Rabbit Mesenchymal Stem Cells Research Articles

Differentiated Stem Cells Derived from Rabbit Adipose Tissue Exhibited in ‎Vitro Adipogenesis and Osteogenesis

The multipotent characteristic of rabbit adipose-derived stem cells makes them available and ‎convenient sources for isolating mesenchymal stem cells. The aim of this study was to assess ‎the differentiation in rabbit adipose-derived stem cells pre-committed to produce several ‎mesenchymal lineages in response to inductive extracellular cues to multipotent stromal cells. ‎Three grams of adipose tissue was taken from a subcutaneous region of the nape of the neck ‎and was carefully isolated to obtain mesenchymal stem cells for expanded by fourth passage. In ‎the 4th passage, active growth of mesenchymal stem cells was observed. Furthermore, the ‎research demonstrated the inherent ability of rabbit MSCs to induce differentiation in ‎osteogenic and adipogenic lineages. These mesenchymal stem cells were successfully isolated ‎from adipose tissue which differentiated into either osteocytes or adipocyte-like cells after 21 ‎and 14 days of culturing in specific osteogenic and adipogenic media, respectively. The ‎remarkable differentiation potential of rabbit mesenchymal stem cells is indicated by ‎mineralized deposition to the osteocytes and lipid droplets accumulated in the cytoplasm lipid ‎vacuoles in the adipocytes‎.

C-C Motif Chemokine Ligand 2 Enhances Macrophage Chemotaxis, Osteogenesis, and Angiogenesis during the Inflammatory Phase of Bone Regeneration.

Local cell therapy has recently gained attention for the treatment of joint diseases and fractures. Mesenchymal stem cells (MSCs) are not only involved in osteogenesis and angiogenesis, but they also have immunomodulatory functions, such as inducing macrophage migration during bone regeneration via macrophage crosstalk. C-C motif chemokine ligand 2 (CCL2), a known inflammatory mediator, is associated with the migration of macrophages during inflammation. This study examined the utility of CCL2 as a therapeutic target for local cell therapy. Using lentiviral vectors for rabbit MSCs, genetically modified CCL2 overexpressing MSCs were generated. Osteogenic differentiation assays were performed using MSCs with or without macrophages in co-culture, and cell migration assays were also performed. Additionally, co-cultures were performed with endothelial cells (ECs), and angiogenesis was evaluated using a tube formation assay. Overexpression of CCL2 did not affect bone formation under monoculture conditions but promoted chemotaxis and osteogenesis when co-cultured with macrophages. Furthermore, CCL2-overexpression promoted tube formation in co-culture with ECs. These results suggest that CCL2 induces macrophage chemotaxis and osteogenesis by promoting crosstalk between MSCs and macrophages; CCL2 also stimulates ECs to induce angiogenesis. These findings indicate that CCL2 may be a useful therapeutic target for local cell therapy in areas of bone loss.

Using loofah reinforced chitosan-collagen hydrogel based scaffolds in-vitro and in-vivo; healing in cartilage tissue defects

The herein article aims to report a new scaffold design as a loofah-reinforced chitosan-collagen hydrogel composite scaffold with three different cross-linker concentrations (0.1, 0.3, and 0.5 wt. /v%). From the analyses, the scaffold crosslinked with 0.5% genipin; collagen-chitosan hydrogel scaffold reinforced with loofah (L-CCol5) was found to be suitable for further in vitro and in vivo studies due to its interconnected porous structure, water content (∼ 97%) and tan delta (0.221 at 1 Hz) values comparable to that of cartilage tissue. In vitro analyses depicted that the L-CCol5 scaffold supported rabbit mesenchymal stem cells (rMSCs) adhesion and proliferation with its non-cytotoxic feature. Moreover, in vivo cartilage healing studies were performed using New Zealand male rabbits in three groups: empty control, cell-free scaffold, and rMSCs-laden scaffold. The elastic moduli of these three groups were 0.69, 0.90, and 1.18 MPa, respectively. Besides, microcomputer tomography (MicroCT) scannings supported the in vivo biomechanical analyses as cell-laden scaffolds showed better osteochondral healing. It can be concluded that the L-CCol5 scaffold could be a promising construct in osteochondral tissue engineering applications. The findings revealed that osteochondral remodeling precedes articular cartilage, providing insight into tailored therapeutic approaches, disease progress, and treatment consequences.

