Abstract
BackgroundMesenchymal stem cells (MSCs) have great potential for the repair and regeneration of bone fracture, but their optimal origins remain controversial.MethodsBone marrow-MSCs (BM-MSCs) and bone-bone marrow-MSCs (B-BM-MSCs) were isolated from 12 SD rats, and the morphology, MSC-associated markers, and proliferative capacity of these cells were compared using an inverted microscope, flow cytometry, and CCK-8 assays, respectively. After 14 days of osteoblastic induction, osteoblast phenotypes were detected by ALP and calcium nodule staining, and the expression of BMP-2 and TGF-β1 was observed by western blotting. Then, the rat tibia fracture model was established with 3 groups (n = 6 per group), the control, BM-MSC, and B-BM-MSC groups. Computed tomography (CT) imaging was performed to evaluate fracture healing at weeks 2, 4, and 6. Finally, the fractured bones were removed at weeks 4 and 6, and HE staining was performed to evaluate fracture healing.ResultsAlthough the 2 types of MSCs shared the same cellular morphology and MSC-associated markers, B-BM-MSCs had a higher proliferative rate than BM-MSCs from day 9 to day 12 (p < 0.05), and the expression levels of ALP and calcium were obviously higher in B-BM-MSCs than in BM-MSCs after osteogenic induction (p < 0.01 and p < 0.001, respectively). Western blot results showed that the expression levels of BMP-2 and TGF-β1 in B-BM-MSCs were higher than in BM-MSCs before and after osteogenic induction (p < 0.01). In the animal experiments, CT imaging and gross observation showed that B-BM-MSCs had a greater capacity than BM-MSCs to promote fracture healing, as the Lane-Sandhu scores of B-BM-MSCs at weeks 4 and 6 after operation (3.00 ± 0.81 and 9.67 ± 0.94, respectively) were higher than those of BM-MSCs (1.33 ± 0.47 and 6.67 ± 1.25, respectively; both p < 0.05). The HE staining results further supported this conclusion.ConclusionsTaken together, our study results proved that MSCs obtained by co-culturing the bone and bone marrow from SD rats had better proliferative, osteogenic differentiation, and fracture healing capacities than BM-MSCs, perhaps suggesting a novel way to obtain MSCs for bone tissue repair.
Highlights
Fracture is a common surgical complication that is expensive to treat and has negative effects on individuals and society
Taken together, our study results proved that Mesenchymal stem cells (MSCs) obtained by co-culturing the bone and bone marrow from Sprague Dawley (SD) rats had better proliferative, osteogenic differentiation, and fracture healing capacities than BMMSCs, perhaps suggesting a novel way to obtain MSCs for bone tissue repair
For MSCs derived from the bone marrow (BM-MSCs), the bone marrow has a small number of MSCs and their osteogenic potential is weaker than that of bone MSCs (B-MSCs) [11, 12]
Summary
Fracture is a common surgical complication that is expensive to treat and has negative effects on individuals and society. The available sources of MSCs are the umbilical cords, bone marrow, dental pulp, bone, adipose, et cetera. B-MSCs can be used as important seed cells for promoting bone regeneration, large amounts of the bone isolated from the body would cause serious secondary damage, severely limiting its clinical application [13, 14]. Other approaches to MSC acquisition face challenges in sourcing, tumorigenicity control, osteogenic potential, et cetera [15, 16]. It is necessary to develop a new approach to extract MSCs with great proliferative capacity and osteogenic potential from various sources while causing minimal damage to the body. Mesenchymal stem cells (MSCs) have great potential for the repair and regeneration of bone fracture, but their optimal origins remain controversial
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