In Vivo Fluorescence Tracking of Bone Marrow Stromal Cells Transplanted into a Pneumatic Injury Model of Rat Spinal Cord

Abstract

Recent experimental studies have shown that bone marrow stromal cells (BMSC) differentiate into neural cells and reduce neurological deficits when transplanted into traumatized spinal cord. These findings have been derived primarily from histological analyses. We conducted a study directed chiefly at developing a non-invasive system for tracking BMSC transplanted into the spinal cord of living animals. In this study, we induced spinal cord injury (SCI) in rats with a pneumatic device. BMSC were harvested from transgenic mice expressing green fluorescence protein (BMSC-GFP), and were transplanted stereotactically into a control group of rats without SCI (n = 6) and a group with SCI (n = 3). At 2 and 4 weeks after transplantation, the dura mater was exposed and green fluorescence derived from the transplanted BMSC-GFP was observed. The distribution and differentiation of the transplanted cells were subsequently evaluated with immunohistochemistry. Green fluorescence could be detected around the transplantation site in three of six of the control rats. In all three rats subjected to SCI, green fluorescence was shown to spread from the site of BMSC-GFP injection toward the injury site, suggesting that the transplanted cells had migrated toward the lesion within the 4-week post-transplantation period. Histological evaluation suggested that the detected green fluorescence was emitted by cells that had distributed in the dorsal white matter, and demonstrated that some of the transplanted cells expressed neuronal or astrocytic markers. These results suggest the possibility of tracking BMSC transplanted into the spinal cord in living animals. Such noninvasive bioimaging techniques would be valuable for monitoring the fate of these transplanted cells and assessing the safety and efficacy of their transplantation.

Biological Features of Human Bone Marrow Stromal Cells (hBMSC) Cultured with Animal Protein-Free Medium—Safety and Efficacy of Clinical Use for Neurotransplantation

“…According to them, there would be no significant differences in their morphology among species. In fact, the hBMSC exhibit the morphology similar to the BMSC obtained from the rats and mice, when cultured with the conventional FCS-containing medium [5,8,21,22,31,33,34]. This study further confirms that there is no significant difference in their morphology between the hBMSC-FCS and hBMSC-PL (Fig.…”

“…Because of the limited regenerative capacity of central nervous system (CNS), the therapeutic potential of cell transplantation has been investigated in various pathological conditions of CNS, e.g., Parkinson's disease [1,2], cerebral infarction [3][4][5][6], spinal cord injury [7][8][9], traumatic brain injury [10][11][12], and so forth. To regenerate the injured CNS tissues, a variety of cell sources including neural progenitor/ stem cells [13,14], embryonic stem cells [15], and bone marrow stromal cells (BMSC) [16] have been considered as the candidates of donor cells for cell transplantation therapy.…”

Bone marrow-derived mesenchymal stromal cells for the repair of central nervous system injury

“…In vivo fluorescence tracking with GFP suggests that mouse MSCs transplanted into the rat spinal cord migrate towards the injury site within 4 weeks after transplant, and some of these cells express neuronal or astrocytic markers. 71 Functional improvement was also observed in a mouse model, either with 57 or without 72 expression of markers of neurons and astrocytes. Magnetic resonance tracking of implanted adult rat MSCs labeled with iron-oxide nanoparticles into the injured rat brain and spinal cord, either intracerebrally or i.v., demonstrated migration to the lesion site, a very small number of MSCs differentiated into neurons but not astrocytes, and the rats with spinal cord injury demonstrated functional recovery.…”

Effects of Differentiated Versus Undifferentiated Adipose Tissue-derived Stromal Cell Grafts on Functional Recovery After Spinal Cord Contusion

“…Reports of rat MSCs transdifferentiating into cells with neural phenotypes after being grafted into the injured CNS have led to controversy (Lu et al 2006;Mahmood et al 2004;Parr et al 2007;Yano et al 2005;Yoshihara et al 2006). In the present study, uADSCs failed to express neural markers in culture conditions, but a few uADSCs differentiated into neurons, but not astrocytes, in vivo, indicating that neural differentiation of uADSCs could occur in vivo, as a result of environmental factors.…”

“…Although the neural transdifferentiation of MSCs is currently controversial, some promising results have been achieved after grafting of differentiated MSCs into injured spinal cord and brain (Kamada et al 2005;Lu et al 2005;Ye et al 2007). On the other hand, undifferentiated MSCs have also been shown to express neural markers and provide therapeutic benefit after CNS injury (Hofstetter et al 2002;Lu et al 2006;Mahmood et al 2004;Yano et al 2005). Thus, some researchers have questioned the need for transdifferentiation of MSCs prior to the transplantation procedure (Vaquero and Zurita 2009).…”