Comparison of Autografts and Biodegradable 3D-Printed Composite Scaffolds with Osteoconductive Properties for Tissue Regeneration in Bone Tuberculosis.

Tuberculosis remains one of the major health problems worldwide. Besides the lungs, tuberculosis affects other organs, including bones and joints. In the case of bone tuberculosis, current treatment protocols include necrectomy in combination with conventional anti-tuberculosis therapy, followed by reconstruction of the resulting bone defects. In this study, we compared autografting and implantation with a biodegradable composite scaffold for bone-defect regeneration in a tuberculosis rabbit model. Porous three-dimensional composite materials were prepared by 3D printing and consisted of poly(ε-caprolactone) filled with nanocrystalline cellulose modified with poly(glutamic acid). In addition, rabbit mesenchymal stem cells were adhered to the surface of the composite scaffolds. The developed tuberculosis model was verified by immunological subcutaneous test, real-time polymerase chain reaction, biochemical markers and histomorphological study. Infected animals were randomly divided into three groups, representing the infection control and two experimental groups subjected to necrectomy, anti-tuberculosis treatment, and plastic surgery using autografts or 3D-composite scaffolds. The lifetime observation of the experimental animals and analysis of various biochemical markers at different time periods allowed the comparison of the state of the animals between the groups. Micro-computed tomography and histomorphological analysis enabled the evaluation of osteogenesis, inflammation and cellular changes between the groups, respectively.

Safety of Allogeneic Mesenchymal Stem Cell Seeding of NeuraGen Nerve Guides in a Rabbit Model.

Mesenchymal stem cells (MSCs) stimulate nerve and tissue regeneration and are primed for clinical translation. Application of autologous MSCs is limited by requirements for expedient harvesting procedures, proliferative expansion to increase number of cells, and reduced regenerative potential due to aging or pathological conditions. Because MSCs are immune privileged, allogeneic MSCs may serve as "off-the-shelf" cell-based reconstructive treatments to support nerve repair. Therefore, we examined the safety and immune response parameters of allogeneic MSCs seeded on NeuraGen® Nerve Guides (NNGs) in a rabbit model. NNGs with or without allogeneic rabbit MSCs were applied to rabbit sciatic nerves. Randomly assigned treatment included group I (no surgery control, n = 3) or groups II and III (sciatic nerve wrapped with unseeded or allogeneic MSC-seeded NNGs; n = 5/group). Rabbits were euthanized after 2 weeks to monitor functional recovery by histological evaluation of sciatic nerves and tibialis anterior (TA) muscle. Host reactions to allogeneic MSCs were analyzed by assessment of body and tissue weight, temperature, as well as hematological parameters, including white blood cell count (WBC), spleen histology, and CD4+ and CD8+ T lymphocytes. Histological analyses of nerves and spleen were all unremarkable, consistent with absence of overt systemic and local immune responses upon allogeneic MSC administration. No significant differences were observed in WBC or CD4+ and CD8+ T lymphocytes across unseeded and seeded treatment groups. Thus, allogenic MSCs are safe for use and may be considered in lieu of autologous MSCs in translational animal studies as the basis for future clinical nerve repair strategies. Impact statement Autologous mesenchymal stem cells (MSC) have been reported to enhance nerve regeneration when used in conjunction with nerve graft substitutes. However, autologous stem cell sources delay treatment and may be susceptible to age- or disease-related dysfunctions. In this study, we investigated the safety of allogeneic MSCs and the optimal number of cells for nerve conduit delivery in a rabbit model. When compared with unseeded nerve conduits, allogeneic MSC-seeded conduits did not induce a systemic or local immune response. The findings of this study will ultimately facilitate the clinical translation of a universal donor cell-based treatment option for nerve defects.

