Anterograde and retrograde tracing with high molecular weight biotinylated dextran amine through thalamocortical and corticothalamic pathways

Biotinylated dextran amine (BDA) has been used for neural pathway tracing in the central nervous system for many decades, in which high molecular weight BDA appeared to be transported predominantly in the anterograde direction and less in the retrograde direction. In the current study, we reexamined the properties of neural labeling with high molecular weight BDA through a reciprocal neural pathway between thalamus and somatosensory cortex. After injection of BDA into the ventral posteromedial nucleus of thalamus (VPM) in the rat, the BDA labeling was sequentially examined on somatosensory cortex at 3, 5, 7, 10, and 14 survival days. Both of anterogradely labeled axonal terminals and retrogradely labeled neuronal cell bodies were observed simultaneously on the somatosensory cortex. With the increasing of survival times after injection, morphological changes occurred on the labeled axonal arbors and neuronal dendrites, in which the high quality of BDA labeling appeared on the tenth survival day. These results indicate that high molecular weight BDA is not only a sensitive anterograde tracer but also an excellent retrograde marker to be used for tracing through thalamocortical and corticothalamic pathways. And the detailed structure of neural labeling with BDA similar to Golgi‐like resolution can be obtained at optimal survival times of animals after the injection of high molecular weight BDA.     

Transplantation of BMP-7 gene-transfected bone marrow mesenchymal stem cells for the treatment of spinal cord injury in rats

Background: Spinal cord injury (SCI) is a serious traumatic disease of the central nervous system, and there is currently no effective treatment for SCI because of its complicated pathophysiology. Bone marrow mesenchymal stem cells (BMSCs) have multidirectional differentiation abilities. Our study aims to explore the effects of bone morphogenetic protein 7 (BMP-7)-modified BMSCs transplantation on the repair of SCI in rats. Methods: In this study, a rat spinal cord injury model was established with the modified Allen method. Then, BMSCs transfected with the BMP7 gene were transplanted to treat the spinal cord injury in rats. Forty Sprague-Dawley rats were randomly divided into the sham operation group (sham group), spinal cord injury group (model group), BMSC treatment group (BMSC group) and LV-BMP7-BMSC treatment group (LV-BMP7-BMSC group). The Basso, Beattie, and Bresnahan (BBB) score was used to evaluate the recovery of hindlimb function in the rats. The levels of neurofilament protein NF-200 (NF-200) and glial fibrillary acidic protein (GFAP) were detected by immunofluorescence, RT-PCR and Western blotting. Results: At 14 d, 21 d, and 28 d after treatment, the BBB score of the rats in the LV-BMP7-BMSC group was higher than that of the rats in the model group and BMSC group. The results showed that NF-200 was expressed at the local spinal cord injury site. Compared with that of the sham group, the NF-200 expression level of the BMSC group and LV-BMP7-BMSC group was increased (P < 0.05). The results showed that the mRNA expression levels of NF-200 in the spinal cord tissue of the BMSC group and LV-BMP7-BMSC group were increased compared with those of the sham group (P < 0.05). The western blotting results further confirmed the PCR results. Conclusion: BMP-7 gene-modified BMSC transplantation can promote the repair of spinal cord functions after SCI in rats.