RETRACTED ARTICLE: Effects of BDNF-Transfected BMSCs on Neural Functional Recovery and Synaptophysin Expression in Rats with Cerebral Infarction
Authors: Yi Yao
Chunlin Wang
Jiachuan Liu
Yongming Zhang
Jinbiao Wang
Binghui Qiu
Journal: Molecular Neurobiology (2017)
Discipline: NEUROSCIENCE & BEHAVIOR
Keywords: Bone marrow mesenchymal stem cells; Brain-derived neurotrophic factor; Cerebral infarction; Flow cytometry; Immunohistochemistry
Affiliations: Department of Neurosurgery, No. 105 Hospital of PLA, No. 424 Changjiang West Road, Hefei, 230031, Anhui, People's Republic of China. ., Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, People's Republic of China., Department of Neurosurgery, No. 105 Hospital of PLA, No. 424 Changjiang West Road, Hefei, 230031, Anhui, People's Republic of China.

Abstract:  The purpose of this study was to investigate the effects of brain-derived neurotrophic factor (BDNF)-transfected bone marrow mesenchymal stem cells (BMSCs) on neural functional recovery and synaptophysin expression in rats with cerebral infarction (CI). A total of 120 healthy Sprague Dawley rats were randomly divided into sham group, control group, and model group. Craniotomy was conducted and neurological function defect scoring was used to verify the model. BDNF containing recombinant plasmid was transfected into rat BMSCs, which was verified by flow cytometry and Western Blot. After injection of the transfected BMSCs, neural functional recovery of the CI rats and synaptophysin expression were measured. After the CI rat model was established, magnetic resonance (MR) imaging, 2, 3, 5- triphenyl tetrazolium chloride (TTC) staining, and the neurological function defect scoring determined the success of the model. CD34 (-), CD45 (-), CD29 (+), and CD90 (+) cells detected showed that the obtained BMSCs have high purity. BDNF protein was highly expressed in the BMSCs successfully transfected with the recombinant plasmid. Balance beam walking score, rotating bar walking score, and screen test score were significantly lower, while synaptophysin expression was higher in the BDNF model group than those in the non-BDNF model group and sham group with time extension. BDNF can increase synaptic plasticity and neurogenesis and have a promotional role in neural functional recovery and synaptophysin expression in rats with CI. BDNF-transfected BMSCs may therefore have better treatment efficacy for CI clinically. 

Retracted: Yes

PubPeer comments:
 Figure 5E. T he figure legend says  Live imaging of all recipient mice . The main text states that  All mice were randomly divided into three groups, namely FMT_MM, FMT_HC, and PBS , but looking at the mice in Figure 5E that appears to be unlikely. The  FMT-HC group consisted of 3 male mice, the  PBS group of 5 female mice, and the  FMT_MM group of 3 male mice? It appears to be that the groups not only differed in size but also in sex ratios. That would be bad scientific practice. Could the authors please clarify why these group differed so much? ![file] , 
 Also, looking at the white spots on the bellies of some mice (not the nipples, or the front paws, but other spots), it appears that not all timepoint panels show the same mice. For example, in the FMT-HC group, the 3rd mice in the week 4, week 5, and week 6 panels all have unique white spots not visible in any other mouse. The same is true for the 3rd mouse in the PBS week 3 panel. Is there a biological reason that could explain these changing spots? Do the white spots move in these mice? Are they scars that magically heal within a week? , 
 #1 2 Dear Pub Peer, Thank you for raising the concern regarding the group differences. In fact, one of the reviewers asked the similar questions: how were in general the mouse experiments performed? Were all mice from a particular group cohoused in the same cage? Here are our answers. A key issue in the microbiota study involving experimental mice is the u201ccage effectu201d. To minimize the cage effect, the mice from different groups and different genders were kept in separate cages, and each cage contained five or six mice. At first, we used 5-6 mice each group to develop multiple myeloma (MM) via tail-vein injection of 5TGM1 MM cells. To better observe the tumor progression and survival of each group treated with different FMT, we prolonged the experiments to week 6 until we observed that the tumor burden became significant. As a result, at the end points, only 3 females left. We repeated the FMT experiment for twice with different genders and in separate cages and the results were reproducible. All the results were presented to the reviewer but only one set of results were presented in this paper, the rest of the data were provided as Additional file 13. With regard to the question for the 3rd mouse in the week 4, week 5, and week 6 panels all having unique white spots not visible in any other mouse, we carefully checked the original images of these mice. We found that in the process of living image, it is possible that we messed up the hair of some of these mice (when handling the mice, injecting drugs and collecting mice feces, etc.) and thus exposed their skin that formed a white spot as shown in the figure. The same is true for the 3rd mouse in the PBS week 3 panel. When the hair of mice was straightened, the hair covered the skin and the white spot disappeared. We hope this clarifies your concerns but if we can be of further assistance, please let us know. Wen Zhou ,