Co-aggregation of MSC/chondrocyte in a dynamic 3D culture elevates the therapeutic effect of secreted extracellular vesicles on osteoarthritis in a rat model

Extracellular vesicles (EVs) have therapeutic effects on osteoarthritis (OA). Some recent strategies could elevate EV's therapeutic properties including cell aggregation, co-culture, and 3D culture. It seems that a combination of these strategies could augment EV production and therapeutic potential. The current study aims to evaluate the quantity of EV yield and the therapeutic effect of EVs harvested from rabbit mesenchymal stem cells (MSCs) aggregates, chondrocyte aggregates, and their co-aggregates in a dynamic 3D culture in a rat osteoarthritis model. MSC and chondrocytes were aggregated and co-aggregated by spinner flasks, and their conditioned medium was collected. EVs were isolated by size exclusion chromatography and characterized in terms of size, morphology and surface markers. The chondrogenic potential of the MSC-ag, Cho-ag and Co-ag EVs on MSC micromass differentiation in chondrogenic media were assessed by qRT-PCR, histological and immunohistochemical analysis. 50 μg of MSC-ag-EVs, Cho-ag-EVs and Co-ag-EVs was injected intra-articularly per knee of OA models established by monoiodoacetate in rats. After 8 weeks follow up, the knee joints were harvested and analyzed by radiographic, histological and immunohistochemical features. MSC/chondrocyte co-aggregation in comparison to MSC or chondrocyte aggregation could increase EV yield during dynamic 3D culture by spinner flasks. Although MSC-ag-, Cho-ag- and Co-ag-derived EVs could induce chondrogenesis similar to transforming growth factor-beta during in vitro study, Co-ag-EV could more effectively prevent OA progression than MSC-ag- and Cho-ag-EVs. Our study demonstrated that EVs harvested from the co-aggregation of MSCs and chondrocytes could be considered as a new therapeutic potential for OA treatment.

Fabrication of 3D Printed poly(lactic acid) strut and wet-electrospun cellulose nano fiber reinforced chitosan-collagen hydrogel composite scaffolds for meniscus tissue engineering.

The main goal of the study was to produce chitosan-collagen hydrogel composite scaffolds consisting of 3D printed poly(lactic acid) (PLA) strut and nanofibrous cellulose for meniscus cartilage tissue engineering. For this purpose, first PLA strut containing microchannels was incorporated into cellulose nanofibers and then they were embedded into chitosan-collagen matrix to obtain micro- and nano-sized topographical features for better cellular activities as well as mechanical properties. All the hydrogel composite scaffolds produced by using three different concentrations of genipin (0.1, 0.3, and 0.5%) had an interconnected microporous structure with a swelling ratio of about 400% and water content values between 77 and 83% which is similar to native cartilage extracellular matrix. The compressive strength of all the hydrogel composite scaffolds was found to be similar (∼32kPa) and suitable for cartilage tissue engineering applications. Besides, the hydrogel composite scaffold comprising 0.3% (w/v) genipin had the highest tan δ value (0.044) at a frequency of 1Hz which is around the walking frequency of a person. According to the in vitro analysis, this hydrogel composite scaffold did not show any cytotoxic effect on the rabbit mesenchymal stem cells and enabled cells to attach, proliferate and also migrate through the inner area of the scaffold. In conclusion, the produced hydrogel composite scaffold holds great promise for meniscus tissue engineering.

