Rat Bone Marrow-derived Mesenchymal Stem Cells Research Articles

Differential Clearance of Rat and Human Bone Marrow-Derived Mesenchymal Stem Cells from the Brain after Intra-arterial Infusion in Rats

Intra-arterial (IA) delivery of bone marrow-derived mesenchymal stem cells (BM-MSCs) has shown potential as a minimally invasive therapeutic approach for stroke. The aim of the present study was to determine the whole-body biodistribution and clearance of technetium-99m ((99m)Tc)-labeled rat and human BM-MSCs after IA delivery in a rat model of transient middle cerebral artery occlusion (MCAO) using single-photon emission computed tomography (SPECT). Our hypothesis was that xenotransplantation has a major impact on the behavior of cells. Male RccHan:Wistar rats were subjected to sham operation or MCAO. Twenty-four hours after surgery, BM-MSCs (2 × 10(6) cells/animal) labeled with (99m)Tc were infused into the external carotid artery. Whole-body SPECT images were acquired 20 min, 3 h, and 6 h postinjection, after which rats were sacrificed, and organs were collected and weighed for measurement of radioactivity. The results showed that the majority of the cells were located in the brain and especially in the ipsilateral hemisphere immediately after cell infusion both in sham-operated and MCAO rats. This was followed by fast disappearance, particularly in the case of human cells. At the same time, the radioactivity signal increased in the spleen, kidney, and liver, the organs responsible for destroying cells. Further studies are needed to demonstrate whether differential cell behavior has any functional impact.

Effects of immunosuppressive drugs on viability and susceptibility of adipose- and bone marrow-derived mesenchymal stem cells.

The immunomodulatory potential of cell therapies using adipose-derived stem cells (ASCs) and bone marrow-derived mesenchymal stem cells (BM-MSCs) has been studied in vascularized composite allotransplantation (VCA). Most cell therapy-based experimental and clinical protocols integrate some degree of recipient conditioning/induction with antibodies or other immunosuppressive agents. We investigated the susceptibility of ASCs and BM-MSCs to anti-lymphocyte serum (ALS) and tacrolimus. Rat ASCs and BM-MSCs were exposed to varying concentrations of tacrolimus and ALS in vitro. Serum from ALS-treated animals was added to cell cultures. Viability, susceptibility, and cytotoxicity parameters were evaluated. ALS inhibited ASC and BM-MSC viability and susceptibility in vitro in a dose-dependent manner. ASCs were more susceptible to both ALS and tacrolimus than BM-MSCs. Trypsinized and adherent ASCs were significantly smaller than BM-MSCs. This is the first report on the viability and susceptibility characteristics of BM-MSCs or ASCs to collateral effects of ALS and tacrolimus. These in vitro insights may impact choice of cell type as well as concomitant conditioning agents and the logistical coordination of the timing, dosing, and frequency of drug or cell therapy in solid organ transplantation or VCA protocols.

Lysophosphatidic acid rescues bone mesenchymal stem cells from hydrogen peroxide-induced apoptosis.

The increase of reactive oxygen species in infracted heart significantly reduces the survival of donor mesenchymal stem cells, thereby attenuating the therapeutic efficacy for myocardial infarction. In our previous study, we demonstrated that lysophosphatidic acid (LPA) protects bone marrow-derived mesenchymal stem cells (BMSCs) against hypoxia and serum deprivation-induced apoptosis. However, whether LPA protects BMSCs from H2O2-induced apoptosis was not examined. In this study, we report that H2O2 induces rat BMSC apoptosis whereas LPA pre-treatment effectively protects BMSCs from H2O2-induced apoptosis. LPA protection of BMSC from the induced apoptosis is mediated mostly through LPA3 receptor. Furthermore, we found that membrane G protein Gi2 and Gi3 are involved in LPA-elicited anti-apoptotic effects through activation of ERK1/2- and PI3 K-pathways. Additionally, H2O2 increases levels of type II of light chain 3B (LC3B II), an autophagy marker, and H2O2-induced autophagy thus protected BMSCs from apoptosis. LPA further increases the expression of LC3B II in the presence of H2O2. In contrast, autophagy flux inhibitor bafilomycin A1 has no effect on LPA's protection of BMSC from H2O2-induced apoptosis. Taken together, our data suggest that LPA rescues H2O2-induced apoptosis mainly by interacting with Gi-coupled LPA3, resulting activation of the ERK1/2- and PI3 K/AKT-pathways and inhibition caspase-3 cleavage, and LPA protection of BMSCs against the apoptosis is independent of it induced autophagy.

