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.
OBJECTIVE: To investigate the availability and effect of skin stretch in closing the firearm injured soft tissue defect. METHODS: Eight white pigs with firearm injured soft tissue defect were divided into 3 groups. Each group I and group II had 3 pigs which were performed skin stretch. The control group had 2 pigs without stretch. The average diameter of the defect in three groups was (7.3 +/- 0.2) cm, (9.1 +/- 0.3) cm, (7.3 +/- 0.2) cm respectively, and the site of defect was on the lateral thigh and buttock. RESULTS: Skin stretch could make a visible reduction of the wound. It was possible to close the wound by direct traction when the diameter of the buttock wound was less than 7 cm, and when the diameter of the lateral thigh wound was less than the radius of thigh. The skin stretch should not last more than 7 days and the best effect appeared in 4 to 5 days after performing the skin stretch. CONCLUSION: The skin stretch can be applied in the repair of the firearm injured soft tissue defect. It has many advantage compared with the tradtional treatment.
ObjectiveTo investigate the effectiveness of channel screw combined with skin-stretching technique in treatment of pelvic fracture with severe Morel-Lavallée lesion.MethodsBetween January 2017 and May 2020, 11 patients with pelvic fractures complicated with severe Morel-Lavallée lesions were treated with channel screw combined with skin-stretching technique. There were 8 males and 3 females, with an average age of 39.2 years (range, 28-58 years). Causes of injury included traffic accident in 9 cases and falling from hight in 2 cases. The time from injury to hospital admission ranged from 1 to 6 days (mean, 3.7 days). According to the Tile classification, the pelvic fractures were rated as type C1 in 7 cases, type C2 in 3 cases, and type C3 in 1 case. The sites of Morel-Lavallée lesions were buttocks in 8 cases, hips in 2 cases, and thigh in 1 case. There was 1 case of rectal injury, 1 case of splenic rupture, 3 cases of craniocerebral injury, 2 cases of chest injury, 4 cases of spinal fracture, and 6 cases of sacral nerve injury. X-ray films were performed to observe reduction and healing of fracture. The quality of fracture reduction was evaluated by Matta standard at 1 week after operation. Wound healing and complications were observed. Majeed scoring was used to evaluate hip function and Gibbons sacral nerve injury grading was used to evaluate neurological function recovery.ResultsThe patients underwent 4-7 operations, with an average of 5.8 operations. The time of first operation (pelvic fracture fixation, debridement, and skin distractor installation) was 115-275 minutes, with an average of 186.5 minutes. The amount of intraoperative blood loss was 30-80 mL, with an average of 45.5 mL. All patients were followed up 6-12 months, with an average of 8.3 months. The quality of fracture reduction according to the Matta standard was excellent in 7 cases, good in 2 cases, and fair in 2 cases, with an excellent and good rate of 81.8%. All fractures healed at 3-6 months after operation, with an average of 4.5 months. At last follow-up, the hip functions were excellent in 7 cases and good in 4 cases according to Majeed scoring, with an excellent and good rate of 100%. Among the 6 patients complicated with sacral nerve injury, the Gibbons sacral nerve injury grading reached gradeⅠ for 4 cases, gradeⅡ for 1 case, and grade Ⅲ for 1 case. The wounds of 9 cases were sutured directly after skin-stretching treatment for 25-32 days, with an average of 28 days. The dermal edge necrosis occurred in 1 case, and the defect was repaired by free skin grafting. The skin superficial dry necrosis of the wound occurred in 1 case, and healed by dressing change.ConclusionIn the treatment of pelvic fracture complicated with severe Morel-Lavallée lesion, the channel screw and skin-stretching technique showed their own advantages, which can obtain early fracture fixation and good wound healing.
