We have used an unbiased, label-free SWATH proteomic approach to quantitate the response of skin fibroblast cells to the reductant DTT in the presence or absence of the growth factor PDGF. Of the 4487 proteins that were identified, only 47 proteins showed a statistically significant change of 2-fold or more with reducing stress. Our data demonstrates that reducing stress results in the loss of a small subset of reductant-sensitive proteins, including the fibrillar collagens (COL1A1/2 and COL3A1) and the myopathy-associated bundling collagen COL6A1/2/3.