Clinical and radiographic characterization of xenotransplantation of rat bonemarrow-derived mesenchymal stem cells for repair of radial defects of rabbit

This study aimed to evaluate the clinical and radiographic aspects of xenogenic transplantation of rat bone marrow-derived mesenchymal stem cells (MSCs) for the repair of radial bone defects of rabbit. Bone marrow derived MSCs collected from Wistar rats were expanded, differentiated, and labeled in the laboratory. In the fourth passage, the cultures were pelleted in aliquots of 107 cells/50 μL and transplanted in situ into the lesions. Thirty-six rabbits were used in the in vivo study. In all animals, defects were created by removing a bone segment of 1.0 cm in length in the right radius. The rabbits were divided into four experimental groups: the control group (CG) received percutaneously administered 50 μL of phosphate buffer (PBS) in the radial bone defect region 24 h after lesion creation; group 1 (G1) had the radial bone defect filled with absorbable gelatin sponge soaked with 50 μL of PBS during the surgery; group 2 (G2) had the radial bone defect filled with absorbable gelatin sponge soaked with the MSC pellet; and group 3 (G3) received percutaneously the MSC pellet in the radial bone defect region 24 h after lesion creation. No clinical and radiographic changes consistent with cellular rejection were observed. Percutaneous MSC xenotransplantation contributed to the repair of experimental radial bone defects.

Chondrogenic differentiation of ChM-I gene transfected rat bone marrow-derived mesenchymal stem cells on 3-dimensional poly (L-lactic acid) scaffold for cartilage engineering.

We have explored the role of Chondromodulin-I (ChM-I) in chondrogenesis of bone marrow-derived mesenchymal stem cells (BMSCs) in 3-dimensional (3D) scaffold for cartilage tissue engineering. BMSCs of Sprague Dawley (SD) rats were cultured on poly-(L-lactic acid) [PLLA] scaffolds with different pore sizes (80-200 μm, 200-450 μm) with or without surface modification by chitosan. Cell viability, proliferation, and morphology were measured using confocal microscope and the CCK-8 method. Untransfected BMSCs, BMSCs expressing pcDNA3.1(+), BMSCs expressing plasmid pcDNA3.1 (+)/ChM-I were cultured on 3D scaffolds in standard growth medium or transforming growth factor-β1 (TGF-β1) supplemented chondrogenic induction medium in vitro for 3 weeks and the expression of collagen type II was determined. Cell-scaffolds constructs were implanted subcutaneously for 3 months in vivo. BMSCs had a higher viability and proliferation in PLLA scaffolds of pore size 200-450 μm than that of 80-200 μm, and surface modification with chitosan did not enhance cell attachment. The ChM-I gene enhanced chondrogenesis and increased collagen type II synthesis. Immunohistochemistry from in vivo study showed enhanced cartilage regeneration in BMSCs expressing pcDNA3.1 (+)/ChM-I on 3D PLLA scaffolds. It also demonstrated that TGF-β1 might promote chondrogenesis of rat BMSCs by synergizing with the ChM-I gene. ChM-I could be beneficial to future applications in cartilage repair.

Mesenchymal stem cells and ligand incorporation in biomimetic poly(ethylene glycol) hydrogels significantly improve insulin secretion from pancreatic islets.