Comparison of Biological Features of Wild European Rabbit Mesenchymal Stem Cells Derived from Different Tissues

Although the European rabbit is an “endangered” species and a notorious biological model, the analysis and comparative characterization of new tissue sources of rabbit mesenchymal stem cells (rMSCs) have not been well addressed. Here, we report for the first time the isolation and characterization of rMSCs derived from an animal belonging to a natural rabbit population within the native region of the species. New rMSC lines were isolated from different tissues: oral mucosa (rOM-MSC), dermal skin (rDS-MSC), subcutaneous adipose tissue (rSCA-MSC), ovarian adipose tissue (rOA-MSC), oviduct (rO-MSC), and mammary gland (rMG-MSC). The six rMSC lines showed plastic adhesion with fibroblast-like morphology and were all shown to be positive for CD44 and CD29 expression (characteristic markers of MSCs), and negative for CD34 or CD45 expression. In terms of pluripotency features, all rMSC lines expressed NANOG, OCT4, and SOX2. Furthermore, all rMSC lines cultured under osteogenic, chondrogenic, and adipogenic conditions showed differentiation capacity. In conclusion, this study describes the isolation and characterization of new rabbit cell lines from different tissue origins, with a clear mesenchymal pattern. We show that rMSC do not exhibit differences in terms of morphological features, expression of the cell surface, and intracellular markers of pluripotency and in vitro differentiation capacities, attributable to their tissue of origin.

Tissue engineering and cell technologies: how these can help in correction of urinary system pathologies. Literature review and own experience

SummaryIntroduction. Modern possibilities of cellular and tissue engineering technologies are presented in this pub-lication, that are developed to be applied to urologic patholo gies in experimental and clinical practice. Оwn experience is described in rabbit bladder reconstruction with tissue engineering construction. Тissue engineering is one of the leading trends in modern science and envis-ages the development of restoration or replacement tech-niques for damaged structures with the use of scaffolds and cells. However, in spite of a huge number of publica-tions, urologic structures reconstructions are in minority. Nowadays, to treat damaged human tissues and organs, bioresorbable synthetic polimers are becoming more and more popular, those are used as the basis for cell culture (Ho M.H. et al., 2006; Shao J. et al., 2012). Foreign scien-tists have been successfully attempting to create tissue wall analogues for a long time. Маterials and methods.15 male Chinchilla rabbits underwent partial bladder resection with scaffold grafting containing smooth mio-cytes with urothelium, fibroblasts and mesenchymal stem cells, as well as acellular matrix. Results. In the group of animals that received scaffoled with labelled mesenchy-mal stem cells, in 5 out of 6 cases, matrix lysis occurred with no signs of graft rejection. After 2.5 months post-op, the capacity of the bladders was comparable with that pre-op. In the implantation site, one could visually see the area of a newly formed bladder wall, with vasculariza-tion signs. Histologically, initial stages of reparation and angiogenesis have been identified. Confocal microscopy of cryoslices from the implantation site showed labelled cells taking part in the urothelium-like structure forma-tion. In all cases when acellular matrix or scaffolds with smooth miocytes with urothelium and fibro blasts were implanted, graft rejection took place, with various de-grees of inflammation and decrease of bladder capacity. Conclusion. The use of tissue engineering construction made of composite matrix and rabbit mesenchymal stem cells was effective for small bladder defects reconstruc-tion. Further development of techniques to create mul-ticomponent graft with allogenic cells may improve the results of treating such pathologies in patients when au-togenic material cannot be harvested. A study is under way in St Petersburg Research Institute of Phthisiopulm-onology as of now, to study tissue engineered bladder augmentation, up to its total replacement (Russian Scien-tific Foundation grant no. 22-25-20167, https://rscf.ru/project/22-25-20167/ and St Petersburg Scientific Foun-dation grant in accordance with agreement dd. 14th April 2022 no. 20/2022)

Mussel-Inspired Carboxymethyl Chitosan Hydrogel Coating of Titanium Alloy with Antibacterial and Bioactive Properties.

