Objective To explore the effects of mechanical stretch with variant frequencies on the alignment and differentiation of the multilayer myotubes cultured in vitro, and to select the optimized cultural condition of regenerative skeletal muscle tissue with stress loading cultured in vitro. Methods C2C12 myoblasts cultured in vitro in the groove casts of Sylgard 184 were induced into the multilayer myotubes. Meanwhile the myoblasts were treated with various mechanical stretch withcells tensile instrument, at the amplitude of 10% and the frequency of 0 (group A), 0.25 (group B), 0.50 (group C), and 1.00 Hz (group D) for 1 hour, 3 times a day. The myotubes morphology was observed by inverted phase contrast microscope at 5, 7, and 10 days after continuous mechanical stretch. And the expressions of mRNA for myogenic differentiation antigen (MyoD), Myogenin, Desmin, and myosin heavy chain (MyHC) were detected by RT-PCR and real-time fluorescent quantitative PCR (QRT-PCR), respectively. Results The mechanical stretch could promote the al igned fusion and increase the number of myotubes. Indeed the multilayer myotubes arranged more closely in group B at 7 days. At the same group, as the time went on, the mRNA expressions of MyoD gradually decl ined in each group. There were significant differences in mRNA expressions of MyoD between 5 days and 7, 10 days (P lt; 0.05). The mRNA expressions of Myogenin, Desmin, and MyHC were highest at 7 days. There were significant differences between different time points (P lt; 0.05), except the mRNA expression of Desmin of group B between 7 and 10 days (P gt; 0.05). At the same time, with the increase of frequency, the highest mRNA expressions of MyoD, Myogenin, Desmin, and MyHC were in group B. There were significant differences at the same time between group B and the other groups (P lt; 0.05), except mRNA expression of Desmin at 5 days between groups B and C, and mRNA expression of MyHC at 10 days between groups A and B (P gt; 0.05). Conclusion Low frequency (0.25 Hz) and suitable time (7 days) periodic mechanical stretch is beneficial to the differentiation of the multilayer myotubes cultured in the groove casts of Sylgard 184, but as the stretch time goes on the aging of myotubes will be accelerated.
Objective To investigate the effect of stretch on long non-coding RNA taurine upregulated gene 1 (TUG1)-mediated miR-545-3p/cannbinoida receptor 2 (CNR2) pathway regulating bone regeneration in the distraction area of rats during distraction osteogenesis. MethodsThirty-six 10-week-old male Sprague Dawley rats were randomly divided into 3 groups (n=12 in each group): group A (femoral fracture+injection of interfering RNA), group B (distraction osteogenesis+injection of interfering RNA), and group C (distraction osteogenesis+injection of TUG1). Groups A and B were injected with 60 μg of interfering RNA at the beginning of incubation period (immediate after operation), the beginning of distraction phase (7 days after operation), and the end of distraction phase (21 days after operation), and group C was injected with 60 μg of synthetic TUG1 in vivo interfering sequence at the same time. The general situation of rats in each group was observed during the experiment. The mineralization of fracture space or distraction area was observed by X-ray films at 21, 35, and 49 days after operation. At 49 days after operation, the samples of the distraction area were taken for HE staining to observe the mineralization, and real-time fluorescence quantitative PCR (qRT-PCR) was used to detect the expressions of osteoblast-related genes such as TUG1, miR-545-3p, CNR2, alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). Blood samples were collected from the abdominal aorta of the rats, and the expressions of ALP and C terminal telopeptide of type Ⅰ (CTX-Ⅰ) protein were detected by ELISA assay.Results The results of X-ray film and HE staining observations showed that osteogenesis in group C was superior to groups A and B at the same time point. The results of qRT-PCR showed that the relative mRNA expressions of TUG1, CNR2, ALP, OCN, and OPN in group C were significantly higher than those in group A and group B, and the relative mRNA expression of miR-545-3p in group C was significantly lower than that in group A and group B (P<0.05). The relative mRNA expressions of TUG1 and ALP in group B were significantly higher than those in group A, and the relative mRNA expression of miR-545-3p in group B was significantly lower than that in group A (P<0.05). There was no significant difference in the relative mRNA expressions of CNR2, OCN, and OPN between group A and group B (P>0.05). The results of ELISA showed that the expressions of ALP and CTX-Ⅰ protein were significantly higher in group C than in group A and group B, and in group B than in group A (P<0.05). ConclusionUnder the action of stretch, the expression of TUG1 in the femoral distraction area of rats increases, which promotes the expression of CNR2 by inhibiting the expression of miR-545-3P, which is helpful to the mineralization of the extension area and osteogenesis.