The main goal of this study was to investigate pancreatic islet function with mesenchymal stem cells (MSCs) in a ligand-functionalized poly(ethylene glycol) (PEG) hydrogel for the treatment of type 1 diabetes (T1D). Rat bone marrow-derived MSCs (rBM-MSCs) were encapsulated within synthetic PEG hydrogel, and cell viability and apoptosis within this 3D environment was examined in detail. ATP content and caspase-3 activity of encapsulated MSCs showed that fibronectin-derived RGDS, laminin-derived IKVAV and/or insulinotropic glucagon-like peptide (GLP-1) were required to maintain MSC survival. Incorporation of these peptides into the hydrogel environment also improved pancreatic islet viability, where combinations of peptides had altered effects on islet survival. GLP-1 alone was the leading stimulator for insulin secretion. Cell adhesion peptides RGDS and IKVAV improved insulin secretion only when they were used in combination, but could not surpass the effect of GLP-1. Further, when pancreatic islets were co-encapsulated with MSCs within synthetic PEG hydrogel, a two-fold increase in the stimulation index was measured. Synergistic effects of MSCs and peptides were observed, with a seven-fold increase in the stimulation index. The results are promising and suggest that simultaneous incorporation of MSCs and ECM-derived peptides and/or GLP-1 can improve pancreatic islet function in response to altered glucose levels in the physiological environment. Copyright © 2014 John Wiley & Sons, Ltd.

Conditioned medium from mesenchymal stem cells enhances the migration of hepatoma cells through CXCR4 up-regulation and F-actin remodeling.

Interactions between tumors and mesenchymal stem cells (MSCs) can regulate cancer cell behavior and cancer progression. Rat bone marrow-derived MSCs (rMSCs) were isolated and purified by Percoll density gradient centrifugation. Conditioned media from rMSCs (MSC-CM) was prepared, and its role in cancer cell migration and the underlying molecular mechanism were investigated. MSC-CM increased the migration and up-regulated the expression of CXC chemokine receptor 4 (CXCR4) in rat hepatoma cells (CBRH-7919). F-actin remodeling was observed, and the Young's modulus was decreased in CBRH-7919 cells. A CXCR4 inhibitor suppressed the MSC-CM-induced CXCR4 expression and migration, restored the decrease in the Young's modulus and disrupted the formation of F-actin. MSC-CM thus promotes CBRH-7919 cell migration by lessening cell stiffness and increasing F-actin formation through up-regulation of CXCR4 expression. MSC-CM may therefore have a positive impact on cancer metastases and underlines a potential safety issue associated with clinical applications of MSCs.

Transcription factor Mohawk controls tenogenic differentiation of bone marrow mesenchymal stem cells in vitro and in vivo.

Mohawk homeobox (MKX) has been demonstrated as a tendon/ligament specific transcription factor. The aim of this study was to investigate the role of MKX in ligament/tenogenic differentiation of bone marrow derived mesenchymal stem cells (BMMSCs). Human BMMSCs were treated with 50 ng/ml BMP-12 or transduced with MKX or scleraxis (SCX) adenoviral vector. Gene expression analysis was performed by quantitative reverse transcribed polymerase chain reaction (qRT-PCR). Rat BMMSCs were seeded in a collagen scaffold and transplanted into a rat Achilles tendon defect model. Tenogenesis related gene expressions and histological features were analyzed. BMP-12 induced tenogenesis in BMMSCs as indicated by increased COL1a1, TNXB, DCN and SCX mRNA, and MKX expression increased simultaneously. Rat BMMSCs enhanced defect repair and were still detectable 3 weeks after transplantation. Increased expressions of COL1a1, TNC and TNMD in vivo were also correlated with upregulated MKX. Adenoviral MKX promoted expression of COL1a1, TNXB, and TNMD in BMMSCs. This study demonstrated that MKX gene expression is enhanced during the tenogenic differentiation of BMMSCs in vitro and in vivo, and the adenoviral overexpression of MKX increases tendon extracellular matrix gene expression and protein production. Thus, MKX is a key factor for tenogenic differentiation of MSCs.

