Influence of Hypoxia in the Intervertebral Disc on the Biological Behaviors of Rat Adipose- and Nucleus Pulposus-Derived Mesenchymal Stem Cells

Abstract

Adipose-derived mesenchymal stem cells (ADMSCs) and nucleus pulposus-derived mesenchymal stem cells (NPMSCs) are two cell candidates for cell-based therapies for intervertebral disc (IVD) regeneration. However, little work has been done to determine the influence of hypoxia in the IVD on the biological behaviors of ADMSCs and NPMSCs. This study aimed to investigate the viability, proliferation and differentiation of rat ADMSCs and NPMSCs in the hypoxic environment of IVD in vitro. ADMSCs and NPMSCs isolated from 6 SD rats were cultured under normoxia (20% O₂) and hypoxia (2% O₂) mimicking the standard condition and hypoxic environment of the IVD for 14 days. Cell viability was determined by the annexin-V-FITC/propidium iodide double-staining assay and cell proliferation was measured by MTT assay. The expression of hypoxia-inducible factor-1α, glucose transporter (GLUT)-1, GLUT-3 and vascular endothelial growth factor-A at the mRNA level was examined by RT-PCR. In cells cultured in three-dimensional micromass and differentiation medium, aggrecan, collagen-II and Sox-9 expression at mRNA and protein levels were examined by RT-PCR and Western blot. Hypoxia inhibited the viability and proliferation of both ADMSCs and NPMSCs, but promoted the chondrocytic differentiation of ADMSCs and NPMSCs. Compared to ADMSCs, NPMSCs showed greater viability, proliferation and chondrocytic differentiation under hypoxia. In conclusion, hypoxia in the IVD had a significant impact on the viability, proliferation and chondrocytic differentiation of ADMSCs and NPMSCs. NPMSCs exhibited more potent biological activity than ADMSCs in the hypoxic environment of the IVD and may represent another candidate for cell-based therapy for IVD regeneration.

Comparison of biological characteristics of nucleus pulposus mesenchymal stem cells derived from non-degenerative and degenerative human nucleus pulposus

“…Certain studies have reported that these stem cells lack viability, proliferation and matrix biosynthesis under conditions resembling the IVD microenvironment, which negatively influences the biological and metabolic vitality of stem cells and impairs their repair potential (16,17). In recent years, increasing evidence supported the existence of nucleus pulposus MSCs (NPMSCs) in the nucleus pulposus (18)(19)(20)(21)(22)(23)(24). They possess a similar capacity of chondrogenic differentiation to that of BMSCs (18) and have better adaptability to the harsh IVD microenvironment than ADMSCs (24).…”

“…This suggests that NPMSCs may be a good candidate cell for IVD regeneration by cell therapy. Previous studies have proved that NPMSCs can be isolated from normal and degenerative nucleus pulposus (18)(19)(20)(21)(22)(23)(24). However, the biological properties of stem cells are crucial for the regenerative effects of cell therapy.…”

The Influence of Hyperosmolarity in the Intervertebral Disc on the Proliferation and Chondrogenic Differentiation of Nucleus Pulposus-Derived Mesenchymal Stem Cells

“…Our previous studies [Li et al, 2013;Han et al, 2014] and many others [Blanco et al, 2010;Wu et al, 2017;Molinos et al, 2018] have demonstrated that the IVD itself contains MSCs. Blanco et al [2010] identified human NP-derived (NP)-MSCs from human degenerative discs, and found that these cells fulfilled nearly all the morphological, immunophenotypical, and differentiation criteria described by the International Society of Cell Therapy for MSCs.…”

The potential of chondrogenic pre-differentiation of adipose-derived mesenchymal stem cells for regeneration in harsh nucleus pulposus microenvironment

“…The condition in degenerated disc is characterized by low oxygen tension, limited nutrition, acidic pH, and high osmolarity, which may negatively influence the function or even survival of any implanted cells. 4,6,[12][13][14] To overcome harsh condition in disc, previous literatures proposed pre-conditioning cells before implantation 6 and appropriately differentiated cells could survive and synthesize matrix in situ. 10 With this in mind, we designed this study to investigate the potential effect of chondrogenic pre-differentiation on the regeneration of adipose-derived mesenchymal stem cells (ADSCs) in a harsh IVD-like condition.…”