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Figure 7: Gene expression of disc stem cells and disc fibroblasts cultured with differentiation media for 21 days. (a) The gene expression of collagen types I, II, and III on disc stem cells (AFSCs and NPSCs) and disc fibroblasts (DFCs-AF and DFCs-NP). NPSCs expressed two times lower collagen type I ( when compared to AFSCs) and higher collagen type III than the other three types of cells, AFSCs, DFCs-AF, and DFCs-NP ( when compared to AFSCs; when compared to NPSCs). However, higher collagen type II expression was found in NPSCs, DFCs-AF, and DFCs-NP compared to that in AFSCs ( when compared to AFSCs). (b) Multidifferentiation potential of AFSCs cultured with various differentiation media for 21 days. The gene expression in differentiated AFSCs was found to be 4 times higher on PPARγ (adipocyte marker gene), 2 times higher on Runx-2 (osteocyte marker gene), and 20 times higher on SOX-9 (chondrocyte marker gene) compared to those in AFSCs. AFSCs: the AFSCs were cultured with normal growth medium (DMEM-10% FBS) for 21 days; differentiated AFSCs: the AFSCs were cultured with either adipogenesis or osteogenesis or chondrogenesis media for 21 days ( when compared to AFSCs cultured with normal growth medium). (c) Multidifferentiation potential of NPSCs cultured with various differentiation media. The gene expression in differentiated NPSCs was found to be 3 times higher on PPARγ (adipocyte marker gene), 2 times higher on Runx-2 (osteocyte marker gene), and 29 times higher on SOX-9 (chondrocyte marker gene) compared to those in NPSCs. NPSCs: the NPSCs were cultured with normal growth medium (DMEM-10% FBS) for 21 days; differentiated NPSCs: the NPSCs were cultured with either adipogenesis or osteogenesis or chondrogenesis media for 21 days ( when compared to NPSCs cultured with normal growth medium).