Fibrosis in frozen shoulder: Activation of IL-6 through PI3K-Akt signaling pathway in synovial fibroblast.

Fibrosis is the main cause of limited range of motion (ROM) of shoulder in patients with frozen shoulder (FS). Overexpression of Interleukin 6 (IL-6) has been correlated with pathogenesis of FS. However, the underlying mechanism remains largely unexplored. In the current study, we focused on isolating synovial fibroblasts of FS and determining the influence of IL-6 as well as PI3K-Akt signaling pathway on the fibrotic process of synovial fibroblasts in FS by using RNA Sequencing (RNA-seq) and other molecular biology techniques. Synovial fibroblasts of FS express more extra cellular matrix (ECM) than that of control. RNA-seq results and bioinformatic analysis indicate that PI3K-Akt signaling pathway play an important role in the fibrotic process of FS, and IL-6 is the most related gene among those related to this process. The expression levels of IL-6 / IL-6R in FS synovial fibroblasts and IL-6 in culture supernatant were both significantly increased. siRNA interference with the expression of IL-6 attenuates the fibrosis level of FS as well as phosphorylation level of Akt. The findings suggest that synovial fibroblasts are key effector cells of fibrosis of FS. Activation of PI3K-Akt pathway can promote fibrosis of synovial fibroblasts in FS. IL-6 is up-regulated in synovial fibroblasts of FS and promoted the FS fibrosis through PI3K-Akt signaling pathway.

H-loop Knotless Double-Row Repair Versus Knotted Suture Bridge for Rotator Cuff Tears: A Biomechanical and Histological Study in an Animal Model [Formula: see text].

BACKGROUND: Knotted suture bridge repair (KSBR) has been widely proven to be an effective method for rotator cuff repairs. However, the occurrence of type 2 failure after suture bridge repair remains a frequent problem because of the stress concentration and disturbance of tendon perfusion in the medial row. The authors have developed the H-loop knotless double-row repair (HLDR) to counteract these problems. PURPOSE: To compare the biomechanical and histological outcomes of HLDR and KSBR for rotator cuff tear in the rabbit model. STUDY DESIGN: Controlled laboratory study. METHODS: Acute bilateral supraspinatus tears were created on the shoulders of 46 New Zealand White rabbits. HLDR and KSBR were randomly performed on the left side or right side. Thirteen animals each were sacrificed at 2, 4, and 8 weeks after surgery (n = 39), with 6 rabbits used for histological evaluation and the other 7 rabbits for biomechanical testing. The remaining 7 animals from the original 46 were only used for initial biomechanical evaluation at week 0. RESULTS: Macroscopically, all repaired tendons were connected to their footprint on the greater tuberosity without postoperative complications at 8 weeks after surgery. The HLDR group had significantly better histological bone-to-tendon integration compared with the KSBR group in terms of fibrocartilage regeneration, collagen composition, and fiber organization. The biomechanical outcomes in the HLDR group were demonstrated to be better than those of the KSBR group at time 0 and 8 weeks after surgery. CONCLUSION: Both repair techniques were effective for rotator cuff tears in a rabbit rotator cuff tear model; however, HLDR demonstrated more advantages in improving biomechanical properties and histological tendon-to-bone healing compared with KSBR. CLINICAL RELEVANCE: This animal study suggested that HLDR might be an alternative choice for rotator cuff tears in humans to increase tendon-to-bone healing and reduce the rate of failure to heal.

[Visualization research of three-dimensional microstructure of rabbit sciatic nerve bundles by micro-CT].

Objective: To realize the visualization of three-dimensional microstructure of rabbit sciatic nerve bundles by micro-CT and three-dimensional visualization software Mimics17.0. Methods: The sciatic nerve tissues from 6 New Zealand rabbits were divided into 2 groups ( n=3), and the sciatic nerve tissues were stained by 1% (group A) and 5% (group B) Lugol solution respectively. After staining for 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 hours, the imaging changes of specimens were observed by light microscope and micro-CT. The clear micro-CT images were exported to the Mimics software to complete the visualization of three-dimensional microstructure of rabbit sciatic nerve according to three-dimensional reconstruction tool. Results: The clear three-dimensional microstructure images could be observed in group A at 2.5 hours after staining and in group B at 1.5 hours after staining by light microscope and micro-CT. The sciatic nerve of New Zealand rabbits were divides into 3 bundles and each of them was relatively fixed. There was no obvious crossing or mergers between each bundle. The cross-sectional area of each bundle was (0.425±0.013), (0.038±0.007), and (0.242±0.026) mm 2 respectively. The digital model could clearly reflect the microstructure of the sciatic nerve at all cross sections. Conclusion: The internal structure of New Zealand rabbits sciatic nerve can be clearly reflected by micro-CT scanning. It provides a reliable method for establishing a nerve microstructure database with large amount specimens.