2 days posttransplantation were evaluated 9 weeks after transplantation, to determine whether the injection of exogenous myoblasts had an effect on muscle regeneration. Regenerated muscles that received exogenous myoblasts were compared to similarly transplanted muscles that received (a) no further treatment, or (b) sham injection of the vehicle (without myoblasts) and to unoperated EDL. Nine weeks after myoblast transfer, myofibers containing donor-derived nuclei could be identified after staining with X-gal solution. Judging from its size and poor functional performance compared to muscles subjected to transplantation only, sham injection provided a secondary trauma to the regenerating muscle from which it failed to fully recover. In comparison to the sham-injected muscle, the myoblast-injected muscles weighed 61% more and had 50% more myofibers and 82% more cross-sectional area occupied by myofibers at the muscles' widest girths. Their absolute twitch and tetanic tensions were threefold and twofold greater, respectively, and their specific twitch and tetanic tensions were 71% and 50% greater, respectively, than those of sham-injected muscles. In many parameters, the regenerating muscle subjected to myoblast transfer equaled or exceeded those of muscles that were transplanted only received only one trauma). Absolute twitch and tetanic tensions were 73% and 65% greater, respectively, and specific twitch tensions of the muscles receiving myoblasts were 50% greater than forces generated by muscles subjected to whole-muscle transplantation only. © 1997 John Wiley & Sons, Inc. J Neurobiol 33: 185–198, 1997     

Transplantation of porcine embryonic stem cells and their derived neuronal progenitors in a spinal cord injury rat model

Background aimsThe purpose of this study was to investigate therapeutic potential of green fluorescent protein expressing porcine embryonic stem (pES/GFP⁺) cells in A rat model of spinal cord injury (SCI).MethodsUndifferentiated pES/GFP⁺ cells and their neuronal differentiation derivatives were transplanted into the contused spinal cord of the Long Evans rat, and in situ development of the cells was determined by using a live animal fluorescence optical imaging system every 15 days. After pES/GFP⁺ cell transplantation, the behavior functional recovery of the SCI rats was assessed with the Basso, Beattie, and Bresnahan Locomotor Rating Scale (BBB scale), and the growth and differentiation of the grafted pES/GFP⁺ cells in the SCI rats were analyzed by immunohistochemical staining.ResultsThe relative green fluorescent protein expression level was decreased for 3 months after transplantation. The pES/GFP⁺-derived cells positively stained with neural specific antibodies of anti-NFL, anti-MBP, anti-SYP and anti-Tuj 1 were detected at the transplanted position. The SCI rats grafted with the D18 neuronal progenitors showed a significant functional recovery of hindlimbs and exhibited the highest BBB scale score of 15.20 ± 1.43 at week 24. The SCI rats treated with pES/GFP⁺-derived neural progenitors demonstrated a better functional recovery.ConclusionsTransplantation of porcine embryonic stem (pES)-derived D18 neuronal progenitors has treatment potential for SCI, and functional behavior improvement of grafted pES-derived cells in SCI model rats suggests the potential for further application of pES cells in the study of replacement medicine and functionally degenerative pathologies.     

内皮祖细胞移植加速鼠颈动脉内皮修复预防再狭窄的研究

目的：以安慰机组作对照,观察EPCs自体移植防治再狭窄的疗效以及该作用与血管再内皮化是否相关。方法：共30只雄性SD大鼠纳入实验,随机均分为假手术组、安慰剂组和EPCs移植组。造模前3周时取血3毫升,M199培养基培养传代,行EPCs鉴定,移植组在球囊损伤后即予尾静脉注射1×10^6个EPCs自体移植。4周后观察再狭窄和再内皮化程度。结果：与安慰剂组相比,EPCs自体移植组再内皮化程度提高,再狭窄程度减轻;EPCs移植组内膜／中膜比值与再内皮化率呈线性负相关。结论：EPCs体外扩增自体移植可预防再狭窄;其机制与加速再内皮化有关。     

Lineage analysis of transplanted individual cells in embryos of Drosophila melanogaster

