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Hydrogels for biomedical applications were limited toward bone tissue engineering due to the poor mechanical performance. Tough hydrogels with strong and elastic features have received extensive attention, the application of which, however, was limited by their degradation. The present study introduced an approach to enhance mechanical properties of hydrogel while ensuring its degradation. Carboxyl dextran (Dex) was grafting modified by poly (e-caprolactone) (PCL), sequentially followed by being cross-linked through polyethyleneglycol 400 (PEG400) to yield a gel with covalent cross-linking units in DMSO. The gel was underwent solvent displacement in H2 O to induce hydrophobic association of PCL to form non-covalent cross-linking units. The tough Dex-g-PCL hydrogel showed maximum strain of Dex-g-PCL hydrogel was 90% ± 6%, with the corresponding stress of 2.7 ± 0.2 MPa, which was significantly enhanced when comparing to dextran hydrogel (maximum strain 65% ± 5%, with the corresponding stress of 0.225 ± 0.06 MPa). Most hydrogel degraded after 12 w in vivo with only a little residues. Adipose-derived stem cells (ASCs) proliferated well after being seeded in hydrogel to form micro-mass at 14 days post-seeding. In vitro and in vivo angiogenesis, as well as in vitro osteogenesis illustrated the potential of the Dex-g-PCL hydrogel carrying ASCs toward vascularized bone tissue engineering. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1120-1131, 2019.

To evaluate the effectiveness and safty of posterior popliteal fossa S-shaped incision with double-window approach for the treatment of posterior column of tibial plateau fractures.A retrospective analysis was made on the clinical data of 13 patients with complex tibial plateau fractures involving both posteromedial and posterolateral columns between May 2015 and July 2017. There were 9 males and 4 females, aged 33-64 years (mean, 46.5 years). The causes of injury included traffic accident in 5 cases, falling from height in 2 cases, falling from electric bicycle in 4 cases, and falling because of skiing in 2 cases. The preoperative range of motion of the affected knees was (35.1±9.2)°. The time from injury to surgery was 7-19 days (mean, 13.3 days). All patients underwent a posterior popliteal fossa S-shaped incision through the window of medial heads of gastrocnemius muscle (medial window) and the window between medial and lateral head of gastrocnemius muscle (popliteal fossa window) approaches. After a good visual control of fracture reduction, both posteromedial and posterolateral columns of tibial plateau fractures were fixed with buttress plate respectively. Bone union, limb alignment, articular surface, and range of motion were estimated after operation. The American Hospital for Special Surgery (HSS) score was used to evaluate functional outcomes of knees.After operation, 1 patient had fat liquefaction and dehiscence of incision, which healed after expanding the wound; the other patients' incisions healed by first intention, and no vascular or nerve injury occurred during operation. All the 13 patients were followed up 12-18 months (mean, 16 months). The X-ray films showed that all patients obtained good fracture unions, the fracture healing time was 14-22 weeks (mean, 18 weeks). At 12 months after operation, the articular surface was smooth without collapse, and the knee range of motion was (109.5±13.6)°, showing significant difference when compared with preoperative value (The posterior column fracture of tibial plateau involving both posteromedial and posterolateral columns treated by double-window approach through posterior popliteal fossa S-shaped incision is safe and effective, with satisfactory results and good recovery of knee joint function.探讨后侧腘窝 S 形切口双窗口入路治疗胫骨平台后柱骨折的临床疗效和安全性。.2015 年 5 月—2017 年 7 月收治 13 例同时累及后内侧柱和后外侧柱的复杂胫骨平台骨折。其中男 9 例，女 4 例；年龄 33～64 岁，平均 46.5 岁。致伤原因：交通事故伤 5 例，高处坠落伤 2 例，骑电动车摔伤 4 例，滑雪摔伤 2 例。术前膝关节活动度（35.1±9.2）°。受伤至手术时间 7～19 d，平均 13.3 d。采用后侧腘窝 S 形切口，分别经腓肠肌内侧头内侧（内侧窗）及腓肠肌内外侧头之间（腘窝窗）进入，直视下复位骨折并接骨板内固定。术后随访观察骨折愈合、下肢力线、关节面复位情况及膝关节活动度；术后 12 个月采用美国特种外科医院（HSS）膝关节功能评定标准评价膝关节功能。.术后 1 例患者出现切口脂肪液化开裂，给予扩创后愈合；其余患者切口均Ⅰ期愈合，术中未发生血管神经损伤。患者均获随访，随访时间 12～18 个月，平均 16 个月。X 线片复查示，骨折均愈合，愈合时间 14～22 周，平均 18 周。术后 12 个月随访关节面平整，无塌陷；膝关节活动度（109.5±13.6）°，与术前比较差异有统计学意义（采用后侧腘窝 S 形切口双窗口入路治疗同时累及后内侧柱及后外侧柱的胫骨平台后柱骨折安全有效，膝关节功能恢复满意，临床疗效好。.

