Fig 5. SPARC effect on ECM proteins in differentiating myoblasts.

C2C12 cells were cultured in DM for 5 days with/without exogenous rSPARC (2 μg/ml) and/or anti-SPARC (10 μg/ml). The mediums were changed each 2 days. Proteins extraction was performed, and western blot analysis was done on RIPA soluble lysates to indicate proteins. The experiments were repeated three times (three different passages of C2C12 cells) and a representative western blot image was shown. Data were expressed as a ratio to the positive control (pooled samples). One-way ANOVA with repeated measurements was used to adjust the validations of the different passages and a contrast analysis was performed. P value was set at < 0.05 after the Bonfferoni adjustments. (a): collagen 1a1 levels were measured using the 30 μg proteins and the results showed that the induction of SPARC increased collagen 1a1 expression, however, an opposite effect of anti-SPARC was observed. (b) Five μg of the proteins were loaded to measure fibronectin levels. A decrease of fibronectin expression with rSPARC and an increase after anti-SPARC were observed. Abbreviations: PBS: phosphate buffered saline, rSPARC: recombinant SPARC protein, and anti-SPARC: anti-SPARC antibody. *Significant differences between experimental conditions.