Study on Compatibility of Self-Assembly Peptide RADA16-I, PLGA and PS Scafolds and BMSCs

Objective: To observe the ability of self-assembly peptide RADA16-І hydrogel, poly (lactic-co-glycolic acid) (PLGA) and polystyrene (PS) scaffolds in supporting the adherent growth of rat bone marrow-derived mesenchymal stem cells (BMSCs). Methods: The rat BMSCs were isolated and purified by density gradient centrifugation and adherent culture. The 3rd passage of BMSCs were used to induced into adipocytes and osteoblasts by inductive medium in vitro, and labeled by infection of adenovirus carried with green fluorescent protein. BMSCs were inoculated on RADA16-І hydrogel, PLGA and PS scaffolds to form cell-scaffold complex. Adhesion rates of BMSCs on different scaffolds were investigated, and cell proliferation was tested by MTT method. Results: Cultured BMSCs presented high uniformity and had multilineage differentiation potential. Adhesion rates of BMSCs on RADA16-І hydrogel, PLGA and PS scaffolds were 92.51%, 78.36% and 59.79% respectively. BMSCs cultured on RADA16-І hydrogel showed higher ability of proliferation than those cultured on PLGA and PS scaffolds after incubation for 7 days (P < 0.05). Conclusion: RADA16-І hydrogel is more suitable than PLGA and PS for attachment and growth of BMSCs.

Cultivation and identification of rat bone marrow-derived mesenchymal stem cells

Bone marrow‑derived mesenchymal stem cells (BMSCs) have the potential to form a variety of mesenchymal tissue types, which are a source of cells for bone tissue engineering applications. The present study attempted to establish an effective and convenient method for culturing BMSCs. Total bone marrow cells, which were harvested from rat femurs, were cultured and BMSCs were selected and expanded through passaging invitro. Furthermore, the biological properties of BMSCs were investigated, specific surface antigen expression was assessed using flow cytometry and the multipotent differentiation potential characteristics were demonstrated using standard invitro conditions. Monoptychial heterogeneous cells were obtained. A total of 98.4% of cells at passage3 expressed cluster of differentiation (CD)29 and CD90, but not CD45. The cells were able to differentiate into osteogenic and adipogenic cells. In conclusion, BMSCs that are isolated from the rat bone marrow and exhibit the identified characteristics may be used as seed cells in bone tissue engineering.

Bone Marrow Mesenchymal Stem Cell-Derived Microvesicles Protect Rat Pheochromocytoma PC12 Cells from Glutamate-Induced Injury via a PI3K/Akt Dependent Pathway

Studies have suggested that mesenchymal stem cells (MSCs) can protect neuronal cells from excitotoxicity, but the underlying mechanisms are still remaining elusive. In the study, we show that microvesicles released by rat bone marrow-derived MSCs (rBMSC-MVs) protect rat pheochromocytoma PC12 cells from glutamate-induced excitotoxicity. BMSC-MVs upregulate Akt phosphorylation and Bcl-2 expression, downregulate Bax expression, and reduce the cleavage of caspase-3 in glutamate-treated PC12 cells. Such protective effects are partially abrogated by inhibiting PI3K, indicating that rBMSC-MVs act via the PI3K/Akt pathway. Transplantation of rBMSC-MVs may, therefore, be a promising strategy to treat cerebral injury or some other neuronal diseases involving excitotoxicity.

Effects of Apelin-13 on Rat Bone Marrow-Derived Mesenchymal Stem Cell Proliferation Through the AKT/GSK3β/Cyclin D1 Pathway

The migration and proliferation of bone marrow-derived mesenchymal stem cells (BMSC) is critical to treatment of ischemic injury. Apelin is a recently discovered vasoactive peptide, which has been demonstrated to be the endogenous ligand for the previously orphaned G protein-coupled receptor, angiotensin-like 1 receptor. Apelin has mitogenic effects on a wide variety of cell types. However, the effects of apelin on BMSC proliferation have not been evaluated. We hypothesize that the peptide apelin-13 may enhance BMSC proliferation. Rat BMSC obtain from the bone marrow of 3- to 4-month-old SD rats. There are novel data suggesting that apelin-13 significantly simulates BMSC proliferation and promotes the expression of p-AKT, p-GSK3β and cyclin D1 in a concentration-dependent manner. Apelin-13-induced the increases of p-AKT, p-GSK3β and cyclin D1 could be abolished by LY294002 (AKT inhibitor) which prevents apelin-13-induced BMSC proliferation. However, LiCl (GSK inhibitor) up-regulates the expression of p-GSK3β and cyclin D1, promotes BMSC proliferation, which enhances the proliferation effect of apelin-13 obviously. In conclusion, the AKT/GSK3β/cyclin D1 signaling pathway is involved in apelin-13-induced BMSC proliferation.

