Comparison of the Production of Extracellular Matrix in Nucleus Pulposus of Intervertebral Disc in Alginate and Chitosan-Gelatin Scaffolds

Low back pain is an important disorder linked with degenerative changes in the intervertebral disc (IVD). Degradation of IVD is caused by decreased number of cells, reduced production and degradation of extracellular matrix of IVD tissue especially in nucleus pulposus (NP). Natural and synthetic scaffolds are used for regeneration of IVD in tissue engineering. Aggrecan is an important proteoglycan in NP tissue of IVD. This study aimed to levels of aggrecan secreted by human NP cells of IVD in alginate and chitosan-gelatin scaffolds. Collagenase enzymatic hydrolysis was used to extract NP cells from NP tissue of patients with IVD hernia in Alzahra Hospital (Isfahan, Iran). Chitosan gel was mixed with gelatin gel and freeze dried to make the scaffold. An alginate scaffold was also prepared. Cellular suspension containing the extracted NP cells was transferred to each scaffold and cultured for 14 days. The levels of secreted aggrecan were investigated by enzyme-linked immunosorbent assay. A light microscope was used to assert the morphology of NP cells. Secretion of aggrecan had significant increases during the third to the 14th day. The increments were more considerable in alginate scaffolds There were significant differences in secreted aggrecan between alginate and chitosan scaffolds on the seventh and 14th days. However, no such a significant difference was observed on the third day. Compared to the chitosan-gelatin scaffold, the alginate scaffold provided better conditions for aggrecan secretion in NP cells in vitro. The use of thus scaffold is suggested to culture NP cell in vivo.