Fig. 7.
SPARC exerts anti-adipogenic effect on omental adipocytes and 3T3-L1 cells. a Oil Red O (ORO) staining of differentiating SP+/+ and SP–/– pre-adipocytes (×10 magnification). b SP–/– adipocytes exhibit increased size and number of fat droplets day 10 (D10) post-differentiation as shown by ORO (×20 magnification) and electron microscopy (×6800). c Plots indicate mean ± SEM of the number (upper) and size (lower) of lipid droplets quantified in EM images (10 cells/experimental condition). P values are determined by Student's t-test. d Western blots showing the kinetics of expression of adipogenic transcription factors during differentiation of SP+/+ and SP–/– pre-adipocytes. e The expression of SPARC protein during differentiation of SP+/+ adipocytes. f Effect of SPARC (5 µg/ml in PBS–0.4% BSA) on the expression of the adipogenic transcription factors during differentiation of SP+/+ adipocytes. Tubulin was used as loading control. g Confluent 3T3-L1 pre-adipocytes (D0) were differentiated either in the presence or absence of 5 μg/ml rSPARC up to day 10. The cells were harvested at days 0, 3, 7, and 10. Intracellular lipids were stained with ORO. h Bars (right) represent means ± SEM of the quantification of ORO-stained cells solubilized with 100% isopropanol for 5min and measuring the absorbance A492 nm. *p < 0.0001, two-way ANOVA with Sidak post-hoc test. h Images of Bodipy fluorescent staining of intracellular lipids in differentiating 3T3-L1 pre-adipocytes in the presence or absence of 5 μg/ml rSPARC. i Western blots showing the expression of SPARC and the adipogenic differentiation markers in differentiating 3T3-L1 cells in the presence or absence of SPARC