Stem cells with FGF4-bFGF fused gene enhances the expression of bFGF and improves myocardial repair in rats

The aim of this study was to investigate whether the modification of bone marrow-derived mesenchymal stem cells (BMSCs) with the fused FGF4 (fibroblast growth factor 4)-bFGF (basic fibroblast growth factor) gene could improve the expression and secretion of BFGF, and increase the efficacies in repairing infarcted myocardium. We used In-Fusion technique to construct recombinant lentiviral vectors containing the individual gene of bFGF, enhanced green fluorescent protein (EGFP), or genes of FGF4-bFGF and EGFP, and then transfected these lentiviruses into rat BMSCs. We conducted an in vitro experiment to compare the secretion of bFGF in BMSCs infected by these lentiviruses and also examined their therapeutic effects in the treatment of myocardial infraction in a rodent study. Sixty rats were tested in the following five conditions: Group-SHAM received only sham operation as controls; Group-AMI received only injection of placebo PBS buffer; Group-BMSC, Group-bFGF and Group-FGF4-bFGF received implantation of BMSCs with empty lentivirus, bFGF lentivirus, and FGF4-bFGF lentivirus, respectively. Our results found out that the transplanted FGF4-bFGF BMSCs had the highest survival rate, and also the highest myocardial expression of bFGF and microvascular density as evidenced by Western blotting and immunohistochemistry, respectively. As compared to other groups, the Group-FGF4-BFGF rats had the lowest myocardial fibrotic fraction, and the highest left ventricular ejection fraction. These results suggest that the modification of BMSCs with the FGF4-bFGF fused gene can not only increase the expression of bFGF but also improve its secretion. The FGF4-bFGF BMSCs thus can enhance the survival of the transplanted cells, diminish myocardial fibrosis, promote myocardial angiogenesis, and improve cardiac functions.

Transplantation of bone marrow mesenchymal stem cells on collagen scaffolds for the functional regeneration of injured rat uterus

Serious injuries of endometrium in women of reproductive age are often followed by uterine scar formation and a lack of functional endometrium predisposing to infertility or miscarriage. Bone marrow-derived mesenchymal stem cells (BM-MSCs) have shown great promise in clinical applications. In the present study, BM-MSCs loaded onto degradable collagen membranes were constructed. Collagen membranes provided 3-dimmensional architecture for the attachment, growth and migration of rat BM-MSCs and did not impair the expression of the stemness genes. We then investigated the effect of collagen/BM-MSCs constructs in the healing of severe uterine injury in rats (partial full thickness uterine excision). At four weeks after the transplantation of collagen/BM-MSCs constructs, BM-MSCs were mainly located to the basal membrane of regenerative endometrium. The wounded tissue adjacent to collagen/BM-MSCs constructs expressed higher level of bFGF, IGF-1, TGFβ1 and VEGF than the corresponding tissue in rats receiving collagen construct alone or in spontaneous regeneration group. Moreover, the collagen/BM-MSCs system increased proliferative abilities of uterine endometrial and muscular cells, facilitated microvasculature regeneration, and restored the ability of endometrium to receive the embryo and support its development to a viable stage. Our findings indicate that BM-MSCs may support uterine tissue regeneration.