Infection-related titanium implant failure rates remain exceedingly high in the clinic. Functional surface coating represents a very promising strategy to improve the antibacterial and bioactive properties of titanium alloy implants. Here, we describe a novel bioactive surface coating that consists of a mussel-inspired carboxymethyl chitosan hydrogel loaded with silver nanoparticles (AgNPs) to enhance the bioactive properties of the titanium alloy. The preparation of hydrogel is based on gallic acid grafted carboxymethyl chitosan (CMCS-GA) catalyzed by DMTMM (4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride). To build a firm bonding between the hydrogel and titanium alloy plate, a polydopamine layer was introduced onto the surface of the titanium alloy. With HRP/H2O2 catalysis, CMCS-GA can simply form a firm gel layer on the titanium alloy plate through the catechol groups. The surface properties of titanium alloy were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and water contact angle. Silver nanoparticles were loaded into the gel layer by in situ reduction to enhance the antibacterial properties. In vitro antibacterial and cell viability experiments showed that the AgNPs-loaded Ti-gel possesses excellent antibacterial properties and did not affect the proliferation of rabbit mesenchymal stem cells (MSCs).

Autophagy stimulation delayed biological aging and decreased cardiac differentiation in rabbit mesenchymal stem cells.

Introduction: Cardiovascular disease (CVD) is a type of disease that affects the function of cardiac-vascular tissues. This study aimed to consider the possible effects of autophagy, as an intrinsic catabolic pathway of cells, on the differentiation and aging process of mesenchymal stem cells (MSCs). Methods: In this study, bone marrow-derived MSCs were obtained from rabbit bone marrow aspirates. The stemness feature was confirmed by using flow cytometry analysis Cells at passage three were treated with 50 μM Metformin and 15μM hydroxychloroquine (HCQ) for 72 hours. The intracellular accumulation of autophagolysosomes was imaged using LysoTracker staining. Protein levels of autophagy (LC3II/I ratio), aging (Klotho, PARP-1, and Sirt-1) effectors, and cardiomyocyte-like phenotype (α-actinin) were studied by western blotting. Results: Based on our findings, flow cytometry analysis showed that the obtained cells expressed CD44 and CD133 strongly, and CD31 and CD34 dimly, showing a typical characteristic of MSCs. Our data confirmed an increased LC3II/I ratio in the metformin-received group compared to the untreated and HCQ-treated cells (P < 0.05). Besides, we showed that the incubation of rabbit MSCs with HCQ increased cellular aging by induction of PARP-1 while Metformin increased rejuvenating factor Sirt-1 comparing with the normal group (P < 0.05). Western blotting data showed that the autophagy stimulation response in rabbit MSCs postponed the biological aging and decreased the differentiation potential to the cardiac cells by diminishing α-actinin comparing with control cells (P < 0.05). Conclusion: In summary, for the informants in this study, it could be noted that autophagy inhibition/stimulation could alter rabbit MSCs aging and differentiation capacity.

Effects of Pulsed Electromagnetic Field Intensity on Mesenchymal Stem Cells

Introduction: Bone fractures remain a common injury. Nonunion fractures are often a serious complication where delays in tissue regeneration occur. The use of pulsed electromagnetic fields (PEMFs) for treatment has been studied for years, having reportedly been able to enhance bone regeneration. However, as various PEMF parameters can affect cellular properties differently, it is necessary to adjust each PEMF parameter to achieve the optimal regeneration. Methods: Primary rabbit mesenchymal stem cells (rMSCs) were cultured in vitro in two types of media, namely nondifferentiation and osteogenic differentiation media. The effect of various intensities of PEMF was assessed by evaluating properties such as cellular metabolism, proliferation, and osteogenic differentiation at different time points. Results: The findings suggest that PEMFs had no adverse effect on cellular morphology and mineralization. In contrast, increased metabolic activity was observed at higher PEMF intensity, whereas moderate PEMF intensities had the strongest effect on cell proliferation in both types of culture media. A comparison study was also done between the primary rMSCs against the MC3T3-E1 cells from a previously published article. It was shown that PEMFs improved cell metabolism of MSCs, while maintaining the metabolic activity of MC3T3. Conclusions: PEMFs generally improved cell proliferation for both cell types, whereas leaving cell mineralization unaffected. Taken together, it can be understood that the optimal application of PEMF stimulus, along with the right cell types, is indeed crucial in achieving effective bone regeneration in vitro.

