Objective To investigate the improvement effects and mechanisms of composite chitosan (CS) hydrogel on traditional polypropylene (PP) mesh for repairing abdominal wall defects. Methods CS hydrogel was prepared via physical cross-linking and then combined with PP mesh to create a CS hydrogel/PP mesh composite. The internal structure and hydrophilicity of the composite were characterized using macroscopic observation, upright metallographic microscope, scanning electron microscopy, and water contact angle measurements. The performance of the composite (experimental group) in resisting cell adhesion and supporting cell infiltration was assessed through fibroblast (NIH-3T3) infiltration experiments and human umbilical vein endothelial cells (HUVECs) tube formation assays, and simple cells were used as control group. Finally, a bilateral abdominal wall defect model (1.5 cm×1.0 cm) was established in 18 Sprague Dawley rats aged 8-10 weeks, with the composite used on one side (experimental group) and PP mesh on the other side (control group). The effects on promoting wound healing, preventing adhesion, angiogenesis, and anti-inflammation were investigated through macroscopic observation, histological staining (HE and Masson staining), and immunohistochemical staining (CD31, CD68). Results The composite appeared as a pale yellow, transparent solid with a thickness of 2-3 mm, with the PP mesh securely encapsulated within the hydrogel. Scanning electron microscopy revealed that the hydrogel contained interconnected pores measuring 100-300 μm, forming a porous structure. Contact angle measurements indicated that CS hydrogel exhibited good hydrophilicity, while PP mesh was highly hydrophobic. In vitro cell culture experiments showed that DAPI staining indicated fewer positive cells in the experimental group after 1 day of culture, while the cells in control group covered the entire well plate. After 3 days of culture, the cells in experimental group were spherical and displayed uneven fluorescence, suggesting that the material could reduce cell adhesion while supporting cell infiltration. HUVECs tube formation experiments demonstrated an increase in cell numbers in experimental group with a trend towards tube formation, while cells in control group were sparsely distributed and showed no migration. In the rat abdominal wall defect repair experiment, results showed that after 1 week post-surgery, the experimental group had tissue and blood vessels infiltrating, and by 4 weeks, the integrity was well restored with significant regeneration of muscle and blood vessels, while the control group exhibited adhesions and incomplete healing. HE staining results indicated weaker cell infiltration in the experimental group, with cell density significantly higher than that of the control group at 2 and 4 weeks post-surgery (P<0.05). Masson staining revealed that collagen fibers in the experimental group were arranged neatly, with significantly increased collagen content at 2 weeks post-surgery (P<0.05), while collagen content was similar in both groups at 4 weeks (P>0.05). Immunohistochemical staining showed that CD31-positive cells were evenly distributed between muscle layers in the experimental group, whereas the control group exhibited notable defects. At 2 weeks after operation, the CD31-positive cell ratio was significantly higher than that in the control group (P<0.05); at 2 and 4 weeks after operation, the CD68-positive cell ratio in the experimental group was significantly lower than that in the control group (P<0.05). Conclusion CS hydrogel has a positive effect on preventing adhesions and promoting wound healing, exhibiting anti-inflammatory and pro-angiogenic properties during the healing process. This provides a promising strategy to address challenges related to abdominal adhesions and reconstruction.
We investigated the development of an injectable, biodegradable hydrogel composite of poly(trimethylene carbonate)-F127-poly(trimethylene carbonate)(PTMC11-F127-PTMC11)loaded with bone morphogenetic protein-2 (BMP-2) derived peptide P24 for ectopic bone formation in vivo and evaluated its release kinetics in vitro. Then we evaluated P24 peptide release kinetics from different concentration of PTMC11-F127-PTMC11 hydrogel in vitro using bicinchoninic acid (BCA)assay. P24/PTMC11-F127-PTMC11 hydrogel was implanted into each rat's erector muscle of spine and ectopic bone formation of the implanted gel in vivo was detected by hematoxylin and eosin stain (HE). PTMC11-F127-PTMC11 hydrogel with concentration more than 20 percent showed sustained slow release for one month after the initial burst release. Bone trabeculae surround the P24/PTMC11-F127-PTMC11 hydrogel was shown at the end of six weeks by hematoxylin and eosin stain. These results indicated that encapsulated bone morphogenetic protein (BMP-2) derived peptide P24 remained viable in vivo, thus suggesting the potential of PTMC11-F127-PTMC11 composite hydrogels as part of a novel strategy for localized delivery of bioactive molecules.
