An acidic environment is vital for the maintenance of cellular activities but can be affected tremendously during intervertebral disc degeneration (IVDD). The effect of changes in the acidity of the environment on human nucleus pulposus mesenchymal stem cells (NP-MSCs) is, however, unknown. Thus, this study aimed to observe the biological effects of acidic conditions mimicking a degenerated intervertebral disc on NP-MSCs in vitro. NP-MSCs were isolated from patients with lumbar disc herniation and were further identified by their immunophenotypes and multilineage differentiation. Then, cells were cultured at acidic pH levels (pH 6.2, pH 6.5, pH 6.8, pH 7.1, and pH 7.4) with/without amiloride, an acid-sensing ion channel (ASIC) blocker. The proliferation and apoptosis of NP-MSCs and the expression of stem cell-related genes (Oct4, Nanog, Jagged, Notch1), ASICs, and functional genes (Aggrecan, SOX-9, Collagen-I, and Collagen-II) in NP-MSCs were evaluated. Our work showed that cells obtained from human degenerated NP met the criteria of International Society for Cellular Therapy. Therefore, cells obtained from a degenerated nucleus pulposus were definitively identified as NP-MSCs. Our results also indicated that acidic conditions could significantly inhibit cell proliferation and increase cell apoptosis. Gene expression results demonstrated that acidic conditions could decrease the expression of stem cell-related genes and inhibit extracellular matrix synthesis, whereas it could increase the expression of ASICs. Our study further verified that the above-mentioned biological activities of NP-MSCs could be significantly improved by amiloride. Therefore, the results of the study indicated that the biological behavior of NP-MSCs could be inhibited by acidic conditions during IVDD, and amiloride may meliorate IVDD by improving the activities of NP-MSCs.
BackgroundIntervertebral disk degeneration (IDD) is a serious public health problem associated with genetic and environmental factors. However, the pathogenic factors involved and the pathological mechanism of this disease still remain enigmatic.MethodsThe associated microarray was downloaded and further analyzed using statistical software R. The competing endogenous RNA (ceRNA) co-expression network was constructed to measure the meaningful correlated expression of differentially expressed genes. We further measured the expression of circARL15/miR-431-5p/DISC1 in IDD tissues. Cell proliferation and apoptosis were detected in NP cells transfected with a circARL15 overexpression plasmid and miR-431-5p mimics. The expression of DISC1 was detected by immunohistochemistry and Western blot analysis.ResultsWithin the ceRNA network, circARL15 is the most differentially expressed circular RNA. circARL15 was down-regulated in IDD and was negatively correlated with miR-431-5p and positively associated with DISC1. miR-431-5p was found to bind directly to circARL15 and DISC1. circARL15 inhibited nucleus pulposus cell apoptosis but promoted nucleus pulposus cell proliferation by targeting the miR-431-5p/DISC1 signaling pathway.ConclusioncircARL15/miR-431-5p/DISC1 is involved in the pathogenesis of IDD, which might be helpful in determining the diagnostic biomarkers and providing potential therapeutic targets for patients with IDD.
The study aimed to investigate the effects of postoperative position of knee on blood loss and functional recovery after total knee arthroplasty (TKA). We enrolled patients who underwent TKA from 2017 to 2019 in our department with osteoarthritis of the knee in this prospective and randomized study. The patients were randomly allocated to flexion or extension group. In the flexion group, the affected leg was elevated by 30 degrees at the hip and the knee was flexed by 30-degree, postoperatively, while in the extension group, the affected knee was fully extended postoperatively. Patients' data related to postoperative blood loss, Hospital for Special Surgery scores, pain intensity, usage of analgesic drugs, circumference of knee, and range of motion (ROM) of knee were recorded to assess the influence of postoperative leg position on clinical outcomes. Although the transfusion rate was similar between the two groups (p > 0.05), other parameters related to blood loss (including total blood loss, hidden blood loss, usage of analgesic drugs, and postoperative circumference of knee) were significantly lower in the flexion group than those in the extension group (p < 0.05). After 6 weeks and 6 months of rehabilitation, patients gained a similar ROM in the affected knee in both groups (p > 0.05). The length of hospital stay and medical expenses were similar in both groups. Incidence of wound infection and other complications was also similar in both groups (p > 0.05). Elevation of the hip by knee flexion of 30 degrees is an effective and simple method to reduce blood loss after TKA, and contributes to reduction of the dosage of analgesic drugs in the early postoperative period. The routine application of the present protocol also did not increase medical costs and length of hospital stay after TKA.
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