Culture of rabbit bone marrow mesenchymal stem cells on polyurethane/pyrrole surface promoted differentiation into endothelial lineage.

Due to the electrical conductivity, pyrrole-based scaffolds are one of the attractive biomaterials in the regeneration of electrically active tissues like the heart and brain. Here, we investigated the impact of polyurethane/pyrrole scaffold on the angiogenesis differentiation of rabbit mesenchymal stem cells toward endothelial lineage in vitro. Nanoelectrospun polyurethane/pyrrole fibers were synthesized and characterized using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectrum analysis, scanning electron microscope (SEM) imaging. Mechanical properties, electroconductivity, and hydrophobicity were also measured. The viability of cells was monitored 72hours after being plated on the polyurethane/pyrrole surface. The endothelial differentiation of stem cells was explored using western blotting. ATR-FTIR revealed that the pyrrole was successfully polymerized to polypyrrole and blend with polyurethane fibers. The addition of pyrrole to polyurethane increased the tensile strength compared to the polyurethane group. These features coincided with the reduction of the hydrophilic properties of polyurethane. Based on our data, the electro-conductivity of polyurethane/pyrrole was superior compared to the polyurethane group. SEM imaging showed an appropriate cell attachment to the surface of polyurethane/pyrrole and polyurethane groups synthesized membranes. MTT assay revealed a significantly increased survival rate in the polyurethane/pyrrole group compared to the polyurethane group (P<.05). We noted a statistically significant increase of endothelial-associated proteins, CD31, von Willebrand factor, and CD34, in cells expanded on polyurethane/pyrrole compared to the polyurethane group (P<.05). As a more general note, it could be hypothesized that the polyurethane/pyrrole blend could improve the angiogenesis potency of rabbit bone marrow mesenchymal stem cells for regenerative purposes.

Study on Pipetting Motion Optimization of Automatic Spheroid Culture System for Spheroid Formation

This research group has established a technology for producing a three-dimensional cell constructed using only the cell itself. This technology uses a property in which the spheroids fuse with each other. We developed a system that automates the spheroid production process to obtain reproducible spheroids and suppress variation factors that occur from human operation. However, it has become clear that the dispersion occurs in the diameter depending on the number of cells of the spheroid even if the cells are handled in the same manner. The purpose of this research is to examine an appropriate pipetting motion in accordance with the number of cells of the spheroid to be produced. Rabbit mesenchymal stem cells (rMSCs) are used as the objects. The number of cells was set to 2×104, 3×104, and 4×104 cells/well, and the passage number as 7. The appearance of spheroids cultured using the motion programmed in accordance with each number of cells was observed every 24 hours for 5 days after seeding. The results of the analysis indicate that the optimum motion in each number of cells has been successfully specified, and reproducible spheroids have been successfully produced.

Preliminary studies of constructing a tissue-engineered lamellar corneal graft by culturing mesenchymal stem cells onto decellularized corneal matrix.

To construct a competent corneal lamellar substitute in order to alleviate the shortage of human corneal donor. Rabbit mesenchymal stem cells (MSCs) were isolated from bone marrow and identified by flow cytometric, osteogenic and adipogenic induction. Xenogenic decellularized corneal matrix (XDCM) was generated from dog corneas. MSCs were seeded and cultured on XDCM to construct the tissue-engineered cornea. Post-transplantation biocompatibility of engineered corneal graft were tested by animal experiment. Rabbits were divided into two groups then underwent lamellar keratoplasty (LK) with different corneal grafts: 1) XDCM group (n=5): XDCM; 2) XDCM-MSCs groups (n=4): tissue-engineered cornea made up with XDCM and MSCs. The ocular surface recovery procedure was observed while corneal transparency, neovascularization and epithelium defection were measured and compared. In vivo on focal exam was performed 3mo postoperatively. Rabbit MSCs were isolated and identified. Flow cytometry demonstrated isolated cells were CD90 positive and CD34, CD45 negative. Osteogenic and adipogenic induction verified their multipotent abilities. MSC-XDCM grafts were constructed and observed. In vivo transplantation showed the neovascularization in XDCM-MSC group was much less than that in XDCM group postoperatively. Post-transplant 3-month confocal test showed less nerve regeneration and bigger cell-absent area in XDCM-MSC group. This study present a novel corneal tissue-engineered graft that could reduce post-operatively neovascularization and remain transparency, meanwhile shows that co-transplantation of MSCs may help increase corneal transplantation successful rate and enlarge the source range of corneal substitute to overcome cornea donor shortage.