Suppression of MicroRNA‐203 improves survival of rat bone marrow mesenchymal stem cells through enhancing PI3K‐induced cellular activation

As a group of heterogeneous multipotent cells, mesenchymal stem cells (MSCs) have potential in treatment of a variety of clinical diseases. However, the low survival of the transplanted MSCs reduced their therapeutic effects. In this study, we revealed that rno-miR-203 suppressed activity and colony formation and enhanced apoptosis of the rat bone marrow-derived MSCs (BM-MSCs). Using bioinformatics analysis, we found a potential miR-203 binding site within rat phosphatidylinositol 3-kinase (PI3K) 3'UTR, and fluorescent reporter experiments validated the direct and negative regulation of PI3K expression by miR-203 through this site. Ectopic expression of PI3K rescued BM-MSCs from depressed activity induced by miR-203, and suppression of PI3K attenuated the increased BM-MSCs activity by miR-203 inhibitor treatment. Moreover, miR-203 blocking partly protected BM-MSCs from impairment caused by low nutrition. We conclude that inhibition of endogenous miR-203 elevated PI3K expression, which may strengthen PI3K/Akt pathway and promote BM-MSCs activity and survival. © 2014 IUBMB Life, 66(3):220-227, 2014.

Platelet-derived growth factor BB mediates the glioma-induced migration of bone marrow-derived mesenchymal stem cells by promoting the expression of vascular cell adhesion molecule-1 through the PI3K, P38 MAPK and NF-κB pathways

Platelet-derived growth factor BB (PDGFBB) has been shown to activate the migration of bone marrow-derived mesenchymal stem cells (BM-MSCs), and to contribute to mediating the tropism of BM-MSCs towards gliomas. However, the exact mechanism of this migratory behavior remains to be elucidated. The present study investigated the role of vascular cell adhesion molecule-1 (VCAM-1) in the PDGFBB-induced migration of BM-MSCs, the effect of PDGFBB on VCAM-1 expression of BM-MSCs and related signaling pathways involved in this process. Rat BM-MSCs were isolated and cultured by their characteristics of adherence to plastics. The concentrations of PDGFBB in the conditioned medium of C6 and U87 cells were measured using the ELISA method. In vitro migration assays using a VCAM-1 blocking antibody were performed to evaluate the role of VCAM-1 in PDGFBB-induced migration of BM-MSCs. The effect of rat recombinant PDGFBB on VCAM-1 expression of BM-MSCs was studied by RT-PCR and western blotting. LY294002, SB203580, PD98059, SP600125 and BAY11-7082 were used to explore the role of PI3K, p38 MAPK, MEK, JNK and NF-κB in the related intracellular signal transduction of PDGFBB stimulation on VCAM-1 expression of BM-MSCs. The data demonstrated that the neutralization of VCAM-1 inhibited the migration of BM-MSCs induced by PDGFBB. Additionally, PDGFBB stimulation increased VCAM-1 expression of BM-MSCs, which could be inhibited by LY294002, SB203580 and BAY11-7082. It is reasonable to conclude that PDGFBB significantly enhanced the expression of VCAM-1 in BM-MSCs, which facilitated the migration of BM-MSCs towards PDGFBB. PI3K, p38 MAPK and NF-κB were involved in the signal transduction of this process.

HIF-1-modified BMSCs improve migration and reduce neuronal apoptosis after stroke in rats

Bone marrow-derived mesenchymal stem cells (BMSCs) have been demonstrated ameliorating neurologic deficits after stroke. Hypoxia-inducible factor-1 (HIF-1), the key regulator of cellular responses to low oxygen concentration, can activate multiple genes involving in crucial aspects for neurologic recovery. In this study, we present that rat BMSCs overexpression of HIF-1 α showed higher expression of HIF-1 target genes in HIF-1-BMSCs, including CXCR4, EPO, and VEGF. BMSCs-mHIF-1α also exhibited an enhanced mobility towards the ischemic area within rat brain. Neural cell apoptosis in ischemic brain shown less severe in rats transplanted with HIF-1-BMSCs. Furthermore, the number of cells expressing neural progenitor markers PAX6 and DCX were increased in BMSCs-mHIF-1α-transplanted rats. These results suggest that HIF-1α in BMSCs reduces neuronal apoptosis and promotes neurogenesis after stroke in rats.

