Optimal technique for canine mesenchymal stem cells labeling with novel SPIO, MIRB?: for MRI detection of transplanted stem cells canine stroke model

Background: Cell-based therapy has emerged as a promising avenue for post-stroke recovery. A significant challenge lies in tracking the distribution and engraftment of transplanted cells within the target cerebral tissue. To address this, we turn to the potential of Brain MRI detection of mesenchymal stem cells (MSCs), achieved by labeling these cells with superparamagnetic iron oxide (SPIO). This is the first report of a technique to label canine MSCs using a commercially available SPIO, Molday ION Rhodamine B (MIRB), to optimize both viability and labeling efficacy for transplantation purposes." Method: Canine MSCs were incubated with addition of different MIRB concentration from 0, 10, 20, 30 mu g Fe/ml. The cellular uptake of MIRB was confirmed through the analysis of fluorescent images and flow cytometry. The morphological characteristics of MSCs were assessed via microscopic visualization. Cellular viability was evaluated using both a cellometer and flow cytometry. Result: Fluorescent microscopic images of all MIRB incubated MSCs groups show >70% labeled cells with homogenous signal intensity. Notably, the morphology of MSCs remained unaltered in the 10 mu g Fe/ml group compared to the control group. Furthermore, among the labeled groups, the 10 mu g Fe/ml concentration exhibited the highest viability when assessed using two different flow cytometry methods (95.3%, p < 0.05). Conclusion: This study successfully labels canine MSCs with MIRB. The optimal concentration of 10 mu g Fe/ml demonstrates optimal viability, labeling efficacy, and preserved cellular morphology.