FIG. 4.
Western blot analysis of the collagen type X/collagen type II expression ratio of pellets from the untreated positive control group receiving transforming growth factor-beta (TGF-β) but no PTHrP (C) compared with pellets that additionally received intermittent PTHrP(1–34) (P) during chondrogenesis. (A) Collagens were extracted from individual pellets on day 42 and collagen type II content was determined by ELISA. ELISA values were used to load approximately equal amounts of type II collagen per lane for each collagen extract of the control group and the pulsed group. This was done to standardize the samples on the same degree of chondrogenesis. By cutting the blot, collagen type II and collagen type X from the same pellet were stained. Representative results from nine sample pairs from four donors are shown. (B) Densitometric analysis of the western blots. (C) The densitometric volume of the collagen type X bands was related to the corresponding collagen type II band of the same sample, shown as the mean±SD. No significant differences were detected between the two groups, Wilcoxon test.