Sintered S53P4 bioactive glass scaffolds have anti-inflammatory properties and stimulate osteogenesis in vitro

Bioactive glasses (BAG) are used as bone-graft substitutes in orthopaedic surgery. A specific BAG scaffold was developed by sintering BAG-S53P4 granules. It is hypothesised that this scaffold can be used as a bone substitute to fill bone defects and induce a bioactive membrane (IM) around the defect site. Beyond providing the scaffold increased mechanical strength, that the initial inflammatory reaction and subsequent IM formation can be enhanced by coating the scaffolds with poly(DL-lactide-co-glycolide) (PLGA) is also hypothesised. To study the immunomodulatory effects, BAG-S53P4 (± PLGA) scaffolds were placed on monolayers of primary human macrophage cultures and the production of various pro- and anti-inflammatory cytokines was assessed using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and ELISA. To study the osteogenic effects, BAG-S53P4 (± PLGA) scaffolds were cultured with rabbit mesenchymal stem cells and osteogenic differentiation was evaluated by RT-qPCR and matrix mineralisation assays. The scaffold ion release was quantified and the BAG surface reactivity visualised. Furthermore, the pH of culture media was measured. BAG-S53P4 scaffolds had both anti-inflammatory and osteogenic properties that were likely attributable to alkalinisation of the media and ion release from the scaffold. pH change, ion release, and immunomodulatory properties of the scaffold could be modulated by the PLGA coating. Contrary to the hypothesis, the coating functioned by attenuating the BAG surface reactions and subsequent anti-inflammatory properties, rather than inducing an elevated inflammatory response compared to BAG-S53P4 alone. These results further validated the use of BAG-S53P4 (± PLGA) scaffolds as bone substitutes and indicate that scaffold properties can be tailored to a specific clinical need.

Comparing the chondrogenic potential of rabbit mesenchymal stem cells derived from the infrapatellar fat pad, periosteum & bone marrow.

Background & objectives:Rabbit model is commonly used to demonstrate the proof of concept in cartilage tissue engineering. However, limited studies have attempted to find an ideal source of rabbit mesenchymal stem cells (MSCs) for cartilage repair. This study aimed to compare the in vitro chondrogenic potential of rabbit MSCs isolated from three sources namely infrapatellar fat pad (IFP), periosteum (P) and bone marrow (BM).Methods:Rabbit MSCs from three sources were isolated and characterized using flow cytometry and multi-lineage differentiation assay. Cell proliferation was assessed using trypan blue dye exclusion test; in vitro chondrogenic potential was evaluated by histology and gene expression and the outcomes were compared amongst the three MSC sources.Results:MSCs from three sources shared similar morphology and expressed >99 per cent positive for CD44 and CD81 and <3 per cent positive for negative markers CD34, CD90 and human leukocyte antigen – DR isotype (HLA-DR). The BM-MSCs and IFP-MSCs showed significantly higher cell proliferation (P<0.001) than the P-MSCs from passage 4. Histologically, BM-MSCs formed a thicker cartilage pellet (P<0.01) with abundant matrix deposition than IFP and P-MSCs during chondrogenic differentiation. The collagen type 2 staining was significantly (P<0.05) higher in BM-MSCs than the other two sources. These outcomes were further confirmed by gene expression, where the BM-MSCs demonstrated significantly higher expression (P<0.01) of cartilage-specific markers (COL2A1, SOX9 and ACAN) with less hypertrophy.Interpretation & conclusions:This study demonstrated that BM-MSCs had superior chondrogenic potential and generated better cartilage than IFP and P-MSCs in rabbits. Thus, BM-MSCs remain a promising candidate for rabbit articular cartilage regeneration.

