Statement of Retraction We, the Publisher of the journal Bioengineered , have retracted the following article: Zhi Peng et al - Exosomes from bone marrow mesenchymal stem cells promoted osteogenic differentiation by delivering miR-196a that targeted Dickkopf-1 to activate Wnt/β-catenin pathway , Bioengineered (2021) (DOI: https://www.10.1080/21655979.2021.1996015) Since publication, significant concerns have been raised about the integrity of the data and reported results in the article. When approached for an explanation, the authors checked their data and confirmed there are fundamental errors present. Therefore, they have agreed to the retraction of this article. The authors apologise for this oversight. We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.

ABSTRACT. Lumbar intervertebral disc degeneration is induced by multiple factors, but few studies have examined the effects of aquaporins on this process. We compared the expression levels of aquaporins 1 and 3 in normal and degenerative lumbar intervertebral discs. Fifteen normal and 15 degenerative lumbar intervertebral disc tissues were excised from lumbar burst fracture patients during orthopedic operations at the Dali College subsidiary hospital. Tissues were stained with hematoxylineosin and the expression levels of aquaporins 1 and 3 were measured by immunohistochemistry. Hematoxylin-eosin-staining results illustrated that the structures of the intervertebral disc tissues from the control group were clear, with distinct collagen fiber shapes and slight edema but without mucoid degeneration. Structures of the intervertebral disc tissues from the disease group were obscure and disordered with hyperplastic collagen fibers and tissues of severe inflammatory edemas with necrosis mucoid degeneration. Immunohistochemistry results demonstrated that the average absorbances of aquaporins 1 and 3 in the disease group were significantly lower than those in the control group (P < 0.01), suggesting that the reduction of aquaporins 1 and 3 may be a factor resulting in lumbar intervertebral disc degeneration.

Background Osteoporosis seriously disturbs the life of people. Meanwhile, inhibition or weakening of osteogenic differentiation is one of the important factors in the pathogenesis of osteoporosis. It was reported that miR-27a-3p reduced the symptoms of osteoporosis. However, the mechanism by which miR-27a-3p in osteogenic differentiation remains largely unknown. Methods To induce the osteogenic differentiation in MC3T3-E1 cells, cells were treated with osteogenic induction medium (OIM). RT-qPCR was used to evaluate the mRNA expression of miR-27a-3p and CRY2 in cells. The protein levels of CRY2, Runt-related transcription factor 2 (Runx2), osteopontin (OPN), osteocalcin (OCN) and the phosphorylation level of extracellular regulated protein kinases (ERK) 1/2 in MC3T3-E1 cells were evaluated by western blotting. Meanwhile, calcium nodules and ALP activity were tested by alizarin red staining and ALP kit, respectively. Luciferase reporter gene assay was used to analyze the correlation between CRY2 and miR-27a-3p. Results The expression of miR-27a-3p and the phosphorylation level of ERK1/2 were increased by OIM in MC3T3-E1 cells, while CRY2 expression was decreased. In addition, OIM-induced increase of calcified nodules, ALP content and osteogenesis-related protein expression was significantly reversed by downregulation of miR-27a-3p and overexpression of CRY2. In addition, miR-27a-3p directly targeted CRY2 and negatively regulated CRY2. Meanwhile, the inhibitory effect of miR-27a-3p inhibitor on osteogenic differentiation was reversed by knockdown of CRY2 or using honokiol (ERK1/2 signal activator). Furthermore, miR-27a-3p significantly inhibited the apoptosis of MC3T3-E1 cells treated by OIM. Taken together, miR-27a-3p/CRY2/ERK axis plays an important role in osteoblast differentiation. Conclusions MiR-27a-3p promoted osteoblast differentiation via mediation of CRY2/ERK1/2 axis. Thereby, miR-27a-3p might serve as a new target for the treatment of osteoporosis.

Background Owing to neurite promoting, antioxidant and anti-inflammatory effects of Euxanthone (Eux), the investigation was aimed to probe the neuroprotective efficacy of Eux against traumatic spinal cord injury (t-SCI) in rats and whether Eux can improve neuropathic function in t-SCI. Method Sprague-Dawley (SD) rats were randomized in – Sham, t-SCI, Eux30, and Eux60 (t-SCI + 30 and 60 mg/kg respectively). Animals with compression force-induced t-SCI were subjected to estimation of locomotor functions. Spinal cord water content and Evans blue (EB) effusion were determined for quantifying edema and intactness of the spinal cord. Oxidative stress and immunochemical markers were quantified by ELISA and western blotting. Results Findings revealed that Eux60 group animals had greater Basso, Beattie, and Bresnahan (BBB) and (incline plane test) IPT score indicating improved locomotor functions. There was a reduction in the spinal edema and water content after Eux treatment, together with lowering of oxidative stress markers. The expression of IL-6, IL-12, IL-1β, caspase-3, RANKL, TLR4, NF-κB, p-38, PI3K, and Akt in spinal cord tissues of t-SCI-induced rats was lowered after Eux treatment. Conclusion Overall, the investigation advocates that Eux attenuates t-SCI and associated inflammation, oxidative damage, and resulting apoptosis via modulation of TLR4/NF-κB/p38 and PI3K/Akt signaling cascade.

Objective To retrospectively analyze if the use of topical intraoperative vancomycin powder reduces deep surgical site infection (DSSI) after posterior lumbar interbody fusion. Methods All spinal surgeries for lumbar degenerative disease and underwent posterior fixation interbody fusion between January 2013 and December 2018 were reviewed. A total of 891 patients were included, of which 527 patients (treatment group) received intraoperatively topical vancomycin powder; the others were served as control group. The primary outcomes were the overall incidence of DSSI and the effect of vancomycin on its development. The secondary outcome was risk factors for DSSI. Data on the baseline characteristics, postoperative complications, perioperative risk factors, and one-year postoperative prognoses were extracted from the medical records. Results A total of 20 patients met the diagnostic criteria for DSSI (2.24%), of which 7 patients (1.33%) in the treatment group and 13 patients (3.57%) in the control group. There was a significant difference in the incidence of DSSI between the groups ( P = 0.026). Multivariate logistic regression analysis with stepwise backward elimination showed that the local use of vancomycin powder was an independent protective factor for DSSI (odds ratio ( OR ): 0.25, P = 0.01), whereas high body mass index (BMI) ( OR : 1.21, P = 0.005), drinking ( OR : 5.19, P = 0.005), urinary tract infections ( OR : 4.49, P = 0.021), diabetes mellitus ( OR : 4.32, P = 0.03), and blood transfusions ( OR : 3.67, P = 0.03) were independent risk factors for DSSI. Conclusion The intraoperative usage of vancomycin powder could reduce effectively decreases the incidence of DSSI after posterior lumbar interbody fusion for degenerative lumbar diseases. High BMI, diabetes mellitus, drinking, and urinary tract infections were independent risk factors for DSSI, whereas the local use of vancomycin protected against these factors.