OBJECTIVE: To evaluate the effect of biodegradable magnesium alloy materials in promoting tendon-bone healing during rotator cuff tear repair and to investigate their potential underlying biological mechanisms. METHODS: Forty-eight 8-week-old Sprague Dawley rats were taken and randomly divided into groups A, B, and C. Rotator cuff tear models were created and repaired using magnesium alloy sutures in group A and Vicryl Plus 4-0 absorbable sutures in group B, while only subcutaneous incisions and sutures were performed in group C. Organ samples of groups A and B were taken for HE staining at 1 and 2 weeks after operation to evaluate the safety of magnesium alloy, and specimens from the supraspinatus tendon and proximal humerus were harvested at 2, 4, 8, and 12 weeks after operation. The specimens were observed macroscopically at 4 and 12 weeks after operation. Biomechanical tests were performed at 4, 8, and 12 weeks to test the ultimate load and stiffness of the healing sites in groups A and B. At 2, 4, and 12 weeks, the specimens were subjected to the following tests: Micro-CT to evaluate the formation of bone tunnels in groups A and B, HE staining and Masson staining to observe the regeneration of fibrocartilage at the tendon-bone interface after decalcification and sectioning, and Goldner trichrome staining to evaluate the calcification. Immunohistochemical staining was performed to detect the expressions of angiogenic factors, including vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2), as well as osteogenic factors at the tendon-bone interface. Additionally, immunofluorescence staining was used to examine the expressions of Arginase 1 and Integrin beta-2 to assess M1 and M2 macrophage polarization at the tendon-bone interface. The role of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway in tendon-bone healing was further analyzed using real-time fluorescence quantitative PCR. RESULTS: Analysis of visceral sections revealed that magnesium ions released during the degradation of magnesium alloys did not cause significant toxic effects on organs such as the heart, liver, spleen, lungs, and kidneys, indicating good biosafety. Histological analysis further demonstrated that fibrocartilage regeneration at the tendon-bone interface in group A occurred earlier, and the amount of fibrocartilage was significantly greater compared to group B, suggesting a positive effect of magnesium alloy material on tendon-bone interface repair. Additionally, Micro-CT analysis results revealed that bone tunnel formation occurred more rapidly in group A compared to group B, further supporting the beneficial effect of magnesium alloy on bone healing. Biomechanical testing showed that the ultimate load in group A was consistently higher than in group B, and the stiffness of group A was also greater than that of group B at 4 weeks, indicating stronger tissue-carrying capacity following tendon-bone interface repair and highlighting the potential of magnesium alloy in enhancing tendon-bone healing. Immunohistochemical staining results indicated that the expressions of VEGF and BMP-2 were significantly upregulated during the early stages of healing, suggesting that magnesium alloy effectively promoted angiogenesis and bone formation, thereby accelerating the tendon-bone healing process. Immunofluorescence staining further revealed that magnesium ions exerted significant anti-inflammatory effects by regulating macrophage polarization, promoting their shift toward the M2 phenotype. Real-time fluorescence quantitative PCR results demonstrated that magnesium ions could facilitate tendon-bone healing by modulating the PI3K/AKT signaling pathway. CONCLUSION Biodegradable magnesium alloy material accelerated fibrocartilage regeneration and calcification at the tendon-bone interface in rat rotator cuff tear repair by regulating the PI3K/AKT signaling pathway, thereby significantly enhancing tendon-bone healing.
Animals ; Rotator Cuff Injuries/metabolism* ; Rats, Sprague-Dawley ; Signal Transduction ; Wound Healing/drug effects* ; Alloys/pharmacology* ; Rats ; Proto-Oncogene Proteins c-akt/metabolism* ; Rotator Cuff/metabolism* ; Macrophages/metabolism* ; Magnesium/pharmacology* ; Phosphatidylinositol 3-Kinases/metabolism* ; Vascular Endothelial Growth Factor A/metabolism* ; Male ; Biocompatible Materials ; Bone Morphogenetic Protein 2/metabolism*

Titanium alloy has good biological properties and is commonly used in orthopedics, but its bone integrity and antibacterial properties are poor, so surface modification is needed to make up for its shortcomings. Chitosan has good biocompatibility and film forming ability, and can be used as a carrier to introduce the target drug to the surface of titanium alloy, which can effectively improve the biological properties of titanium alloy materials and increase its application range. In this paper, the related research of chitosan surface modified titanium alloy materials in recent years is summarized. The modification methods of chitosan coating, the improvement of osteogenesisand antibacterial properties of titanium alloy materials are discussed in order to provide guidance for the clinical application of coating modification of titanium alloy materials.
Alloys ; Anti-Bacterial Agents/pharmacology* ; Chitosan ; Orthopedics ; Surface Properties ; Titanium