ObjectiveTo review the methods of improving the mechanical properties of hydrogels and the research progress in bone tissue engineering. MethodsThe recent domestic and foreign literature on hydrogels in bone tissue engineering was reviewed, and the methods of improving the mechanical properties of hydrogels and the effect of bone repair in vivo and in vitro were summarized. ResultsHydrogels are widely used in bone tissue engineering, but their mechanical properties are poor. Improving the mechanical properties of hydrogels can enhance bone repair. The methods of improving the mechanical properties of hydrogels include the construction of dual network structures, inorganic nanoparticle composites, introduction of conductive materials, and fiber network reinforcement. These methods can improve the mechanical properties of hydrogels to various degrees while also demonstrating a significant bone repair impact. ConclusionThe mechanical properties of hydrogels can be effectively improved by modifying the system, components, and fiber structure, and bone repair can be effectively promoted.
Acute kidney injury is a worldwide public health issue, and its treatment and management strategies continue to advance. In addition to traditional kidney replacement therapy, research in recent years has been focused on whole organ engineering and biofabrication of kidney assistive devices and bioinjections for in-body regeneration. Hydrogel materials show great potential in renal tissue engineering because of their good biocompatibility, thermal stability and controllable biochemical and mechanical properties. This article reviews the application of various hydrogel materials in renal tissue engineering to promote kidney regeneration and discusses the characteristics and applications of natural hydrogels and synthetic hydrogels, which is expected to further promote their clinical applications.
Spinal cord injury (SCI) is a complex pathological process. Based on the encouraging results of preclinical experiments, some stem cell therapies have been translated into clinical practice. Mesenchymal stem cells (MSCs) have become one of the most important seed cells in the treatment of SCI due to their abundant sources, strong proliferation ability and low immunogenicity. However, the survival rate of MSCs transplanted to spinal cord injury is rather low, which hinders its further clinical application. In recent years, hydrogel materials have been widely used in tissue engineering because of their good biocompatibility and biodegradability. The treatment strategy of hydrogel combined with MSCs has made some progress in SCI repair. This review discusses the significance and the existing problems of MSCs in the repair of SCI. It also describes the research progress of hydrogel combined with MSCs in repairing SCI, and prospects its application in clinical research, aiming at providing reference and new ideas for future SCI treatment.
