Combination of graphene oxide and platelet-rich plasma improves tendon-bone healing in a rabbit model of supraspinatus tendon reconstruction

The treatment of rotator cuff tear is one of the major challenges for orthopedic surgeons.The key to treatment is the reconstruction of the tendon-bone interface(TBI).Autologous platelet-rich plasma(PRP)is used as a therapeutic agent to accelerate the healing of tendons,as it contains a variety of growth factors and is easy to prepare.Graphene oxide(GO)is known to improve the physical properties of biomaterials and promote tissue repair.In this study,PRP gels containing various concentrations of GO were prepared to promote TBI healing and supraspinatus tendon reconstruction in a rabbit model.The incorporation of GO improved the ultrastructure and mechanical properties of the PRP gels.The gels containing 0.5 mg/ml GO(0.5 GO/PRP)continuously released transforming growth factor-b1(TGF-b1)and platelet-derived growth factor(PDGF)-AB,and the released TGF-b1 and PDGF-AB were still at high concentrations,1063.451 pg/ml and814.217 pg/ml,respectively,on the 14th day.In vitro assays showed that the 0.5 GO/PRP gels had good biocompatibility and promoted bone marrow mesenchymal stem cells proliferation and osteogenic and chondrogenic differentiation.After 12 weeks of implantation,the magnetic resonance imaging,microcomputed tomography and histological results indicated that the newly regenerated tendons in the 0.5 GO/PRP group had a similar structure to natural tendons.Moreover,the biomechanical results showed that the newly formed tendons in the 0.5 GO/PRP group had better biomechanical properties compared to those in the other groups,and had more stable TBI tissue.Therefore,the combination of PRP and GO has the potential to be a powerful advancement in the treatment of rotator cuff injuries.

A Toarcian Ocean Anoxic Event record from an open-ocean setting in the eastern Tethys: Implications for global climatic change and regional environmental perturbation

The Early Toarcian“Oceanic Anoxic Event”(T-OAE)is recorded by marked disruption to both the climate system and marine ecosystems.Here,we present intergraded high-resolution carbon-isotope data(δ^(13)C),bulk geochemistry,mineral characterization from an open-ocean setting in the eastern Tethys.With these data,we(1)construct the high-resolution record of the T-OAE from an open-ocean setting in the eastern Tethys;(2)show that the T-OAE in the Sewa succession was marked by coarser-grained deposits associated with high-energy conditions within the otherwise low-energy claystone deposits that likely linked to a globally increased supply of clastic sediments into marginal and deeper marine basin;(3)propose that the low C_(org):P_(total) ratios,in combination with bioturbated structure and depletion or slight enrichment in redox-sensitive trace elements of V,Mo,and U suggest a long-term oxygenation event throughout the T-OAE interval at the Sewa succession,and hence,anoxia may not play a fundamental role during the Toarcian negative CIE in this setting;(4)exhibit that a warming and more humid climate began at the start of the T-OAE,and many episodic changes in sediment provenance throughout the T-OAE interval occurred at this location;and(5)suggest that accumulation of organic-matter sediments during the T-OAE is generally controlled by global climatic changes,but a regional environmental perturbation also might influence the preservation of organic matter.