Objective: This study aims to investigate the effects of sudden load changes (expected and unexpected imbalance) on the activity of muscles of the lumbar spine and their central motor control strategy in military personnel with or without chronic low back pain (LBP). Design: Bilateral sudden imbalance was examined (2 × 2 factorial design). Setting: The 117th PLA Hospital, Hangzhou, China Participants: Twenty-one male subjects with lower back pain and 21 male healthy control subjects were active members of the Nanjing Military Region land forces. Outcome measures: Independent variables: LBP vs. healthy controls and imbalance anticipation (expected and unexpected imbalance). Dependent variables: rapid reaction time (RRT) and intensity of rapid reaction (IRR) of bilateral lumbar (L3-L4) erector spinae (ES), lumbar (L5-S1) multifidus (MF), and abdominal external oblique muscles. Results: Under expected or unexpected sudden imbalance conditions, subjects with LBP demonstrated significantly greater IRR than healthy controls in ipsilateral and contralateral ES and MF, respectively (P < 0.05 for all). IRR of contralateral ES was significantly larger than that of the ipsilateral ES. A significant group effect of RRT of both ipsilateral and contralateral ES muscles and a significant time expectation effect on RRT of contralateral MF muscles were also observed. RRT of the contralateral ES muscles was significantly lower than that of the ipsilateral ES muscles (P < 0.001). Conclusions: Sudden imbalance prolonged RRT of selected trunk muscles in patients with chronic LBP. The activation amplitude increased. The results may provide a theoretical basis for a study on the pathogenesis of chronic LBP.
This study investigated spatial distribution and asymmetry of surface electromyography on lumbar muscles during a sustained contraction in soldiers with and without chronic low back pain. Twenty healthy soldiers and twenty chronic low back pain (CLBP) soldiers had performed the Sorensen test with a duration of 60 seconds. The corresponding muscle fatigue, spatial distribution, and the asymmetry of muscle activity over bilateral paraspinal lumbar regions were measured by the high-density surface electromyography (HDsEMG). The paired and independent samples t-tests were performed to compare the degree of muscle fatigue and asymmetry. The repeated-measures analyses of variance (ANOVA) were used to compare spatial distribution between groups and muscle fatigue. The baseline characteristics of soldiers between groups were comparable. CLBP soldiers had significantly less muscle fatigue on both sides of erector spinae compared to healthy ones. The spatial distribution was significantly associated with the group factor but independent of muscle fatigue. In addition, the asymmetry of erector spinae activity in the CLBP soldiers was significantly higher than the healthy one. In conclusion, uneven spatial distribution and asymmetry of lumbar muscle activity play significant roles in CLBP patients. The HDsEMG could be used as an objective method in distinguishing the function of the erector spinae between healthy individuals and CLBP patients during 1 min sustained contraction.
This study analyze the effect of exosome secreted from MSCs on osteogenic differentiation in OP rats. The exosome was obtained from cultivated MSCs isolated from OP rats with ultracentrifugation. OP rats were treated with exosome secreted from MSCs of normal rats, exosome secreted from
MSCs of OP rats and exosome secreted from MSCs of OP rats with overexpression of ALP followed by analysis of the osteogenic differentiation, the expression of ALP, Bglap and Runx2 and the targeted correlation between miR-351 and ALP. The MSCs in normal rats and OP rats were able to adhere
to wall. There was elongated. The level of miR-351 in OP rats was significantly higher than normal rats. The Runx2 expression and ALP activity in rats treated with exosome secreted from MSCs of OP rats was declined significantly compared to that from MSCs of normal rats. ALP was a target gene
of miR-351. In conclusion, the exosome secreted from MSCs of OP rats inhibits the osteogenic differentiation possibly through restraining miR-351-ALP.
This study analyzed the action of Bone marrow mesenchymal stem cells (BMSCs) transplantation on arthritis rat model. Arthritis rat model was established using bovine type II collagen and CFA. BMSCs phenotype was assessed by flow cytometry and pathological changes was analyzed by H&E
staining along with analysis of joint severity by AI score, inflammation by ELISA as well as level of NPY, MMP-2, and MMP-9. The form of passaged BMSCs was spindle shaped with positive expression of CD29 and CD44. The structure of articular cavity in arthritis rats was disordered with infiltration
of inflammatory cells which were ameliorated by BMSCs transplantation. In addition, BMSCs treatment also significantly reduced AI value, the level of VEGF, IL-17 and TNF-α as well as decreased RANK/RANKL expression and increased OPG level. In conclusion, BMSCs transplantation
ameliorates inflammation and severity in arthritis rats possibly through regulation of RANK/OPG, indicating that it might be used for the treatment of arthritis patients.
We aimed to explore the mechanism underlying microRNA-23-5p from exosomes (exo-miR-23-5p) of BMSCs in rheumatoid arthritis (RA). The candidate related genes of miR-23-5p were screened in RA by bioinformatics analysis through gain- and loss-function method along with analysis of histopathological
changes in mice and RAC2 expression as well as the level of pro-inflammatory factors. In vivo RA model was established to detect miR-23-5p’s effect on RA. miR-23-5p level was significantly reduced in RA cells and RAC2 was highly expressed. Expression of RAC2 was inhibited and
targeted by miR-23-5p in RA. Exo-miR-23-5p treatment effectively alleviated joint destruction, reduced inflammatory factor secretion in tissues and serum, as well as decreased RAC2 expression in RA model. In conclusion, the miR-23-5p in the BMSC-exo delays the inflammatory response in RA,
indicating that it might be a new target for treating RA.
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