Byline: Feng. Yan, Wei. Yue, Yue-lin. Zhang, Guo-chao. Mao, Ke. Gao, Zhen-xing. Zuo, Ya-jing. Zhang, Hui. Lu
In this study, we successfully constructed a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffold in vitro, transplanted either the composite or bone marrow mesenchymal stem cells alone into the ischemic area in animal models, and compared their effects. At 14 days after co-transplantation of bone marrow mesenchymal stem cells and the hitosan-collagen scaffold, neurological function recovered noticeably. Vascular endothelial growth factor expression and nestin-labeled neural precursor cells were detected in the ischemic area, surrounding tissue, hippocampal dentate gyrus and subventricular zone. Simultaneously, a high level of expression of glial fibrillary acidic protein and a low level of expression of neuron-specific enolase were visible in BrdU-labeled bone marrow mesenchymal stem cells. These findings suggest that transplantation of a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffold has a neuroprotective effect following ischemic stroke.
The central nervous system can activate the proliferation, migration and differentiation of bone marrow mesenchymal stem cells (BMSCs) through an innate brain repairing and/or reshaping (brain plasticity) mechanism to recover the stability of the internal environment and to promote the repair of neurological function (Bjorklund and Lindvall, 2000). Our team observed local proliferation in the subventricular zone from the first day after damage in the adult rat models of brain injury, which reached a peak on day 7 (Zhang et al., 2006). However, endogenous neural stem cells in the brain with poor ability to migrate and differentiate into functional neurons only proliferated during a certain period after brain tissue damage (Li et al., 2015).
Some studies have shown that multiple hormone and neurotrophic factors secreted by BMSCs can promote the growth, differentiation and protection of endogenous neural precursor cells, which contribute to nerve repair and regeneration (Cantinieaux et al., 2013; Xia et al., 2013). Chitosan-collagen is a common tissue-engineered material for scaffolds and has been widely used in transplantation because of its advantages, including strong biodegradability, low antigenicity, good biocompatibility and lack of pyrogen reaction (Dash et al., 2011; Ji et al., 2011). In this study, we sought to observe the effects of transplantation of BMSCs and an absorbable chitosan-collagen porous scaffold on ischemic stroke.
Materials and Methods
Separation, purification, identification and labeling of BMSCs
Six healthy male Wistar rats aged 3 weeks and weighing 100 g were purchased from the Environment Institute of the Academy of Military Medical Sciences in China (License No. SCXK (Jing) 2012-003). The experiment was conducted in the Center Laboratory of Shaanxi Provincial People's Hospital of China. The whole bone marrow adherent culture method (Song et al., 2014) was used to obtain primary cultured BMSCs. Briefly, after rats were sacrificed under anesthesia with an intraperitoneal injection of chloral hydrate (0.4 g/kg; Sigma), the femur and tibia were separated under sterile conditions, and the medullary canal was rinsed with serum-free Dulbecco's modified Eagle's medium/F12 (DMEM/F12) medium (HyClone, Waltham, MA, Amityville, NY, USA), collected in sterile tubes and centrifuged. Subsequently,...