ObjectiveTo study the ectopic osteogenesis and biocompatibility of bone morphogenetic protein 2 (BMP-2)-derived peptide P24 loaded chitosan-4-thio-butylamidine (CS-TBA) hydrogel.MethodsFirst, the CS-TBA/hydroxyapatite (HA) solution was prepared by using chitosan, 2-iminothiolane hydrochloride, and HA. Then, the different amount of P24 peptides were added to the CS-TBA/HA to prepare the CS-TBA/5%P24/HA and CS-TBA/10%P24/HA solutions. Finally, β-glycerophosphate disodium (β-GP) was added to the CS-TBA/HA, CS-TBA/5%P24/HA, and CS-TBA/10%P24/HA to prepare the CS-TBA/HA/β-GP, CS-TBA/5%P24/HA/β-GP, and CS-TBA/10%P24/HA/β-GP hydrogels, respectively. Eighteen Sprague Dawley female rats were randomly divided into 3 groups (n=6), which were injected into the back muscle pouches with equal volume CS-TBA/HA/β-GP hydrogel (group A), CS-TBA/5%P24/HA/β-GP hydrogel (group B), and CS-TBA/10%P24/HA/β-GP hydrogel (group C). The animals were sacrificed at 4 and 8 weeks and conducted micro-CT. The ability of biodegradation and osteogenesis of hydrogl was detected by trabecular thickness (Tb.Th), trabecular number (Tb.N), bone mineral density (BMD), and histological staining (HE and Masson).ResultsAll the rats survived to the time point of the harvest. Micro-CT results showed that the new bones gradually increased in each group after operation. At the same time, the new bone formation was more obvious in groups B and C than in group A, and with the increase of P24 concentration, new bone formation in group C was much more than that in group B. The Tb.Th, Tb.N, and BMD increased gradually in 3 groups, and the differences between 4 and 8 weeks were significant (P<0.05) except the Tb.Th in group A. At different time points, the Tb.Th, Tb.N, and BMD were significantly higher in groups B and C than in group A (P<0.05), and in group C was higher than in group B (P<0.05), showing significant differences between groups. Histological staining showed that the materials of groups B and C were biodegradable, and the osteogenic effect was increased with the increase of P24 concentration.ConclusionP24 peptide can improve the ectopic osteogenesis of CS-TBA hydrogel, and the 10% concentration is more effective.
Objective To investigate the application potential of alginate-strontium (Sr) hydrogel as an injectable scaffold material in bone tissue engineering. Methods The alginate-Sr/-calcium (Ca) hydrogel beads were fabricated by adding 2.0wt% alginate sodium to 0.2 mol/L SrCl2/CaCl2 solution dropwise. Microstructure, modulus of compression, swelling rate, and degradability of alginate-Sr/-Ca hydrogels were tested. Bone marrow mesenchymal stem cells (BMSCs) were isolated from femoral bones of rabbits by flushing of marrow cavity. BMSCs at passage 5 were seeded onto the alginate-Sr hydrogel (experimental group) and alginate-Ca hydrogel (control group), and the viability and proliferation of BMSCs in 2 alginate hydrogels were assessed. The osteogenic differentiation of cells embeded in 2 alginate hydrogels was evaluated by alkaline phosphate (ALP) activity, osteoblast specific gene [Osterix (OSX), collagen type I, and Runx2] expression level and calcium deposition by fluorescent quantitative RT-PCR and alizarin red staining, Von Kossa staining. The BMSCs which were embeded in alginate-Ca hydrogel and cultured with common growth medium were harvested as blank control group. Results The micromorphology of alginate-Sr hydrogel was similar to that of the alginate-Ca hydrogel, with homogeneous pore structure; the modulus of compression of alginate-Sr hydrogel and alginate-Ca hydrogel was (186.53 ± 8.37) and (152.14 ± 7.45) kPa respectively, showing significant difference (t=6.853, P=0.002); there was no significant difference (t=0.737, P=0.502) in swelling rate between alginate-Sr hydrogel (14.32% ± 1.53%) and alginate-Ca hydrogel (15.25% ± 1.64%). The degradabilities of 2 alginate hydrogels were good; the degradation rate of alginate-Sr hydrogel was significantly lower than that of alginate-Ca hydrogel on the 20th, 25th, and 30th days (P lt; 0.05). At 1-4 days, the morphology of cells on 2 alginate hydrogels was spherical and then the shape was spindle or stellate. When three-dimensional cultured for 21 days, the DNA content of BMSCs in experimental group [(4.38 ± 0.24) g] was significantly higher than that in control group [(3.25 ± 0.21) g ] (t=8.108, P=0.001). On the 12th day after osteogenic differentiation, the ALP activity in experimental group was (15.28 ± 1.26) U/L, which was significantly higher than that in control group [(12.07 ± 1.12) U/L] (P lt; 0.05). Likewise, the mRNA expressions of OSX, collagen type I, and Runx2 in experimental group were significantly higher than those in control group (P lt; 0.05). On the 21th day after osteogenic differentiation, alizarin red staining and Von Kossa staining showed calcium deposition in 2 groups; the calcium nodules and phosphate deposition in experimental group were significantly higher than those in control group (P lt; 0.05). Conclusion Alginate-Sr hydrogel has good physicochemical properties and can promote the proliferation and osteogenic differentiation of BMSCs, so it is an excellent injectable scaffold material for bone tissue engineering.