Summary We describe the results of cell transplantation experiments performed to investigate mesodermal lineages in Drosophila melanogaster, particularly the lineages of the somatic muscles, the visceral muscles and the fat body. Cells to be transplanted were labelled by injecting a mixture of horseradish peroxidase (HRP) and fluorescein-dextran (FITC) in wild-type embryos at the syncytial blastoderm stage. For transplantation cells were removed from the ventral furrow, 8–12 min after the start of gastrulation, and individually transplanted into homotopic or heterotopic locations of unlabelled wild-type hosts of the same age. HRP labelling in the resulting cell clones was demonstrated histochemically in the fully developed embryo; histotypes could be distinguished without ambiguity. Mesodermal cells were already found to be committed to mesodermal fates at the time of transplantation. They developed only into mesodermal derivatives and did not integrate in non-mesodermal organs upon heterotopical transplantation. No evidence was found for commitment to any particular mesodermal organ at the time of transplantation. The majority of somatic muscle clones contributed cells to only one segment. However, clones were not infrequently distributed through two or even three segments. Clones of fat body cells were generally restricted to a small region. However, cells of clones of visceral musculature were widely distributed. With respect to the proliferative abilities of transplanted cells the clones were difficult to interpret due to the syncytial character of the somatic musculature and the fact that the organization of the other organs is poorly understood. Evidence from histological observations of developing normal embryos indicates only three mitoses for mesodermal cells. Clones larger than seven cells were not found when embryos were fixed previous to germ-band shortening; larger clones were found in the fat body and visceral musculature after fixing the embryos at the end of organogenesis. Quantitative considerations suggest that a few mesodermal cells might perform more than three mitoses.     

A preliminary analysis of the balance between Th1 and Th2 cells after CD34+ cell-selected autologous PBSC transplantation

BACKGROUND: CD34+ cell-selected autologous PBSC transplantation (CD34+ APBSCT) is a procedure used for the treatment of patients with malignant disease that is intended to eliminate residual tumor cells from autologous grafts. However, frequent infectious complications after CD34+ APBSCT can occur. A delay of recovery of the absolute number of CD4+ T cells after transplantation was reported to be one disadvantageous factor. As data on T-cell function after CD34+ APBSCT are scanty, we analyzed changes in T-helper cell 1 (Th1) and T-helper cell 2 (Th2) after CD34+ APBSCT to evaluate immune reconstitution. METHODS: Twelve patients underwent APBSCT (CD34+APBSCT group, n=4, and unselected APBSCT, n=8). Peripheral blood (PB) samples were obtained at 2, 4, 8, 12 and 16 weeks after the transplantation. The dynamics of the Th1 and Th2 were analyzed at a single-cell level, using flow cytometry. RESULTS: In the CD34+ APBSCT group, not only the absolute count of CD4+ T cells but also the proportion of Th1 cells in CD4+ T cells and the ratio of Th1 to Th2 after transplantation were significantly decreased at 2 and 4 weeks after transplantation compared with findings in the unselected APBSCT group. DISCUSSION: We suggest that higher rates of infectious complications after CD34+ APBSCT may be due to the inability of residual T cells from the CD34+ cell selection to generate mature T cells that function adequately against infection. Although further study would be required, our preliminary data provide some information on the immune reconstitution after CD34+ APBSCT and differentiation of T lymphocytes into Th1 and Th2 in vivo.     

Human iPSC‐derived neural precursor cells differentiate into multiple cell types to delay disease progression following transplantation into YAC128 Huntington's disease mouse model

ObjectivesTo investigate whether human HLA‐homozygous induced pluripotent stem cell (iPSC)‐derived neural precursor cells (iPSC‐NPCs) can provide functional benefits in Huntington’s disease (HD), we transplanted them into the YAC128 transgenic HD mouse model.Materials and MethodsCHAi001‐A, an HLA‐homozygous iPSC line (A*33:03‐B*44:03‐DRB1*13:02), was differentiated into neural precursor cells, and then, they were transplanted into 6 months‐old YAC128 mice. Various behavioural and histological analyses were performed for five months after transplantation.ResultsMotor and cognitive functions were significantly improved in transplanted animals. Cells transplanted in the striatum showed multipotential differentiation. Five months after transplantation, the donor cells had differentiated into neurons, oligodendrocytes and astrocytes. Transplantation restored DARPP‐32 expression, synaptophysin density, myelin basic protein expression in the corpus callosum and astrocyte function.ConclusionAltogether, these results strongly suggest that iPSC‐NPCs transplantation induces neuroprotection and functional recovery in a mouse model of HD and should be taken forward for clinical trials in HD patients.     