Autophagy is an essential cellular homeostasis mechanism that was found to be compromised in aging and osteoarthritis (OA) cartilage. Previous studies showed that resveratrol can effectively regulate autophagy in other cells. The purpose of this study was to determine whether the chondroprotective effect of resveratrol was related to chondrocyte autophagy and to elucidate underlying mechanisms. OA model was induced by destabilization of the medial meniscus (DMM) in 10-week-old male mice. OA mice were treated with resveratrol with/without 3-MA for 8 weeks beginning 4 weeks after surgery. The local intra-articular injection of resveratrol delayed articular cartilage degradation in DMM-induced OA by OARSI scoring systems and Safranin O-fast green. Resveratrol treatment increased Unc-51-like kinase1, Beclin1, microtubule-associated protein light chain 3, hypoxia inducible factor-1α, phosphorylated AMPK, collagen-2A1, Aggrecan expressions, but decreased hypoxia inducible factor-2α, phosphorylated mTOR, matrix metalloproteinases13 and a disintegrin and metalloproteinase with thrombospondin motifs 5 expressions. The effects of resveratrol were obviously blunted by 3-MA except HIF and AMPK. These findings indicate that resveratrol intra-articular injection delayed articular cartilage degeneration and promoted chondrocyte autophagy in an experimental model of surgical DMM-induced OA, in part via balancing HIF-1α and HIF-2α expressions and thereby regulating AMPK/mTOR signaling pathway.

We investigated the feasibility of the intra-articular injection of resveratrol for preventing the progression of existing cartilage degeneration in a mouse model of osteoarthritis (OA). The effects of resveratrol on the expression of silent information regulator 2 type 1 (SIRT1), hypoxia-inducible factor-2α (HIF-2α) and catabolic factors in OA cartilage was explored. OA was induced in the mouse knee via destabilization of the medial meniscus (DMM). Resveratrol was injected weekly into the operated knee beginning 4 weeks after surgery. The OA phenotype was evaluated via histological and immunohistochemical analyses at 8 weeks after DMM. Western blot analysis was performed to identify whether resveratrol modulated the interleukin (IL)-1β-induced expression of HIF-2α in human chondrocytes. Histologically, resveratrol treatment preserved the structural homeostasis of the articular cartilage and the subchondral bone. Following resveratrol injection, the expression of collagen type II was retained, but the expression of inducible nitric oxide synthase and matrix metalloproteinase-13 was reduced in OA cartilage. Moreover, the administration of resveratrol significantly induced the activation of SIRT1 and the inhibition of HIF-2α expression in mouse OA cartilage and in IL-1β-treated human chondrocytes. These findings indicate that the intra-articular injection of resveratrol significantly prevents the destruction of OA cartilage by activating SIRT1 and thereby suppressing the expression of HIF-2α and catabolic factors.

A recombinant baculovirus, rv-egfp-NK, containing a reporter gene encoding the enhanced green fluorescent protein (EGFP), was used to express nattokinase (NK), a fibrinolytic enzyme, in Spodoptera frugiperda (SF-9) cells. The recombinant protein also included a histidine tag for purification using Ni(2+) resins. The recombinant NK, approximately 30 kDa, retained fibrinolytic activity (60 U/ml). The integration of the EGFP expression cassette in the Bac-to-Bac system is thus an effective method for the expression and purification of recombinant NK protein in Spodoptera frugiperda insect cells.