The rat as a novel model for chronic rotator cuff injuries.

Chronic rotator cuff injuries (CRCIs) still present a great challenge for orthopaedics surgeons. Many new therapeutic strategies are developed to facilitate repair and improve the healing process. However, there is no reliable animal model for chronic rotator cuff injury research. To present a new valuable rat model for future chronic rotator cuff injuries (CRCIs) repair studies, and describe the changes of CRCIs on the perspectives of histology, behavior and MRI. Sixty male Wistar rats were enrolled and underwent surgery of the left shoulder joint for persistent subacromial impingement. They were randomly divided into experimental group (n = 30, a 3D printed PEEK implant shuttled into the lower surface of the acromion) and sham operation group (n = 30, insert the same implant, but remove it immediately). Analyses of histology, behavior, MRI and inflammatory pain-related genes expression profiles were performed to evaluate the changes of CRCIs. After 2-weeks running, the rats in the experimental group exhibited compensatory gait patterns to protect the injured forelimb from loading after 2-weeks running. After 8-weeks running, the rats in the experimental group showed obvious CRCIs pathological changes: (1) acromion bone hyperplasia and thickening of the cortical bone; (2) supraspinatus muscle tendon of the humeral head: the bursal-side tendon was torn and layered with disordered structure, forming obvious gaps; the humeral-side tendon is partially broken, and has a neatly arranged collagen. Partial fat infiltration is found. The coronal T2-weighted images showed that abnormal tendon-to-bone junctions of the supraspinatus tendon. The signal intensity and continuity were destroyed with contracted tendon. At the nighttime, compared with the sham operation group, the expression level of IL-1ß and COX-2 increased significantly (P = 0063, 0.0005) in the experimental group. The expression of COX-2 in experimental group is up-regulated about 1.5 times than that of daytime (P = 0.0011), but the expression of IL-1ß, TNF-a, and NGF are all down-regulated (P = 0.0146, 0.0232, 0.0161). This novel rat model of chronic rotator cuff injuries has the similar characteristics with that of human shoulders. And it supplies a cost-effective, reliable animal model for advanced tissue engineered strategies and future therapeutic strategies.

Effects of Tourniquet Application on Faster Recovery after Surgery and Ischemia-Reperfusion Post-Total Knee Arthroplasty, Cementation through Closure versus Full-Course and Nontourniquet Group.

Pneumatic tourniquets are used in total knee arthroplasty (TKA) for surgical field visualization and improved cementation; however, their use is controversial. This study aimed to assess the effects of tourniquet application on faster recovery post-TKA. Our hypothesis was that inflammation and limb function would be similar with different tourniquet applications. A prospective randomized double-blinded trial assessed tourniquets effects on postoperative pain, swelling, and early outcome in TKA. In present study, 50 TKAs were enrolled in each group as follows: full course (FC), cementation through closure (CTC), and no tourniquet (NT), CTC as treatment group while FC and NT as control groups. Topical blood samples of 3 mL from the joint cavity and drainage bags were obtained at special time point. At last, all samples such as tumor necrosis factor-a (TNF-a), C-C motif chemokine ligand 2 (CCL2), pentraxin 3 (PTX3), prostaglandin E2 (PGE2), superoxide dismutase 1 (SOD1), and myoglobin (Mb) were detected by ELISA. Active and passive range of motion (ROM) values, pain score by the visual analog scale (VAS), change of thigh circumference were recorded at special time point as well. In topical blood, the change of inflammatory factors, such as TNF-a, PTX3, CCL2, PGE2, SOD1, and Mb, was lower in CTC and NT groups than in FC group (p < 0.01 and 0.05). Although VAS and ROM were comparable preoperatively in three groups (p > 0.05), the perimeter growth rate was lower, pain scores (VAS) were reduced, and ROM values were improved in CTC and NT groups compared with FC group at T4, T5, and T6 postoperatively (p < 0.01 and 0.05). Improved therapeutic outcome was observed in the CTC group, indicating patients should routinely undergo TKA with cementation through closure tourniquet application.