OBJECTIVE: We aimed to evaluate the efficacy and safety of a newly developed, partially retrievable flow-diverter (the FloWise) in an elastase-induced rabbit aneurysm model. MATERIALS AND METHODS: We developed a partially retrievable flow diverter composed of 48 strands of Nitinol and platinum wire. The FloWise is compatible with any microcatheter of 0.027-inch inner diameter, and is retrievable up to 70% deployment. The efficacy and safety of the FloWise were evaluated in the elastase-induced rabbit aneurysm model. The rate of technical success (full coverage of aneurysm neck) and assessment of aneurysm occlusion and stent patency was conducted by angiograms and histologic examinations at the 1-month, 3-month, and 6-month follow-up. The patency of small arterial branches (intercostal or lumbar arteries) covered by the FloWise were also assessed in the 5 subjects. RESULTS: We attempted FloWise insertion in a total of 32 aneurysm models. FloWise placement was successful in 31 subjects (96.9%). Two stents (6.2%) were occluded at the 3-month follow-up, but there was no evidence of in-stent stenosis in other subjects. All stented aneurysms showed progressive occlusion: grade I (complete aneurysm occlusion) in 44.4% and grade II (aneurysm occlusion > 90%) in 55.6% at 1 month; grade I in 90% and II in 10% at 3 months; and grade I in 90% and II in 10% at 6 months. All small arterial branches covered by the FloWise remained patent. CONCLUSION: A newly developed, partially retrievable flow-diverter seems to be a safe and effective tool of aneurysm occlusion, as evaluated in the rabbit aneurysm model.
Alloys ; Aneurysm/*chemically induced/radiography/*surgery ; Angiography ; Animals ; Arteries/pathology/surgery ; Catheters ; Cerebrovascular Circulation/physiology ; Constriction, Pathologic/chemically induced/radiography/surgery ; *Disease Models, Animal ; Humans ; Male ; Pancreatic Elastase/*pharmacology ; Platinum ; *Rabbits ; Stents/*adverse effects

BACKGROUNDWhether the low molecular weight heparin microcapsule coated occluder is helpful to endothelialization in atrial-septal defect models is uncertain. This study aimed to investigate the best conditions for low molecular weight heparin coated NiTi alloy occluder and provide the evidence of the efficacy and safety of atrial-septal defect occluders in vivo.

METHODSLow molecular weight heparin microcapsules were investigated using gelatin as microcapsule material. The prepared low molecular weight heparin gelatin particles were subjected to nickel and titanium alloy occluder coating by sodium hyaluronate. A dog model of atrial septal defects was established after treatment with low molecular weight heparin microcapsule coated occluder (n = 4) and uncoated occluder (n = 4). Endotheliocytes and fibroblastic cells in occluders were observed. And the rate of endothelialization was detected.

RESULTSWhen the concentration of gelatin was 1%, the diameters of particles were mostly about 100 microm, and the particle size was uniform. The envelope efficiency of low molecular weight heparin microcapsule was about 80%. The endothelialization of occluder in the model was more obvious in the coated group than in the uncoated group (P < 0.0001).

CONCLUSIONSLow molecular weight heparin can be prepared into microcapsules with their particle size in nanometric grade. The antithrombotic properties are kept in the nickel and titanium alloy occluder successfully coated with sodium hyaluronate. The endothelialization after the interventional occlusion in the coated group is obvious, indicating that low molecular weight heparin is helpful to the growth of endothelial cells in the occlude and the healing after the interventional occlusion.

Alloys ; chemistry ; Animals ; Anticoagulants ; pharmacology ; Capsules ; chemistry ; Disease Models, Animal ; Dogs ; Endothelial Cells ; drug effects ; ultrastructure ; Fibroblasts ; drug effects ; Gelatin ; chemistry ; Heart Septal Defects, Atrial ; drug therapy ; Heparin, Low-Molecular-Weight ; chemistry ; pharmacology ; Immunohistochemistry ; Microscopy, Electron, Transmission ; Particle Size ; Random Allocation

OBJECTIVEThe aim of the study is to improve the anticorrosive property of the dental FeCrMo soft magnetic alloy covered with TiN film obtained by ion beam assisted deposition (IBAD) technology in oral environment.

METHODSThe magnetic force of the FECrMo soft magnetic alloy after TiN film treated were measured by Instron test machine. An advanced electro-chemical method was used to measure the electric potential of corrosion (Ecorr), passive potential (Ep), passive current density (Ip), current density of corrosion (Icorr), polarization resistance (Rp), of FeCrMo soft magnetic alloy in simulated oral environment before and after surface modification.

RESULTSThere were no statistic changes of the magnetic force in 4 groups after alloy with TiN film treated. Comparing with the alloy without surface modified, the Ecorr, Rp of FeCrMo soft magnetic alloy was obviously higher, and the Icorr, Ip and Ep were obviously lower.

CONCLUSIONSThe anticorrosive property of the dental FeCrMo soft magnetic alloy with TiN film is better than that without modified.

Chromium Alloys ; Corrosion ; Dental Alloys ; Dental Prosthesis Retention ; Humans ; Magnetics ; Molybdenum ; Titanium ; pharmacology