Figure 3.

Primary cells isolated from SPARC-null mice proliferate faster than wild-type counterparts. A and B represent mesangial cells (wild-type [□] and SPARC-null [●]) plated at equal densities (low, 5 × 10² cells/ml [A], and high, 1 × 10³cells/ml [B]) in triplicate, in a 24-well plate. The mesangial cells were counted 2 h after plating to determine the number of attached cells at the onset of the experiment. No differences in initial plating efficiency were detected between the SPARC-null and the wild-type cells in either the fibroblast or the mesangial cell cultures. (C and D) Wild-type (□) and SPARC-null fibroblasts (●) were plated at equal concentrations in triplicate, in a 24-well plate. C shows an initial plating density of 1 × 10³ cells/ml (low), whereas D shows a higher initial plating density of 1 × 10⁴ cells/ml. All values have error bars that represent the SEM.