Cryopreserved Mesenchymal Stem Cells Stimulate Regeneration in an Intervertebral Disc

BACKGROUND Degenerative diseases are a medical, social, and economic problem worldwide. The most significant factors predisposing the development of degenerative changes in intervertebral discs are a low density and poor biosynthetic potential of the cells. Therefore, stem cell therapy in this case should show high clinical efficiency. METHODS The research aim was to evaluate the regenerative potential of cryopreserved mesenchymal stem cells (MSCs) upon degenerative changes in intervertebral discs. Rats with simulated degenerative damage of the intervertebral disc Co6-Co7 were administrated with 0.5 × 10⁶ of either native or cryopreserved cells on a collagen sponge to the defect area. The results of experiments were histomorphometrically evaluated on the 30th, 60th, and 90th days after treatment. RESULTS The restoration of tears, clefts, and collagen fiber fragmentations was noted on the 60th and 90th day after administration of native and cryopreserved MSCs respectively. An increase in fibrochondrocyte density got ahead of the annulus fibrosus height recovery. In the control group without treatment the regeneration was hardly observed. CONCLUSION The use of MSCs promotes the restoration of the degenerated intervertebral disc. Cryopreserved MSCs have a "lag" therapeutic effect at the early stages, but show similar results to the native analogue on the 90th day after administration.