TNF and type 2 diabetes mellitus: In normal wound healing TNF-α levels increase approximately 12 to 24 h after wounding, returning to basal levels following the proliferative phase24, so we exposed cultured ND-DF and T2DM-DF to supra-physiological doses of TNF-α for 3 days, before removing and culturing in the absence of TNF-α for a further 11 days (14 days in total) to mimic this transiency.