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.
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.
This study is aimed to investigate the effects of mechanical stretch on the expression of transforming growth factor-β1 (TGF-β1) and fibroblast growth factor-2 (FGF-2), and the signaling pathway in human bronchial epithelioid (16HBE) cells under mechanical stretch. Using loading device with flexible substrate (FX-4000T) to stretch 16HBE cells, we found that the stretching elongation was 15%, at frequency of 1 Hz, stretching for 0.5 h, 1 h, 1.5 h and 2 h. Choosing the higher expression of TGF-β1, FGF-2 and Ca2+ group to carry out intervention experiments, we used the cells pretreated with canonical transient receptor potential 1 (TRPC1) channel antagonist SKF96365, protein kinase C (PKC) inhibitor HA-100, and thereafter mechanical stretch to interpose. Compared with those in the blank control group, TGF-β1 and FGF-2' protein and mRNA, intracellular Ca2+ fluorescence intensity were higher, and the differences were statistically significant (P < 0.05) at the 4 time points, 0.5 h, 1 h, 1.5 h and 2 h. At 0.5 h, the increasing rate was the highest. TGF-β1 protein and mRNA, FGF-2 protein and mRNA, intracellular Ca2+ luorescence intensity in the stretch+SKF96365 and stretch+HA-100 intervented group were decreased, the differences were statistically significant than those in 0.5 h stretch group (P < 0.05) without intervention. The expression of TGF-β1, FGF-2 was up-regulated in 16HBE cells under mechanical stretch, PKC, TRPC1, and Ca2+ may participate in the signal path.
Objective To observe the effects of mechanical stretch on cytokines release from alveolar macrophages( AMs) and the expression of macrophage inflammatory protein-2( MIP-2) induced by lipopolysaccharide( LPS) . Methods AMs were divided into the following groups: ①AMs were subjected to 20% elongation by Flexercell 4000T cell stress system for 24 hours and the supernatant was collected to detect the levels of TNF-α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12, IFN-γ, macrophage inflammatory protein-1α( MIP-1α) , MIP-2, monocyte chemoattractant protein-1( MCP-1) , granulocyte /macrophage colony stimulating factors( GM-CSF) , interferon inducible protein-10( IP-10) , regulated on activation in normal T-cell expressed and secreted( Rantes) and keratinocyte chemoattractant( KC) , by using LiquiChip system. ② AMs were subjected to 5% , 10% , 15% and 20% elongation for 24 hours and the supernatant was collected to detect the levels of MIP-2. ③AMs were subjected to 20% elongation and MIP-2 in supernatant was detected 1, 3,6, 12, and 24 hours later. ④ AMs were subjected to 20% elongation and/ or LPS at a concentration of 10 ng/mL, and MIP-2 in supernatant was detected 24 hours later. Unstretched AMs were used as control in all kind of test. Results ①The levels of IL-1β, IL-6,MIP-2, MCP-1, IFN-γand IP-10 secreted by stretched AMs were 8. 7, 4. 3, 38. 6, 4. 8, 14. 2 and 5. 0 times those of the control group( all P lt; 0. 001) . ② The levels of MIP-2 secreted by AMs subjected to 10% , 15% and 20% elongation were ( 480. 5 ±93. 1) pg /mL,( 806. 3 ±225. 9) pg/mL and ( 1335. 7 ±18. 5) pg/mL respectively, all significantly higher than those oft he control group [ ( 34. 6 ±11. 4) pg/mL, all P lt;0. 001] . ③ Three hours after the stimulation of stretch the level of MIP-2 began to increase gradually. And 6, 12, and 24 hours after the stimulation the levels of MIP-2 secreted by the AMs were ( 819. 4 ±147. 5) pg/mL, ( 1287. 6 ±380 ±3 ) pg/mL and ( 1455. 9 ±436. 7) pg/mLrespectively, all significantly higher than those of the control group[ ( 33. 4 ±10. 2) pg/mL, all P lt; 0. 001] . ④When the AMs were stimulated individually by LPS( 10 ng /mL) or mechanical stretch ( 20% ) , the levels of MIP-2 increased to ( 1026. 3 ±339. 5 ) pg/mL and ( 1335. 7 ±318. 5 ) pg/mL respectively( both P lt; 0. 001) . When the AMs were costimulated by LPS and mechanical stretch, the level of MIP-2 increased to ( 2275. 3 ±492. 1) pg/mL, implicating a synergistic effect between mechanical stretch and LPS ( F = 121. 983, P lt; 0. 001) . Conclusions Mechanical stretch activates AMs to produce multiple inflammatory cytokines and induce AMs to secret MIP-2 in a strength- and time-dependent manner.Mechanical stretch also has synergistic effect with LPS in inducing MIP-2 release, which might play an important role in the development of ventilator-induced lung injury.
