Experimental Correction of Pathological Changes in the Intervertebral Disc Using Tissue Engineering

Abstract

To analyze the restoration of structure-metabolism relationships within the spinal segment in experimental model using tissue engineering method. Material and Methods. Correction of early stages of osteochondrosis induced in the experimental model was performed using 3D tissue-engineered chondral graft. The studies were conducted on eight adult mongrel dogs. The chondral graft was inserted into the bed of the removed nucleus pulposus of the L4-L5 intervertebral disc. The mechanism of correction involves restoration of the disc height, microcirculation and lymph drainage, and prevention of formation and development of herniations and neuro-vertebral conflict. Results. The intervertebral disc with a height equal to that of a healthy one was distinctly contoured on the X-ray in 1 month after transplantation of the 3D chondral graft. After 3 and 6 months the X-ray pattern did not change. Osteophytes developed at the edges. Histological assay showed that in 3 months the cartilage tissue was formed and it filled the bed of nucleus pulposus, being restricted by annulus fibrosus. Bone tissue did not differ from healthy specimens in structure. In 6 months the mature hyaline cartilage was formed in the region of nucleoplasty. Type II collagen and proteoglycans were observed in the matrix. The degree of regenerate differentiation is evidenced by the organized chondron-like structure of the cartilage. Conclusion. 3D chondral graft possesses high regenerative potencies realized by proliferative and synthetic activity inherent to embryonic cartilage. Nucleoplasty with chondral graft with its subsegment transformation into a definitive cartilage tissue improves structure-metabolism relationships and prevents neuro-vertebral conflict and intervertebral disc herniations.