AMD3100 inhibits the migration and differentiation of neural stem cells after spinal cord injury
It was reported that CXCR4 signaling played an important role in the migration and differentiation of endogenous neural stem cells after spinal cord injury (SCI). However, the molecular mechanism of it is still unclear. Here, we established a model of SCI in rats and AMD3100 was used to treat them. The rats were then sacrificed and the injured spinal cord specimens were harvested. Additionally, the neural stem cells (NSCs) line was culture and treated with AMD3100 in vitro. Results showed the locomotor function of SCI rats was worse after treated with AMD3100. And the expression levels of Nestion in neural stem cells and β-tubulin in neuron cells were significantly increased in the injured spinal cord, which can be inhibited by the CXCR4 antagonist of AMD3100. Additionally, the expression of β-catenin and phosphorylase β-catenin protein was significantly down regulated by AMD3100. In vitro, the NSCs proliferation ability was inhibited and the migration was decreased after treated with AMD3100. Also, the expression of Nestion, β-tubulin, β-catenin and phosphorylase β-catenin protein was significantly decreased in AMD3100 group comparing with untreated group. Taken together, this study suggested that AMD3100 could inhibit the migration and differentiation of endogenous neural stem cells in rats with SCI. The mechanism of it maybe that AMD3100 could down regulate of SDF-1/CXCR4 by targeting β-catenin signaling pathway.In order to investigate whether SCI could evoke the activity of SDF-1/CXCR4 axis in rat, the expression of SDF-1 protein was detected by immunohistochemstry (IHC) assay. The results showed SDF-1 protein was expressed in nuclei of neural stem cell and was significantly higher in SCI group than those in sham group (Fig. 1). It suggested that SCI could evoke the activity of SDF-1/CXCR4 axis.Adult female Sprague-Dawley (SD) rats (weighting 220–250 g) were obtained from the laboratory animal science centre of the Nanchang University (Nanchang, China) for the experiments. All the procedures and protocols were approved by the Ethics Committee on Animal Experiments of the first affiliated hospital of Nanchang university. The rats were housed 4 per cage with free access to food and water and maintained in a suitable environment at 25 °C and a 12 hour light/dark cycle. All animal procedures and maintenance were conducted in accordance with the institutional guidelines of the university. Rats were anesthetized via an intraperitoneal injection of 2% pentobarbital (2 ml/kg). And then the spinous process and vertebral lamina were removed to expose a circular region of dura at the thoracic 10 vertebral level28. An incomplete SCI was made by dropping a 10 grams metal rod onto the dura from a height of 25 mm29. Rat’s bladders were manually emptied three times a day until the reflex bladder emptying function was restored. Thirty-six rats were randomly assigned into 3 groups (n = 12/group): i) the sham-operated group; ii) the untreated group (intraperitoneal injection of 5 mg/kg PBS for five days); iii) the AMD3100 group (intraperitoneal injection of 5 mg/kg AMD3100 for five days). Rats were sacrificed on the 7th, 14th, 21th and 28th day after surgery, respectively.This work is supported by the National Natural Science Foundation of China (No. 81560435) and the Natural Science Foundation of Jiangxi Province, PR. China (No. 20142BAB215046).The authors declare no competing financial interests.Jia-Ming Liu and Kai Zhao contributed equally to this work.Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.