Objective To investigate the effect of porcine small intestinal submucosa extracellular matrix (PSISM) on the vitality and gene regulation of hepatocyte so as to lay the experimental foundation for the application of PSISM in liver tissue engineering. Methods The experiment was divided into two parts: ① BRL cells were cultured with 50, 100, and 200 μg/mL PSISM-medium which were prepared by adding PSISM into the H-DMEM-medium containing 10%FBS in groups A1, B1, and C1, and simple H-DMEM-medium served as a control (group D1); ② BRL cells were seeded on 1%, 2%, and 3% PSISM hydrogel which were prepared by dissolving PSISM in sterile PBS solution containing 0.1 mol/L NaOH in groups A2, B2, and C2, and collagen type I gel served as a control (group D2). At 1, 3, and 5 days after culture, the morphology and survival of liver cells were detected by the Live/Dead fluorescent staining. The cell vitality was tested by cell counting kit-8 (CCK-8) assay. And the relative expressions of albumin (ALB), cytokeratin 18 (CK18), and alpha-fetoprotein (AFP) in hepatocytes were determined by real-time fluorescent quantitative PCR (RT-qPCR). Results The Live/Dead fluorescent staining showed the cells survived well in all groups. CCK-8 results displayed that the absorbance (A) value of group C1 was significantly higher than that of group D1 at 5 days after culture with PSISM-medium, and there was no significant difference between groups at other time points (P>0.05). After cultured with PSISM hydrogels, theA values of groups A2, B2, and C2 were significantly higher than those of group D2 at 3 and 5 days (P<0.05), theA value of group A2 was significantly higher than that of groups B2 and C2 at 5 days (P<0.05), but there was no significant difference between groups at other time points (P>0.05). RT-qPCR showed that the relative expressions of ALB and CK18 mRNA significantly increased and the relative expression of AFP mRNA significantly decreased in groups A1, B1, and C1 when compared with group D1 (P<0.05). The relative expression of CK18 mRNA in group C1 was significantly lower than that in groups A1 and B1 (P<0.05). The relative expressions of ALB and CK18 mRNA were significantly higher and the relative expression of AFP mRNA was significantly lower in groups A2, B2, and C2 than group D2 (P<0.05); the relative expression of CK18 mRNA in group A2 was significantly higher than that in group B2 (P<0.05), and the relative expression of AFP mRNA in group A2 was significantly lower than that in group C2 (P<0.05), but no significant difference was found between other groups (P>0.05). Conclusion PSISM has good compatibility with hepatocyte and can promote the vitality and functional gene expression of hepatocyte. PSISM is expected to be used as culture medium supplement or cell carrier for liver tissue engineering.
