fig3

Figure 3. The supernatants were collected from the co-culture wells for each condition. Then, ELISA tests were conducted to assess the secretion of type II collagen using species specific antibodies. The human collagen II results were normalized to the chondrocytes because they were presumed to show no expression, and the porcine collagen II results were normalized to the ADSCs, which were presumed to show no expression. The ELISAs were conducted using the supernatants from the collections at Weeks 3, 5, 7, and 9. For the human collagen II expression, there was essentially no expression throughout the experiment. However, for the porcine expression, there was a time-dependent increase for the 1:9 co-culture condition, with the nine-week reading showing the highest expression of any of the supernatants tested. The other conditions did not reveal any distinct pattern, indicating that the 1:5 co-culture was not different from culturing the chondrocytes alone. All quantitative data are expressed as the mean ± SD. A Student’s t-test was performed to assess the differences between the groups. A P-value < 0.05 was considered statistically significant. ADSCs: adipose derived stem cells; ELISA: enzyme-linked immunosorbent assay