Basic Science
Effect of kartogenin-loaded gelatin methacryloyl hydrogel scaffold with bone marrow stimulation for enthesis healing in rotator cuff repair

https://doi.org/10.1016/j.jse.2020.06.013Get rights and content

Background

Strategies involving microfracture, biomaterials, growth factors, and chemical agents have been evaluated for improving enthesis healing. Kartogenin (KGN) promotes selective differentiation of bone marrow mesenchymal stem cells (BMSCs) into chondrocytes. Gelatin methacryloyl (GelMA) is a promising biomaterial for engineering scaffolds and drug carriers. Herein, we investigated KGN-loaded GelMA hydrogel scaffolds with a bone marrow–stimulating technique for the repair of rotator cuff tear.

Methods

KGN-loaded GelMA hydrogel scaffolds were obtained by ultraviolet GelMA crosslinking and vacuum freeze-drying. Fifty-four New Zealand rabbits were randomly divided into (1) repair only (control), (2) microfracture + repair (BMS), and (3) microfracture + repair augmentation with a KGN-loaded GelMA hydrogel scaffold (combined) groups. Tendons were repaired by transosseous sutures. The structure, degradation, and in vitro KGN release of the scaffolds were characterized. Animals were euthanized 4, 8, and 12 weeks after repair. Enthesis healing was evaluated by macroscopy, microcomputed tomography, histology, and biomechanical tests.

Results

The KGN-loaded GelMA hydrogel scaffolds are porous with a 60.4 ± 28.2-μm average pore size, and they degrade quickly in 2.5 units/mL collagenase solution. Nearly 81% of KGN was released into phosphate-buffered saline within 12 hours, whereas the remaining KGN was released in 7 days. Macroscopically, the repaired tendons were attached to the footprint. No differences were detected postoperatively in microcomputed tomography analysis among groups. Fibrous scar tissue was the main component at the tendon-to-bone interface in the control group. Disorderly arranged cartilage formation was observed at the tendon-to-bone interface in the BMS and combined groups 4 weeks after repair; the combined group exhibited relatively more cartilage. The combined group showed improved cartilage regeneration 8 and 12 weeks after repair. Similar results were found in tendon maturation scores. The ultimate load to failure and stiffness of the repaired tendon increased in all 3 groups. At 4 weeks after repair, the BMS and combined groups exhibited greater ultimate load to failure than the control group, although there was no difference in stiffness among groups. The BMS and combined groups exhibited greater ultimate load to failure and stiffness than the control group, and the combined group exhibited better values than the BMS group at 8 and 12 weeks after repair.

Conclusion

Compared with the bone marrow–stimulating technique, the KGN-loaded GelMA hydrogel scaffold with bone marrow stimulation improved enthesis healing by promoting fibrocartilage formation and improving the mechanical properties.

Section snippets

KGN-loaded GelMA hydrogel scaffold fabrication

Methacrylation of gelatin was performed using a previously reported method to obtain gelatin methacryloyl (GelMA).19 Briefly, 20 g of type A gelatin (Sigma-Aldrich, St Louis, MO, USA) was mixed at 20% (w/v) into phosphate-buffered saline (PBS) at 60°C and stirred until fully dissolved. Methacrylic anhydride (16 mL; Sigma-Aldrich) was added to the gelatin solution at a rate of 0.5 mL/min under stirred conditions at 50°C and allowed to react for 1 hour. Following a 5× dilution with Dulbecco's

Structural characterization and degradation of the KGN-loaded GelMA hydrogel scaffold

The KGN-loaded GelMA hydrogel scaffold scanning electron microscope images show that the scaffold has a porous network with an average pore size of 60.4 ± 28.2 μm (Fig. 1). It degraded slowly in PBS solution, and the degradation was approximately 48% on the 9th day and approximately 95% on the 18th day. When incubated in collagenase, the scaffold degraded quickly and was thoroughly degraded after 18 hours (Fig. 2).

In vitro KGN release from the KGN-loaded GelMA hydrogel scaffold

To determine KGN release in vitro, we performed a 7-day release test. KGN was

Discussion

This study investigated the effects of KGN-loaded GelMA hydrogel scaffolds with bone marrow stimulation on enthesis healing after RC repair in rabbits. The results of this study confirmed that KGN-loaded GelMA hydrogel scaffolds with bone marrow stimulation can enhance enthesis healing and promote better outcomes than bone marrow stimulation alone.

MSCs can differentiate into various musculoskeletal tissue types, including osteoblasts, fibroblasts, and chondrocytes, and secrete bioactive

Conclusions

The KGN-loaded GelMA hydrogel scaffolds with bone marrow stimulation improved enthesis healing, characterized by more fibrocartilage formation and improved mechanical properties. The scaffold could act as a bridge between the repaired tendon and bone bed and would be a suitable scaffold for the clinical enhancement of enthesis healing.

Disclaimer

The authors, their immediate families, and any research foundations with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.

References (30)

  • J.W. Nichol et al.

    Cell-laden microengineered gelatin methacrylate hydrogels

    Biomaterials

    (2010)
  • S. Tempelhof et al.

    Age-related prevalence of rotator cuff tears in asymptomatic shoulders

    J Shoulder Elbow Surg

    (1999)
  • K. Yue et al.

    Synthesis, properties, and biomedical applications of gelatin methacryloyl (GelMA) hydrogels

    Biomaterials

    (2015)
  • A. Boffa et al.

    Platelet-rich plasma augmentation to microfracture provides a limited benefit for the treatment of cartilage lesions: a meta-analysis

    Orthop J Sports Med

    (2020)
  • M. Girlovanu et al.

    Stem cells—biological update and cell therapy progress

    Clujul Med

    (2015)
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    The animal experiment in this study was approved by the Animal Care and Use Committee of Jiaxing University (JUMC2019-048).

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