Objective To investigate the therapeutic effect of BMSCs- chitosan hydrogel complex transplantation on intervertebral disc degeneration and to provide experimental basis for its cl inical appl ication. Methods Two mill il iter of bone marrow from 6 healthy one-month-old New Zealand rabbits were selected to isolate and culture BMSCs. Then, BMSCs at passage 3 were labeled by 5-BrdU and mixed with chitosan hydrogel to prepare BMSCs- chitosan hydrogel complex. Six rabbitswere selected to establ ish the model of intervertebral disc degeneration and randomized into 3 groups (n=2 per group): control group in which intervertebral disc was separated and exposed but without further processing; transplantation group in which 30 μL of autogenous BMSCs- chitosan hydrogel complex was injected into the center of defected intervertebral disc; degeneration group in which only 30 μL of 0.01 mol/L PBS solution was injected. Animals were killed 4 weeks later and the repaired discs were obtained. Then cell 5-BrdU label ing detection, HE staining, aggrecan safranin O staining, Col II immunohistochemical staining and gray value detection were conducted. Results Cell label ing detection showed that autogenous BMSCs survived and prol iferated after transplantation, forming cell clone. HE staining showed that in the control and transplantation groups, the intervertebral disc had a clear structure, a distinct boundary between the central nucleus pulposus and the outer anulus fibrosus, and the obviously stained cell nuclear and cytochylema; while the intervertebral disc in the degeneration group had a deranged structure and an indistinct division between the nucleus pulposus and the outer anulus fibrosus. Aggrecan safarine O stainning notified that intervertebral disc in the control and transplantation groups were stained obviously, with a clear structure; while the intervertebral disc in the degeneration group demonstrated a deranged structure with an indistinct division between the nucleus pulposus and the anulus fibrosus. Col II immunohistochemical staining showed that the tawny-stained region in the control group was located primarily in the central nucleus pulposus with a clear structure of intervertebral disc, the central nucleus pulposus in the transplantation group was positive with obvious tawny-stained intercellular substances and a complete gross structure, while the stained color in the degeneration group was l ighter than that of other two groups, with a indistinct structure.Gray value assay of Col II immunohistochemical staining section showed that the gray value of the control, the ransplantation and the degeneration group was 223.84 ± 3.93, 221.03 ± 3.53 and 172.50 ± 3.13, respectively, indicating there was no significant difference between the control and the transplantation group (P gt; 0.05), but a significant difference between the control and transplantation groups and the degeneration group (P lt; 0.05). Conclusion The rabbit BMSCs-chitosan hydrogel complex can repair intervertebral disc degeneration, providing an experimental foundation for the cl inical appl ication of injectable tissue engineered nucleus pulposus complex to treat intervertebral disc degeneration.
Objective To study the effect of sodium hyaluronate hydrogel in treating residual cavity on body surface after abscess drainage so as to provide new method to speed up the heal ing of residual cavity after body surface abscess drainageand reduce the frequency of dressing change and cl inic nursing workload. Methods From June 2007 to March 2008, 60 outpatients with body surface abscess drainage were randomly divided into hydrogel group (group A, 30 cases) and the control group (group B, 30 cases). In group A, there were 16 males and 14 females aged (49.5 ± 6.1) years, the disease course was (3.8 ± 0.6) days, and the volume of residual cavity was (4.19 ± 1.31) mL. In group B, there were 18 males and 12 females aged (50.2 ± 7.6) years, the disease course was (4.3 ± 0.5) days, and the volume of residual cavity was (4.04 ± 1.22) mL. There was no significant difference between two groups in gender, age, disease course and volume of residual cavity (P gt; 0.05). Residual cavity was smeared with 1 mL/cm2 sodium hyaluronate hydrogel in group A and drained by sal ine gauze in group B, the dressing was changed every two to three days. Residual cavity volume was recorded every four days, and the residual cavity volume, the frequency of out-patient dressing and the heal ing time residual of cavity were compared. Results The volume of residual cavity was (3.11 ± 1.12), (1.75 ± 0.95) and (0.55 ± 0.56) mL in group A, and was (3.39 ± 1.12), (2.64 ± 0.99) and (1.81 ± 0.81) mL in group B at 4, 8 and 12 days after treatment respectively, showing no significant differences at 4 days (P gt; 0. 05), but significant difference at 8 and 12 days (P lt; 0.01). Residual cavity heal ing time was (12.70 ± 2.78) days in group A and (20.27 ± 3.89) days in group B, and the frequency of dressing change was 5.53 ± 1.33 in group A and 9.13 ± 1.81 in group B, indicating significant differences between two groups (P lt; 0.01). Conclusion Sodium hyaluronate hydrogel can promote residual cavity heal ing, reduce the frequency of dressing change of out-patient and decrease the cl inic nursing care workload.