Irregular Bone Defect Repair Using Tissue-Engineered Periosteum in a Rabbit Model

Background:In previous studies, we succeeded in repairing a long bone defect with tissue-engineered periosteum (TEP), fabricated by incorporating rabbit mesenchymal stem cells with small intestinal submucosa. In this study, we investigated the feasibility of allogeneic irregular bone defect repair using TEP.Methods:We performed a subtotal resection of the scapula in 36 rabbits to establish a large irregular bone defect model. The rabbits were then randomly divided into three groups (n = 12 per group) and the defects were treated with TEP (Group 1), allogeneic deproteinized bone (DPB) (Group 2) or a hybrid of TEP and DPB (Group 3). At 4, 8, and 12 weeks after surgery, the rabbits were sacrificed, and the implants were harvested. X-ray radiographic and histological examinations were performed to detect bone healing. Ink-formaldehyde perfusion was introduced to qualitatively analyze vascularization in TEP engineered new bone.Results:The repair of scapular defects was diverse in all groups, shown by radiographic and histological tests. The radiographic scores in Group 1 and Group 3 were significantly higher than Group 2 at 8 and 12 weeks (p < 0.05). Histological scores further proved that Group 1 had significantly greater new bone formation compared to Group 3 (p < 0.05), while Group 2 had the lowest osteogenesis at all time-points (p < 0.001). Ink-formaldehyde perfusion revealed aboundant microvessels in TEP engineered new bone.Conclusion:We conclude that TEP is promising for the repair of large irregular bone defects. As a 3D scaffold, DPB could provide mechanical support and a shaping guide when combined with TEP. TEP engineered new bone has aboundant microvessels.

Pilot study on cardiogenic differentiation capability of rabbit mesenchymal stem cells

Cardiovascular diseases are still one of the most common reasons for mortality in humans. Mesenchymal stem cells (MSCs) are preferable in cardiac regeneration cell-based therapies because of their allogeneic and high proliferative potential. The electrophysiological properties of the rabbit heard is closer to human than the mouse. The current study aimed to trace mRNA expression changes of two stemness/cardiogenic differentiation ability-related transcriptionala factors OCT4 and GATA4 in rabbit MSCs during early stages of induced cardiomyocyte differentiation in vitro. The mesenchymal stem cell originated from different anatomical areas-subcutaneous, visceral, bone marrow and pericardial tissue. The cardiac differentiation protocol for mouse embryonic stem cells in hanging drop was adopted in rabbit MSCs. The best formed embryonal bodies (EBs) like structures were collected and cultivated on gelatin-coated plates. The total mRNA was obtained before cardiac differentiation and on the 6th day after it. SYBER based real-time PCR was performed to evaluate the mRNA expression fold-changes of OCT4 and GATA4. The cultivation of MSCs in hanging drops during cardiac differentiation induced EBs formation, without any contractile activity up to the 6th day of the differentiation in all cell types. The applied differentiation protocol significantly downregulated GATA4 expression in ADSCs - EBs, while in BMSCs, both target genes were significantly upregulated. In conclusion, the adopted cardiac differentiation protocol from mouse embryonic stem cells could be a useful approach for rabbit bone marrow mesenchymal stem cells. Since the rest of the cells revealed weak cardiogenic capability at this early stage, some modifications of induction protocols should be considered.

Electrical stimulation promotes the differentiation of rabbit mesenchymal stem cells toward chondrocytes

Electrical stimulation promotes the differentiation of rabbit mesenchymal stem cells toward chondrocytes