Effects of tourniquet application on enhanced recovery after surgery (ERAS) and ischemia-reperfusion post-total knee arthroplasty: Full- versus second half-course application.

PURPOSE: Pneumatic tourniquets are used in total knee arthroplasty (TKA) for surgical field visualization and improved cementation; however, their use is controversial. This study aimed to assess the effects of tourniquet application on enhanced recovery post-TKA. METHODS: A prospective randomized single-blinded trial assessed tourniquet's effects on postoperative pain, swelling, and early outcome in TKA. One-hundred and two patients with knee osteoarthritis were randomized to full-course (FC) and second half-course (SHC) application (n = 51/group). Tumor necrosis factor-alpha (TNF-α), C-C motif chemokine ligand 2(CCL-2), pentraxin-3 (PTX-3), prostaglandin E-2 (PGE-2), superoxide dismutase-1 (SOD-1), and myoglobin (Mb) were assessed by enzyme-linked immunosorbent assay, while the visual analog scale (VAS), range of motion (ROM), and thigh circumference growth rate were recorded. RESULTS: Average tourniquet duration significantly differed between the SHC (37.5 ± 5.1 min) and FC (66.4 ± 7.2 min) groups (p < 0.01); VAS and thigh circumference growth rate in the SHC group were much lower compared with the FC group, while ROM was higher within 48 h of tourniquet removal (p < 0.01). Blood TNF-α, PTX3, CCL2, PGE2, SOD-1, and Mb were lower in the SHC group than the FC group (p < 0.01). Additionally, intraoperative blood loss was significantly elevated in the SHC group than the FC group (p < 0.01), with lower postoperative blood loss in the drain (p = 0.001). Postoperative drainage volume was reduced in the SHC group compared with the FC group (p < 0.01); five and two patients in the FC and SHC groups required blood transfusion, respectively (p = 0.025). Hospital stay tended to be shorter in the SHC group (p = 0.023), and no tourniquet-related complications were recorded. CONCLUSION: Improved therapeutic outcome was observed in the SHC group, indicating patients should routinely undergo TKA with SHC tourniquet application.

Improvement of calcium phosphate scaffold osteogenesis in vitro via combination of glutamate-modified BMP-2 peptides.

Alpha-tricalcium phosphate (α-TCP) based porous scaffolds have superior osteoconduction and osteoinduction in bone tissue engineering, furthermore, these 3D porous scaffolds can be used as efficient drug delivery carriers. In the concept of tissue engineering, the "drugs" could be defined as drug molecules or biomacromolecules, even cells. These "drugs" have endowed the scaffolds which were laden improved abilities compared with the blank scaffolds. In this study, we anchored osteogenic bone morphogenetic protein-2 (BMP-2) derived peptides to α-TCP 3D porous scaffolds by linking the E7 domain to the target peptides, constructed the modified active peptides (E7BMP-2 peptides) delivery system, which finally achieved the modified peptides sustaining release and enhanced rat bone marrow mesenchymal stem cells (BMSCs) osteogenic differentiation in vitro. The α-TCP 3D porous scaffolds had micropores and interconnected micropores which expanded surface area of the scaffolds. The release test testified the constructed the delivery system had realized long-term release in which the peptides dosage could be detected by the BCA protein assay kit after 10 days compared with BMP-2 proteins which absorbed on the same α-TCP 3D porous scaffolds. The constructed E7BMP-2 peptides delivery system supported rat BMSCs osteogenic differentiation in the form of improving the genes expression levels of Runx2, ALP and OCN. Based on electrostatic interactions, E7 domain fastened combination between the active BMP-2 derived peptides and the α-TCP 3D porous scaffolds, the sustaining E7BMP-2 peptides release promoted the BMSCs osteogenesis as BMP-2 proteins did, which endowed α-TCP 3D porous scaffolds enhanced osteoinductive abilities in vitro.