ObjectiveTo investigate the effectiveness of distraction therapy assisted by arthroscope in the treatment of ankle traumatic osteoarthritis. MethodsBetween October 2013 and October 2014, 13 patients with ankle traumatic osteoarthritis were treated, including 8 males and 5 females with an age range of 44-63 years (mean, 55.2 years). The left ankle and the right ankle were involved in 4 and 9 cases respectively. The disease duration was 1.5-10.0 years (median, 5 years). The American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hind foot scale score was 51.00±7.09; the short-form 36 health survey scale (SF-36) score was 40.82±4.62. According to Scranton grade system, 9 cases were rated as grade II and 4 cases as grade III. First, ankle hyperplasia osteophytes was removed under arthroscope, then Ilizarov apparatus was used to maintain distraction of 5-10 mm ankle space for 3 months. ResultsOne case had postoperative pin tract infection after removing the external fixation, and infection was controlled by dressing treatment; no related complications occurred in the other patients. All patients got follow-up of 12-18 months (mean, 14.7 months). Patients achieved disappearance of ankle swelling, pain relief, and were able to walk after rehabilitation. The ankle activity was obviously improved. At last follow-up, AOFAS ankel-hind foot scale score and SF-36 score were significantly increased to 85.23±6.41 and 56.29±6.20 respectively (t=20.756, P=0.025; t=11.647, P=0.018). According to AOFAS scores, the results were excellent in 4 cases, good in 8 cases, and fair in 1 case; the excellent and good rate was 92.3%. Postoperative X-ray film showed normal ankle position and alignment, osteophytes at the edges of the tibia and talus, articular surface sclerosis, normal joint space, and no joint swelling. ConclusionDistraction therapy assisted by arthroscope is an effective method for treating ankle traumatic osteoarthritis.
Idiopathic pulmonary fibrosis (IPF) is a progressive scar-forming disease with a high mortality rate that has received widespread attention. Epithelial mesenchymal transition (EMT) is an important part of the pulmonary fibrosis process, and changes in the biomechanical properties of lung tissue have an important impact on it. In this paper, we summarize the changes in the biomechanical microenvironment of lung tissue in IPF-EMT in recent years, and provide a systematic review on the effects of alterations in the mechanical microenvironment in pulmonary fibrosis on the process of EMT, the effects of mechanical factors on the behavior of alveolar epithelial cells in EMT and the biomechanical signaling in EMT, in order to provide new references for the research on the prevention and treatment of IPF.
ObjectiveTo evaluate the clinical value of skin stretching device in repair of diabetic foot wound.MethodsA retrospective analysis was made on the clinical data of 48 cases with diabetic foot wound who were treated with skin stretching device (trial group, n=24) and with the vacuum sealing drainage combined with skin graft (control group, n=24) respectively between October 2015 and July 2016. There was no significant difference in gender, age, side, course of disease, TEXAS stage between 2 groups (P>0.05). Both patients in 2 groups were treated with sensitive antibiotics according to the results of bacterial culture.ResultsOne case in control group was infected and the skin graft failed, and 1 case in trial group was infected after the treatment, and the two wounds healed after symptomatic treatment. The wounds of the other patients healed successfully, and the healing time of the trial group was significantly shorter than that of the control group [(12.8±11.6) days vs. (22.3±10.4) days; t=2.987, P=0.005). All patients were followed up 3-12 months after operation, and no wound dehiscence or recurrence occurred during follow-up.ConclusionCompared with the vacuum sealing drainage combined with skin graft, the application of skin stretching device in the repair of diabetic foot wound has advantages, such as easy to operate, shorten the wound healing time, and the appearance of wound was similar with the adjacent skin.
Objective To investigate the application of modified adjustable skin stretching and secure wound-closure system in repairing of skin and soft tissue defect. Methods Between March 2016 and April 2017, 21 cases of skin and soft tissue defects were repaired with the modified adjustable skin stretching and secure wound-closure system (the size of regulating pressure and the times of adjustment were determined according to the color, temperature, capillary response, and swelling degree of the skin edge). There were 11 males and 10 females, with an average age of 49.2 years (range, 21-67 years). Among them, 1 case was the residual wound after amputation of leg; 18 cases were the wounds after traumatic injury operation, including 4 cases in the lower leg, 3 cases in the knee joint, 7 cases in the upper limb, and 4 cases in the foot; and 2 cases were diabetic feet. The skin defect area ranged from 4.0 cm×2.5 cm to 21.0 cm×10.0 cm. Results Skin defect wounds closed directly in one stage in 4 cases; 12 cases were closed after continuously stretching for 5-14 days (mean, 10 days); 5 cases were reduced to less than one-half area, and the wound healed after the second skin grafting or flap repairing. All the 21 patients were followed up 3-12 months (mean, 5.2 months). The wound was linear healing with small scar, and no invasive margin, poor blood flow, necrosis, and poor sensory function happened. Conclusion The modified adjustable skin stretching and secure wound-closure system can reduce the skin and soft tissue defects or close the wound directly, and even replace the skin graft and skin flap repairing. It was a good method for the treatment of skin and soft tissue defect.