Bone marrow-derived mesenchymal stem cell transplantation does not improve quality of muscle reinnervation or recovery of motor function after facial nerve transection in rats

Recently, we devised and validated a novel strategy in rats to improve the outcome of facial nerve reconstruction by daily manual stimulation of the target muscles. The treatment resulted in full recovery of facial movements (whisking), which was achieved by reducing the proportion of pathologically polyinnervated motor endplates. Here, we posed whether manual stimulation could also be beneficial after a surgical procedure potentially useful for treatment of large peripheral nerve defects, i.e., entubulation of the transected facial nerve in a conduit filled with suspension of isogeneic bone marrow-derived mesenchymal stem cells (BM-MSCs) in collagen. Compared to control treatment with collagen only, entubulation with BM-MSCs failed to decrease the extent of collateral axonal branching at the lesion site and did not improve functional recovery. Post-operative manual stimulation of vibrissal muscles also failed to promote a better recovery following entubulation with BM-MSCs. We suggest that BM-MSCs promote excessive trophic support for regenerating axons which, in turn, results in excessive collateral branching at the lesion site and extensive polyinnervation of the motor endplates. Furthermore, such deleterious effects cannot be overridden by manual stimulation. We conclude that entubulation with BM-MSCs is not beneficial for facial nerve repair.     

Regenerative ability of gastrocnemius muscle under diabetic condition with special reference to SDH & m-ATPase

The present study analyzes the regeneration of skeletal muscle in streptozotocin (STZ) induced diabetic rats. Two weeks later the gastrocnemius muscle from diabetic rats were transplanted into diabetic and normal host to initiate regeneration and the normal gastrocnemius muscle was transplanted in normal and diabetic hosts for comparison. The regenerates were analyzed after 15 and 30 days of transplantation for histochemical (with respect to SDH and m-ATPase) and 7, 14, 21 and 28 days after transplantation for biochemical studies (with respect to SDH and m-ATPase). Least enzymatic activity and the poorest regenerative ability in case of normal muscle in diabetic host (NM-DbH) and comparatively higher enzymatic activity and better regenerative ability in diabetic muscle in normal host (DbM-NH) was observed. The result of this study strongly supports that the normal host environment is crucial for the muscle recovery.     

Fate and protective effect of marrow stromal cells after subretinal transplantation

Engraftment of marrow stromal cells (MSCs) has been proposed as a therapeutic approach for degenerative diseases. In this study we investigated the fate and dynamic progress of grafted MSCs in living retina with the aim of evaluating the use of transplanted MSCs to treat retinal degeneration. Approximately 1×10⁵ gfp -MSCs in 2 μl phosphate-buffered saline were injected into the subretinal space of adult Sprague-Dawley rats. Two weeks later, approximately 0.174%±0.082% of the transplanted cells had survived and diffused into the subretinal space. Nine weeks after transplantation the surviving gfp -MSCs accounted for 0.049%±0.023% of the number of cells injected and were mainly located at the injection site. The same number of MSCs were transplanted into the left eye subretinal space of 3-week-old hereditary retinal degenerative Royal College of Surgeons rats, and phosphate-buffered saline was injected into their right eyes as a control. Five weeks after transplantation, the amount of rudimentary photo-receptors was more significantly increased in grafted eyes than in control eyes. The results indicated that grafted MSCs could survive and rescue retinal degeneration.     

Histological repair of damaged spinal cord tissue from chronic contusion injury of rat: a LM observation

The spinal cord has an intrinsic, limited ability of spontaneous repair; the endogenous repair of damaged tissue starts a few days after spinal cord injury (SCI). To date, however, detailed observation in histology at the injury site has not been well documented. In the present study we analyzed the histological structure of the repaired tissue from injury site of rats 6 or 14 weeks after contusion injury (NYU impactor device, 25 mm height setting) on T10, and rats 8 weeks after transplantation of lamina propria (LP) or acellular lamina propria. We found that the initial repaired tissue can be histologically divided into three different zones, i.e., fibrotic, cellular and axonal. The fibrotic zone consists of invading connective tissue, while the cellular zone is composed of invading, densely compacted Schwann cells. Schwann cells migrate from dorsal roots laterally toward and merge underneath the fibrotic zone, forming the U-shape shell of the cellular zone. The major component of the axonal zone is regenerating axons. Schwann cells myelinate regenerating axons in all three zones. In rats with combination treatments including scar ablation and LP transplantation, both cellular and axonal zones significantly expand in size, resulting in the disappearance of the lesion cavity and the integration of repaired tissue with spared tissue. Olfactory ensheathing cells from transplanted LP may promote the expansion of the cellular and axonal zones through stimulating host Schwann cells, indirectly contributing to tissue repair and axonal regeneration. The ependyma-derived cells may be directly involved in tissue repair, but not contribute to the formation of myelin sheaths.