Role of Injured Pancreatic Extract Promotes Bone Marrow-Derived Mesenchymal Stem Cells Efficiently Differentiate into Insulin-Producing Cells

Mesenchymal stem cells (MSCs) can be successfully induced to differentiate into insulin-producing cells （IPCs) by a variety of small molecules and cytokines in vitro. However, problems remain, such as low transdifferentiation efficiency and poor maturity of trans-differentiated cells. The damaged pancreatic cells secreted a large amount of soluble proteins, which were able to promote pancreative islet regeneration and MSCs differentiation. In this study, we utilized the rat injured pancreatic tissue extract to modulate rat bone marrow-derived MSCs differentiation into IPCs by the traditional two-step induction. Our results showed that injured pancreatic tissue extract could effectively promote the trans-differentiation efficiency and maturity of IPCs by the traditional induction. Moreover, IPCs were able to release more insulin in a glucose-dependent manner and ameliorate better the diabetic conditions of streptozotocin (STZ)-treated rats. Our study provides a new strategy to induce an efficient and directional differentiation of MSCs into IPCs.

Transplantation of bone marrow–derived mesenchymal stem cells after regional hepatic irradiation ameliorates thioacetamide-induced liver fibrosis in rats

BackgroundRecent studies have demonstrated that bone marrow–derived mesenchymal stem cells (BM-MSCs) can potentially revert liver fibrosis, but it is not known if preparative hepatic irradiation (HIR) contributes to the therapeutic effect of transplanted BM-MSCs. In this study, we investigate the effects of HIR on transplanted BM-MSCs in cirrhotic rats and the underlying mechanism by which mesenchymal stem cells (MSCs) relieve liver fibrosis. Materials and methodsThe BM-MSCs from male rats were labeled with CM-Dil and injected via portal vein into two groups of thioacetamide-induced cirrhotic rats, and the controls were injected with the same volume of saline. The right hemiliver of one cirrhotic rat group was irradiated (15 Gy) 4 d before transplantation. Liver function tests and histologic experiments were performed, and the liver population of BM-MSCs was estimated. ResultsThe transplantation of MSCs alleviated liver fibrosis and reduced expression of transforming growth factor-β1, Smad2, collagen type Ⅰ, and α-SMA. HIR preconditioning promoted homing and repopulation of MSCs and resulted in better treatment outcomes. ConclusionsHIR preconditioning enhances the effect of BM-MSCs in improving thioacetamide-induced liver fibrosis in rats by promoting their homing and repopulation. BM-MSCs may function by inhibiting transforming growth factor-β1-Smad signaling pathway in the liver.

Platelet rich plasma clot releasate preconditioning induced PI3K/AKT/NFκB signaling enhances survival and regenerative function of rat bone marrow mesenchymal stem cells in hostile microenvironments.

Mesenchymal stem cells (MSCs) have been optimal targets in the development of cell based therapies, but their limited availability and high death rate after transplantation remains a concern in clinical applications. This study describes novel effects of platelet rich clot releasate (PRCR) on rat bone marrow-derived MSCs (BM-MSCs), with the former driving a gene program, which can reduce apoptosis and promote the regenerative function of the latter in hostile microenvironments through enhancement of paracrine/autocrine factors. By using reverse transcription-polymerase chain reaction, immunofluorescence and western blot analyses, we showed that PRCR preconditioning could alleviate the apoptosis of BM-MSCs under stress conditions induced by hydrogen peroxide (H2O2) and serum deprivation by enhancing expression of vascular endothelial growth factor and platelet-derived growth factor (PDGF) via stimulation of the platelet-derived growth factor receptor (PDGFR)/PI3K/AKT/NF-κB signaling pathways. Furthermore, the effects of PRCR preconditioned GFP-BM-MSCs subcutaneously transplanted into rats 6 h after wound surgery were examined by histological and other tests from days 0-22 after transplantation. Engraftment of the PRCR preconditioned BM-MSCs not only significantly attenuated apoptosis and wound size but also improved epithelization and blood vessel regeneration of skin via regulation of the wound microenvironment. Thus, preconditioning with PRCR, which reprograms BM-MSCs to tolerate hostile microenvironments and enhance regenerative function by increasing levels of paracrine factors through PDGFR-α/PI3K/AKT/NF-κB signaling pathways would be a safe method for boosting the effectiveness of transplantation therapy in the clinic.