Objective To investigate the effects of different mechanical stretch conditions on the differentiation of rat tendon stem cells (TSCs), to find the best uniaxial cyclic stretching for TSCs tenogenic differentiation, osteogenic differentiation, and adipogenic differentiation. Methods TSCs were isolated from the Achilles tendons of 8-week-old male Sprague Dawley rats by enzymatic digestion method and cultured. The TSCs at passage 3 were randomly divided into 5 groups: group A (stretch strength of 4% and frequency of 1 Hz), group B (stretch strength of 4% and frequency of 2 Hz), group C (stretch strength of 8% and frequency of 1 Hz), group D (stretch strength of 8% and frequency of 2 Hz), and group E (static culture). At 12, 24, and 48 hours after mechanical stretch, the mRNA expressions of the tenogenic differentiation related genes [Scleraxis (SCX) and Tenascin C (TNC)], the osteogenic differentiation related genes [runt related transcription factor 2 (RUNX2) and distal-less homeobox 5 (DLX5)], and the adipogenic differentiation related genes [CCAAT-enhancer-binding protein-α (CEBPα) and lipoprteinlipase (LPL)] were detected by real-time fluorescent quantitative PCR and the protein expressions of TNC, CEBPα, and RUNX2 were detected by Western blot. Results The mRNA expressions of SCX and TNC in group B were significantly higher than those in groups A, C, D, and E at 24 hours after mechanical stretch (P<0.05). The mRNA expressions of CEBPα and LPL in group D were significantly higher than those in groups A, B, C, and E at 48 hours after mechanical stretch (P<0.05). The mRNA expressions of RUNX2 and DLX5 in group C were significantly higher than those in groups A, B, D, and E at 24 hours after mechanical stretch (P<0.05). Western blot detection showed that higher protein expression of TNC in group B than group E at each time point after mechanical stretch (P<0.05), and the protein expression of CEBPα was significantly inhibited when compared with group E at 24 hours after mechanical stretch (P<0.05). At 24 hours after mechanical stretch, the protein expression of RUNX2 in group C was significantly higher than that in group E (P<0.05); and the protein expression of TNC was significantly lower than that in group E at 24 and 48 hours after mechanical stretch (P<0.05). At 48 hours after mechanical stretch, the protein expression of CEBPα was significantly increased and the protein expression of TNC was significantly decreased in group D when compared with group E (P<0.05), but no significant difference was found in the protein expression of RUNX2 between groups D and E (P>0.05). Conclusion The mechanical strain could promote differentiation of TSCs, and different parameter of stretch will lead to different differentiation. The best stretch condition for tenogenic differentiation is 4% strength and 2 Hz frequency for 24 hours; the best stretch condition for osteogenic differentiation is 8% strength and 1 Hz frequency for 24 hours; and the best stretch condition for adipogenic differentiation is 8% strength and 2 Hz frequency for 48 hours.
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.
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.
ObjectiveTo summarize the effectiveness of delayed skin-stretching device in treatment of skin and soft tissue defects.MethodsBetween December 2014 and December 2016, 10 cases of skin and soft tissue defects were treated with delayed skin-stretching device. There were 6 males and 4 females with an average age of 53 years (range, 42-64 years). The skin and soft tissue defects were caused by acute trauma in 6 cases. The incision could not be closed directly after making incisions because of osseous fascia syndrome in 3 cases. The skin soft tissue defect caused after huge carbuncle incision and drainage in 1 case. The defect located at thigh in 4 cases, lower leg in 3 cases, upper arm in 2 cases, back in 1 case. The defect area ranged from 10 cm×4 cm to 22 cm×12 cm. Pinch test was performed on the wound margin, which confirmed that the wound could not be closed directly.ResultsTension blisters were found in 3 cases during traction, and no complications such as impaired blood circulation or skin necrosis occurred in all cases. Skin defects closed directly after continuously stretching for 7-18 days. No skin graft or free flap repair was performed in all patients. The wound healed well after operation. All the 10 patients were followed up 5-8 months (mean, 6.5 months). There was no necrosis around the wound margin and the scar was linear. The sensation and function were not affected.ConclusionDelayed skin-stretching device is an effective method to treat skin and soft tissue defects, which has the advantages of simple operation, lower risk of operation, less complications, and reliable effectiveness.
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.
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.