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.
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 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 isolate the tendon stem cells (TSCs) from rat patellar tendon and to investigate the effect of mechanical stretching on the expression of Sox-9. MethodsTSCs were isolated from Sprague Dawley rat (12 weeks old) patellar tendon by collagenase digestion and low density culture. The cell colony morphology and number were observed by crystal violet staining;the cell morphology was observed by inverted phase contrast microscope, and the immunophenotypes of mesenchymal stem cells (MSCs) were determined by flow cytometry. The TSCs at passage 3 was given the mechanical stretching at 4%, 0.17 Hz for 4 hours and 24 hours in the experimental group, and cells without stretching was used as control. The Sox-9 gene and protein expressions were detected by real-time fluorescence quantitative PCR and Western blot. ResultsPrimary cells showed clonal growth and star shape;after subculture, cells at passage 1 showed fibroblast-like shape. The cells formed cell colonies after 7 days;the expressions were positive for CD29, CD44, and CD90 and negative for CD45. The result of real-time fluorescence quantitative PCR showed that Sox-9 gene was down-regulated at 4 hours after mechanical stretching compared with control (P<0.05), and up-regulated at 24 hours after mechanical stretching when compared with control group (P<0.05). The result of Western blot showed that Sox-9 protein expression was lower at 4 hours after stretching, but higher at 24 hours after mechanical stretching than that in control group (P<0.05). ConclusionThe rat patellar TSCs can be isolated successfully, and mechanical stretching inhibits the Sox-9 expression, but the inhibited effect might stimulate the Sox-9 expression after the mechanical stretching effect disappears.
Objective To investigate the guiding value of bedside lung ultrasound and lung stretch index for optimal positive end-expiratory pressure (PEEP) in lung recruitment of patients with acute respiratory distress syndrome (ARDS). Methods From February 2020 to October 2023, 90 patients with ARDS requiring invasive mechanical ventilation were selected from the Department of Critical Care Medicine, the Second Affiliated Hospital of Zhengzhou University. According to the setting method of PEEP after lung recruitment, they were randomly divided into an ultrasound group (45 cases) and a stretch group (45 cases). Both groups were treated with PEEP incremental method for lung recruitment, and the ultrasound group was treated with bedside ultrasound-guided method to set PEEP after lung recruitment. PEEP was set by lung stretch index method in the stretch group. The dynamic changes of oxygenation index (PaO2/FiO2), dynamic compliance (Cdyn), mean airway pressure and peak airway pressure were monitored before lung recruitment and 15 min, 1 h, 6 h and 24 h after lung recruitment. Heart rate, mean arterial pressure and central venous pressure were monitored before and 24 h after lung recruitment in the two groups. The optimal PEEP value and the corresponding volume at the end of recruitment were explored. The mechanical ventilation time, ICU hospitalization time, incidence of barotrauma, incidence of extrapulmonary organ failure, and 28-day mortality were recorded as well. Results After lung recruitment, the oxygenation index, Cdyn, mean airway pressure, and peak airway pressure in the ultrasound group were higher than those in the stretch group at 15 min, 1 h, 6 h, and 24 h after recruitment (all P<0.05). There was no significant difference in heart rate, mean arterial pressure or central venous pressure between the two groups at 24 h after lung recruitment (all P>0.05). After lung recruitment, the optimal PEEP value and the corresponding volume at the end of recruitment in the ultrasound group were higher than those in the distraction group (both P<0.05). The mechanical ventilation time and ICU stay in the ultrasound group were shorter than those in the stretch group (both P<0.05). There was no significant difference in the incidence of barotrauma, extrapulmonary organ failure rate or 28-day mortality between the two groups (all P>0.05). Conclusions Both bedside lung ultrasound-guided PEEP and lung stretch index-guided PEEP can improve oxygenation and respiratory compliance, and have no adverse effects on hemodynamics. Bedside lung ultrasound-guided PEEP can make the alveoli fully expand, which is more conducive to improving patients’ oxygenation and respiratory compliance, and the guiding value is higher than the lung stretch index.
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.