BACKGROUND:MicroRNAs (miRNAs) play a crucial role in regulating diverse biological processes, including drug resistance. We investigated the potential roles of the miR-29 family in methotrexate (MTX) resistance in osteosarcoma. MATERIAL AND METHODS:T...

Mesenchymal stem cells (MSCs) have drawn great attention because of their therapeutic potential. It has been suggested that intra‐venous infused MSCs could migrate the site of injury to help repair the damaged tissue. However, the mechanism for MSC migration is still not clear so far. In this study, we reported that hypoxia increased chemotaxis migration of MSCs. At 4 and 6 hours after culturing in hypoxic (1% oxygen) conditions, the number of migrated MSCs was significantly increased. Meanwhile, hypoxia also increased the expression of HIF‐1α and SDF‐1. Using small interference RNA, we knocked down the expression of HIF‐1α in MSCs to study the role of HIF‐1α in hypoxia induced migration. Our data indicated that knocking down the expression of HIF‐1α not only abolished the migration of MSCs, but also reduced the expression of SDF‐1. Combining the results of migration assay and expression at RNA and protein level, we demonstrated a novel mechanism that controls the increase of MSCs migration. This mechanism involved HIF‐1α mediated SDF‐1 expression. These findings provide new insight into the role of HIF‐1α in the hypoxia induced MSC migration and can be a benefit for the development of MSC‐based therapeutics for wound healing.

Studies have shown that lumbar disc herniation, degenerative lumbar instability, and other degenerative lumbar spinal diseases are often secondary to disc degeneration. By studying the intervertebral disc, researchers have clarified the pathological changes involved in intervertebral disc degeneration but have ignored the roles of biomechanical factors in the development of disc degeneration. This study aims to investigate the relationships among the location, scope, and extent of lumbar disc degeneration and sagittal spinal-pelvic parameters. A retrospective analysis was performed on the clinical data of 284 patients with lumbar degenerative disc diseases (lumbar disc herniation and degenerative lumbar instability) from January 2013 to December 2016. Statistics were calculated for the following: (1.) patients’ general information: name, sex, age, height, and weight. (2.) Measurements of sagittal parameters from total spinal radiographs: thoracic kyphosis (TK), Lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), sagittal vertical axis (SVA), T1 tilt angle (TA), and T1 pelvic angle (TPA). (3.) Location, scope, extent, and overall degree of lumbar disc degeneration. Parameters were analyzed in groups by sex, PI, and SVA, and a correlation analysis was performed for the location, scope, extent, and overall degree of lumbar intervertebral disc degeneration with 8 spinal-pelvic sagittal parameters. The mean ages of the male and female patient groups were 59.00 and 53.28 years old, respectively (P < 0.05). The PT, location, scope, and overall degree of degradation were significantly different between the sexes (P < 0.05). Linear correlation analysis results showed that the overall degree and extent of degradation (r = 0.788, P < 0.01), LL and SS (r = 0.737, P < 0.01), PI and PT (r = 0.607, P < 0.01), and TPA and PT (r = 0.899, P < 0.01) were strongly correlated. The location values were 4.08 ± 0.72 in patients with PI≤50° and 3.62 ± 0.94 in patients with PI> 50° (P = 0.018). Different SVASVA groups differed in their overall degree of degeneration (P = 0.002). The location of lumbar intervertebral disc degeneration is affected by spinal-pelvic sagittal morphology. Populations with small PI values tend to exhibit degeneration at the L4/5 and L5/S1 discs, and populations with large PI values tend to exhibit degeneration at the L3/4 and L4/5 discs. The SVA value and the overall degree of lumbar disc degeneration are positively correlated.