Irreversible Electroporation Improves Tendon Healing in a Rat Model of Collagenase-Induced Achilles Tendinopathy.

BACKGROUND: Treatment of painful chronic tendinopathy is challenging, and there is an urgent need to develop new regenerative methods. Irreversible electroporation (IRE) can lead to localized cell ablation by electrical pulses and induce new cell and tissue growth. Previously, the authors' group reported that electroporation-ablated tendons fully regenerated. PURPOSE: To assess the efficiency of IRE in improving tendon healing using a collagenase-induced Achilles tendinopathy rat model. STUDY DESIGN: Controlled laboratory study. METHODS: After screening for the IRE ablation parameters, a collagenase-induced Achilles tendinopathy rat model was used to assess the efficacy of IRE in improving tendon healing via biomechanical, behavioral, histological, and immunofluorescence assessments. RESULTS: The experiments showed that the parameter of 875 V/cm 180 pulses could ablate most tenocytes, and apoptosis was the main type of death in vitro. In vivo, IRE promoted the healing process of chronic tendinopathy in the Achilles tendon of rats, based on biomechanical, behavioral, and histological assessments. Finally, immunofluorescence results revealed that IRE improved blood supply in the early stages of tendon repair and could potentially reduce neuropathic pain. CONCLUSION: IRE enhanced tendon tissue healing in a rat model of collagenase-induced Achilles tendinopathy. CLINICAL RELEVANCE: IRE may as a potential alternative treatment for tendinopathy in clinical usage.

[An experimental study on percutaneous autologous bone marrow mesenchymal stem cell grafting for bone defect].

OBJECTIVES: To investigate in vive osteogenic potential in size-critical bone defect after percutaneous autologous grafting of culture-expanded rabbit autologous BMSCs, osteo-induced BMSCs and combination of both. METHODS: BMSCs were cultured and then induced with osteogenic supplement (OS) medium. BMSCs with and without OS induction were collected and percutaneously autologously injected respectively into the 15 mm bone defect of 20 experimental rabbit model. The grafts were BMSCs, osteo-induced BMSCs, BMSCs and osteo-induced BMSCs, BMP combined with fibrin sealant, and 0.9% NaCl solution. Osteogenesis at the defect areas were observed by regular radiography, histology and biomechanics. RESULTS: The group transplanted with BMSCs + osteo-induced BMSCs achieved complete bone healing with medullary cavity united, which showed the largest quantity of new bone measured by X-ray analysis, and also their maximal load were better than those in other groups. CONCLUSION: The bone-forming ability of rabbit osteo-induced BMSCs combined with BMSCs in bone defect is superior to those of BMSCs and osteo-induced BMSCs.

[Relationship between the operation time of multiple fractures with system inflammation changes and clinical outcomes].

OBJECTIVE: To investigate the relationship between the operation time of femur shaft fracture with post-operation system inflammation changes and clinical outcomes for those multiple fractures. METHODS: This investigation was designed as a prospective, nonrandomized cohort study. From April 2005 to August 2007, all 78 hospitalized patients were divided into 3 groups by an inclusion criteria: multiple fractures with opened fracture of femur shaft (group A, n = 26), multiple fractures with closed fracture of femur shaft (group B, n = 23), single closed fracture of femur shaft (group C, n = 29). In the group A, damage control orthopaedics (DCO) procedure were performed. In the group B and C, all the femur shaft fractures were performed intramedullary nail fixation early (< 24 h). From serially sampled venous blood, inflammatory reaction index were estimated by measured the concentration of IL-6, TNF-alpha surround the operation, and the conditions of multiple organs were estimated by assayed PaO2/FiO2, total bilirubin (TBIL), creatinine (Cr) levels, the postoperation complication rates were analyzed among each groups. The extent of inflammation changes, multiple organs damage conditions and postoperation complication rates were compared and analyzed among the 3 groups. RESULTS: In the group A, the median increase values of IL-6,TNF-alpha after the secondary surgery were 59 ng/L and 85 ng/L, whereas they were 154 ng/L and 250 ng/L respectively in the group B, there was a significant difference between the 2 groups (P < 0.01). In addition, the median increase values of IL-6, TNF-alpha after the first surgery in group A and in group C were both significantly less than group B (P < 0.01). Correspondingly, the abnormal rates of PaO2/ FiO2, TBIL, Cr levels occurred in the group B were all greater than group A after the 2 surgery procedures (P < 0.05), and in the aspects of average ventilation days, ICU staying days, duration of positive fluid balance (input/output > 500 ml/24 h), the group B were all greater than group A after the second surgery ( P < 0.01). Compared with group A after the first surgery, group B showed a longer average ventilation days, but it had no significant difference in average ICU stay days and duration of positive fluid balance. In addition, for group C, all the aspects above were less than group B (P < 0.01). Concerned with the complications after surgery in each groups, fat embolism and MODS rate between group A and B had no significant difference (11.5% vs 13.0% ,P > 0.05), but higher than which of group C (P < 0.01). CONCLUSIONS: The early intramedullary nail fixation of femur shaft fracture in multiple fractures may lead to a significant system inflammation changes, and may develop the subclinical changes of multiple organs. However, these changes are less in those surgery procedures later performed, namely intramedullary nail fixation of femur shaft fracture in multiple fractures as a primary definitive treatment has a potential risk, and should be carefully evaluated.