This study was aimed to design a new, accurate and easy-to-use water bath cryo-jaw, and try to solve the problems met in small animals achilles tendon mechanical testing. The muscle-tendon-bony units were fixed in the clamps. SD rats achilles tendon were randomly divided into group A and B. Group A was tested by the newly designed water bath cryo-jaw, while group B was treated by non-water bath cryo-jaw. The mechanical tests revealed that non of the samples of the newly-designed water bath cryo-jaw in group A slipped and fell off, and the achilles tendons were in a physiologically active state, but one of the group B samples slipped and fell off, and the others had the frozen phenomenon obviously. The maximum stress, fracture displacement and Young's modulus of the rats in group A were significantly different compared to those in group B (P<0.05). In conclusion, the new water bath cryo-jaw has more advantages than traditional ones. It exhibits a good simulation in vivo in the environmental conditions for testing the mechanical properties of the achilles tendon.
ObjectiveTo explore the reaction of normal skin fibroblasts from different sites of human body to cyclic stretch. MethodsThe normal skin tissues from scapular upper back and medial side of upper arm of 3 patients were cultured in vitro. Fibroblasts of experimental group were loaded by cyclic stretch with 10% amplitude for 24, 36, and 48 hours respectively. Fibroblasts of control group were cultured without cyclic stretch. The morphologic changes were observed using inverted microscope. CCK-8 method was used to detect the proliferation of the fibroblasts. The expressions of integrin β1 mRNA, p130Crk-associated substance (P130Cas) mRNA, transform growth factor β1 (TGF-β1) mRNA, and collagen type Ⅰ α1 chain (COL1A1) mRNA were detected by real-time quantitative PCR. The protein levels of collagen type Ⅰ and TGF-β1 were detected by ELISA. ResultsThe cultured cells showed a significantly increased cell proliferation ability, and apparent orientation after the applied strain. The proliferation activity, mRNA expression levels of integrin β1, P130Cas, and TGF-β1, protein levels of TGF-β1 in back skin were significantly higher than those in arm skin (P<0.05) when the fibroblasts were loaded for 36 and 48 hours, but no significant difference between back skin and arm skin at 24 hours (P>0.05). There was no significant difference in mRNA expression level of COL1A1 and protein level of collagen type Ⅰ between back skin and arm skin at 24, 36, and 48 hours (P>0.05). There was no significant difference in all above indexes between back skin and arm skin in control group (P>0.05). ConclusionFibroblasts from scapular upper back and medial side of upper arm display different reactions to cyclic stretch, which indicates that there exists site difference in the reactions of fibroblasts to cyclic stretch. It might be related with the incidence of hypertrophic scar in different sites of the body.
Objective To investigate the technique of reduction by posterior approach for severe spondylolisthesis, and to discuss the method to prevent nerve stretch injury. Methods Between July 2007 and April 2011, 17 patients with severe spondylolisthesis underwent reduction, fixation, and fusion by posterior approach. There were 2 males and 15 females with a median age of 15 years (range, 8-67 years) and a median disease duration of 18 months (range, 5 months-16 years and 4 months). The level of spondylolisthesis was at L4 in 1 case and L5 in 16 cases; the spondylolisthesis was at degree III in 12 cases and degree IV in 5 cases according to Meyerding classification. There were 16 cases of developmental spondylolisthesis (high- dysplastic and low-dysplasia spondylolisthesis in 9 and 7 cases, respectively) and 1 case of traumatic spondylolisthesis; 16 cases of developmental spondylolisthesis at L5 level included 6 cases of type 4, 9 case of type 5, and 1 case of type 6 according to Spinal Deformity Study Group (SDSG) classification. All cases underwent posterior spinal decompression, Schanz screw fixation for the slipped vertebrae, the intervertebral and posterolateral fusion and reduction of the slipped vertebrae, and correction of the lumbosacral kyphosis. The reductive degree of slipped vertebrae was modulated according to the strain of exiting spinal root. The slip degree should be reduced within Meyerding degree II. The anteroposterior and lateral radiographs of whole spine were taken in a standardized standing position to observe the correction of displacement severity and lumbosacral angle. The nerve function and pain score of lower extremity were evaluated by neurological Frankel grade and visual analogue scale (VAS). Bony fusion was assessed by followed-up CT three-dimentional reconstruction. Results Exiting nerve root paralysis occurred in 1 case after operation, and released at 4 weeks after operation; no aggravation of nerve damage was observed in the other patients. The incisions primarily healed. All the patients were followed up 12-48 months (mean, 25 months). The slip percentage, the lumbosacral angle, and VAS score of lower extremity were improved from 72% ± 10%, (18.2 ± 3.5)°, and 7.0 ± 1.5 at preoperation to 12% ± 6%, ( — 7.3 ± 2.9)°, and 1.5 ± 1.3 at 12 months after operation respectively, all showing significant differences (P lt; 0.05). Osteosynthesis was seen at the bone grafting area by CT three-dimentional reconstruction at 12 months after operation. No breakage of screw and rod or reduction loss occurred. Conclusion It can obtain satisfactory clinical result to use spinal canal decompression by posterior approach, the Schanz screw fixation of the slipped vertebrae, the intervertebral and posterolateral fusion for severe spondylolisthesis. The risk of nerve stretch injury can be prevented by choosing the lowest height of intervertebral cage, modulating the reductive degree of slipped vertebrae according to the strain of exiting spinal root, and correcting lumbosacral kyphosis.