Rehmannia glutinosa extract activates endothelial progenitor cells in a rat model of myocardial infarction through a SDF-1 α/CXCR4 cascade
Authors: Yu-Xia Zhao
Yun-Fang Liu
Wen-Wu Bai
Ying-Bin Wang
Fang-Fang Yan
Xiao-Ting Lu
Bo Wang
Journal: PLoS ONE (2013)
Discipline: Multidisciplinary
Keywords: Endothelial progenitor cells; Rehmannia glutinosa extract; myocardial infarction; angiogenesis; CD133
Affiliations: Key Laboratory of Cardiovascular Remodeling and Function Research, Shandong University, Jinan, Shandong, China.

Abstract:  Objectives: Endothelial progenitor cells (EPCs) can be used to repair tissues after myocardial infarction (MI) but EPC activators have adverse reactions. Rehmannia glutinosa is a herb used in traditional Chinese medicine, which can promote bone-marrow proliferation and protect the ischemic myocardium. We investigated the effects of Rehmannia glutinosa extract (RGE) on EPCs in a rat model of MI. Methods: A total of 120 male Wistar rats were randomized to 2 groups (n=60 each) for treatment: high-dose RGE (1.5 g·kg(-1)·day(-1) orally) for 8 weeks, then left anterior descending coronary artery ligation, mock surgery or no treatment, then RGE orally for 4 weeks; or normal saline (NS) as the above protocol. The infarct region of the left ventricle was assessed by serial sectioning and morphology. EPCs were evaluated by number and function. Protein and mRNA levels of CD133, vascular endothelial growth factor receptor 2 (VEGFR2), chemokine C-X-C motif receptor 4 (CXCR4), stromal cell-derived factor-1α (SDF-1α) were measured by immunohistochemistry, Western blot and quantitative PCR analysis. Results: RGE significantly improved left ventricular function, decreased the ischemic area and the apoptotic index in the infarct myocardium, also decreased the concentration of serum cardiac troponin T and brain natriuretic peptide at the chronic stage after MI (from week 2 to week 4). RGE increased EPC number, proliferation, migration and tube-formation capacity. It was able to up-regulate the expression of angiogenesis-associated ligand/receptor, including CD133, VEGFR2 and SDF-1α/CXCR4. In vitro, the effect of RGE on SDF-1α/CXCR4 cascade was reversed by the CXCR4 specific antagonist AMD3100. Conclusion: RGE may enhance the mobilization, migration and therapeutic angiogenesis of EPCs after MI by activating the SDF-1α/CXCR4 cascade. 

Retracted: Yes

PubPeer comments:
 This article has a note from June 2013 from the PLOS ONE editorial team about concerns over Figures 5, 6, and 7.  The PLOS ONE editorial team has been alerted to concerns over Figures 5, 6 and 7 in this article; the authors have been approached about these concerns and the data for the three figures are being evaluated. A notification will be posted on the article once the follow-up is completed in relation to the concerns raised. Here are these concerns - Figure 5A appear to show areas of overlap. ![file] , 
 Figure 6A appears to show areas of overlap between the top 2 photos. Show with blue boxes. ![file] , 
 Figure 6c appears to show multiple bands that look very similar to each other. Shown with red and green boxes. ![file] , 
 Figure 7 appears to show multiple bands that look very similar to each other. ![file] , 
 In addition to the concerns posted in 2013, there appears to be an area of overlap in Figure 2A. Marked with pink boxes: ![file] , 
 2019 retraction notice. https: journals.plos.org plosone article?id=10.1371 journal.pone.0217149 Following publication of this article [1], concerns were raised about possible duplication of images within Figures 2, 5, 6 and 7. Specifically, In Figure 2A there is a region of partial overlap between the NS-b and RGE-b panels. In Figure 5A the VEGFR2 NS-b panel and the VEGFR2 RGE-b panel appear similar; there is a region of partial overlap between the CD133 NS-b panel and the CD133 RGE-b panel. In Figure 6A there is a region of partial overlap between the NS-b and RGE-b panels. In Figure 6C the u03b2-actin western blot bands for NS-m, NS-MI, and RGE-MI have a similar appearance. The CXCR4 and SDF-1 bands for RGE-MI have a similar appearance. In Figure 7, the actin bands for 10 and 25 u03bcg ml in 7B have a similar appearance; the CXCR4 band for 25 u03bcg ml in 7B has a similar appearance to the actin band labelled C in 7C; the actin band for AMD in 7B has a similar appearance to the CXCR4 band for 72h in 7C; in 7C, the actin band for 6h and the CXCR4 band for 12h have a similar appearance; and the actin and CXCR4 bands for 24h have a similar appearance in 7C. In Figure 7D, the two left-hand histograms are duplicates. The authors have stated that errors were introduced at the stage of revising the manuscript. In follow up to the concerns raised, the authors provided the uncropped images underlying the above panels. They also provided replacement immunohistochemistry images and replicate uncropped immunohistochemistry images from all experimental animals to address the concerns raised regarding Figures 2, 5, and 6, a replacement histogram for Figure 7D, and replacement western blots for Figures 6 and 7. The PLOS ONE Editors evaluated the information and data provided and consulted with a member of the Editorial Board. Partial overlap in immunohistochemistry images was noted between tissue samples derived from different treatment groups, according to figure labels, and this concern could not be resolved by examination of the uncropped image files. Additionally, the evaluation suggested that incorrect western blot bands were used in the published figures for Figure 6C u03b2-actin bands and the SDF-1u03b1 RGE-MI band; Figure 7B the actin band for 10 u03bcg ml; and Figure 7C the actin bands for 6h, 12h, and 24h, and the CXCR4 bands for C, 12h, 24h, and 72h. Regarding the western blot methodology, the authors clarified that protein expression was normalized to actin levels; however, actin samples were run on different blots. For Figures 6 and 7, individual representative bands were taken from several different blots in the original published figures. The authors provided alternative continuous blots in support of their findings (in which all bands for the figure were present on adjacent lanes in the same blot, with a corresponding separate continuous blot for the actin controls). These alternative blots were carried out during the original study and form part of the underlying data for the quantifications reported in the charts in Figures 6D and 7D-E. The PLOS ONE Editors acknowledge that the authors identified inaccuracies in some of the images listed and requested corrections for those both prior to and shortly after publication of the article, and we regret that these concerns were not addressed earlier. In light of concerns about the reliability of the reported data, figure preparation, and conclusions, the PLOS ONE Editors retract this article. Y-BW, Y-FL, X-TL, F-FY, BW, W-WB, Y-XZ did not agree with retraction. Reference 1. Wang Y-B, Liu Y-F, Lu X-T, Yan F-F, Wang B, Bai W-W, et al. Rehmannia Glutinosa Extract Activates Endothelial Progenitor Cells in a Rat Model of Myocardial Infarction through a SDF-1 u03b1 CXCR4 Cascade. PLoS ONE. 2013;8(1): e54303. https: doi.org 10.1371 journal.pone.0054303 pmid:23349848 ,