ABSTRACT
KLD-12 peptide with a sequence of AcN-KLDLKLDLKLDL-CNH2 was synthesized and its biocompatibility was assessed in animals.Rabbit MSCs were cultured in the hydrogel for 2 weeks.Live cells were counted by using Caicein-AM/PI fluorescence staining.MTT was employed to assess the viability of MSCs cultured in KLD-12 peptide solution of 0.01%,0.03%,and 0.05%.Hemolysis test,skin irritation test and implantation test were conducted to evaluate its biocompatibility with host tissues.Our results demonstrated that the MSCs in hydrogel grew well and maintained round shape.Cell survival rate was 92.15%(mean: 92.15%±1.17%)at the 7th day and there was no difference in survival rate between day 7 and day 14.Cell proliferation test showed that the A value of the KLD-12solutions was not significantly different from that of control groups(complete culture media)(P>0.05)at the 24th and 48th h.The hemolysis rate of KLD-12 solution was 0.112%.Skin irritation test showed that the skin injected with KLD-12 solution remained normal and the score of skin irritation was 0.The histological examination with HE staining exhibited that the skin layers were clear and there was no infiltration with neutrophilic granulocytes and lymphocytes.It is concluded that KLD-12 peptide hydrogel had a good biocompatibility with host rabbit and MSCs,and KLD-12 peptide hydrogel can provide an appropriate microenvironment for MSCs.
ABSTRACT
This study examined the effect of IKVAV peptide nanofiber on proliferation,adhesion and differentiation into neurocytes of bone marrow stromal cells(BMSCs).IKVAV Peptide-amphiphile was synthesized and purified.Then,hydrogen chloride was added to the diluted aqueous solutions of PA to induce spontaneous formation of nanofiber in vitro.The resultant samples was observed under transmission electron microscope.BMSCs were cultured with IKVAV peptide nanofiber.The effect of IKVAV nanofiber on the proliferation,adhesion and induction differentiation of BMSCs was observed by inverted microscopy,calcein-AM/PI staining,cell counting and immunofluorescence staining.The results demonstrated that IKVAV peptide-amphiphile could self-assemble to form nanofiber gel.BMSCs cultured in combination with IKVAV peptide nanofiber gel grew well and the percentage of live cells was over 90%.IKVAV peptide nanofiber gel exerted no influence on the proliferation of BMSCs and could promote the adhesion of BMSCs and raise the ratio of neurons when BMSCs were induced to differentiate into neurocytes.It is concluded that BMSCs could proliferate and adhere well and yield more neurons during when induced to differente into neurocytes on IKVAV peptide nanofiber gel.
ABSTRACT
The mobilization efficiency of granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) to bone marrow mononuclear cells (MNCs) in mice was observed,and the changes of CXCL12/CXCR4 signal were detected in order to find out the mobilization mechanism of stem cells.Kunming mice were randomly divided into two groups.The mice in treatment group were subjected to subcutaneous injection of G-CSF at a dose of 100 μg/kg and SCF at a dose of 25 μg/kg every day for 5 days,and those in control group were given isodose physiological saline.The MNCs were separated,counted and cultured,and the colony-forming unit-fibroblast (CFU-F) was evaluated.CD34+CXCR4+ MNCs were sorted by flow cytometry.The expression of CXCL12 protein in bone marrow extracellular fluid was detected by ELISA,and that of CXCL12 mRNA in bone marrow was measured by RT-PCR.The results showed that the counts of MNCs in peripheral blood and bone marrow were increased after administration of G-CSF/SCF (P＜0.01).The factors had a dramatic effect on the expansion capability of CFU-F (P＜0.05).Flow cytometric of bone marrow MNCs surface markers revealed that CD34+CXCR4+ cells accounted for 44.6%±8.7% of the total CD34+ MNCs.Moreover,G-CSF/SCF treatment induced a decrease in bone marrowCXCL12 mRNA that closely mirrored the fall in CXCL12 protein.In this study,it is evidenced that G-CSF/SCF can effectively induce MNCs mobilization by disrupting the balance of CXCL12/CXCR4 signaling pathway in the bone marrow and down-regulating the interaction of CXCL12/CXCR4.
ABSTRACT
In order to improve the surface properties of PLGA polymer for a better material/cell in-terface to modulate the cells behaviors, we prepared a novel three-block copolymer, PLGA-[ASP-PEG],and immobilized an RGD-containing peptide, Gly-Arg-Gly-Asp-Ser-Pro-Cys (GRGDSPC) on the sur-face of it. Transforming growth factor-131 (TGF-β1) was transfected into bone marrow stromal cells (MSCs) employed as seeded cells. Cell adhesion, spreading, proliferation and differentiation on this material were investigated. The results showed that the cell adhesive ratio on RGD-modified materials was higher than on un-modified materials (P<0.05). The extent of cell spreading was also wider on RGD-modified materials than on un-modified materials. Cell proliferation indices of transfected MSCs were increased as compared with the un-transfected MSCs (P<0.05). The ALP activities in the MSCs cultured with RGD-modified materials were higher than on un-modified materials after 14 days (P<0.05), and those in transfected MSCs were higher than in un-transfected MSCs (P<0.05). It was suggested that the combined use of RGD-modification and TGF-β gene transfection could improve the interaction of biomaterial and cells.
ABSTRACT
g revealed nestin (+) or NF (+), and GFAP (-). It was concluded that hMSCs were successfully cultured and induced to differentiate into neuron-like cells.
ABSTRACT
In this study, the bioactivity of a novel BMP2-derived oligopeptide P24 was investigated by using the model of rabbit femoral defect after loaded in the biodegradable poly (lactic acid / glycolic acid / asparagic acid-co-polyethylene glycol) (PLGA-[ASP-PEG]). A 1.5-cm unilateral segmental bone defect was created in the left femoral diaphysis in each of the 30 new zealand white rabbits.The defects of 18 legs filled with BMP2-derived peptide P24 combined with PLGA-[ASP-PEG]scaffold serves as the experimental group, and the defects in the rest 12 rabbits filled with(PLGA-[ASP-PEG]) without P24 as control group. The bone-repairing capability in the target region of the two group was grossly, radiologically, histopathologically and biomechanically evaluated 4, 8and 12 weeks after the operation. Our results showed that in each group, primary healing of incision was achieved in the two groups. Radiographically, in experimental group, defects were filled with induced callus within 8 weeks, and a cortical bone-like structure was observed in some animals at the12th week. According to the standardized stage of bone defect repair, 9 (64.28%) achieved grade-4healing. In contrast, little bone formation was seen in the defects even 12 weeks after the operation,and 5 (62.50%) had grade 0 healing in this group. Histologically, tissue engineering material was mostly absorbed and cartilage was found around implants in the experimental group at the 4th week;8 weeks after operation, the engineering material was completely absorbed, and formation of woven bone was observed and typical trabecular bone structure could be seen. In control group, 8 weeks after operation, the defect was filled with fibrous tissues, and no bone-like structure was observed. Statistical analysis showed very significant difference in biomechanical indicators between the two groups (P＜0.05). It is concluded that new oligopeptide P24 can induce excellent bone regeneration and promote bone repair.