Fig. 5.

Fibronectin is differentially degraded by solar simulated and UVA radiation. (a) The 220 kDa fibronectin monomer (Mon: identified by reference to a 217 kDa Mw. Marker), was clearly evident by SDS-PAGE (i) regardless of UVR exposure and there was no evidence of UVR induced fragmentation. However the normalised optical intensity of higher Mw. fibronectin species (aggregates: Ag), was increased at higher UVR doses (SSR 7.7 and 15.4 J/cm² and UVA 10 and 20 J/cm²) and evident in densitometric line profiles extracted from non-UV exposed and SSR and UVA exposed suspensions (ii). (b) Although both UVR sources induced fibronectin aggregation in a dose-dependent manner (SSR: r² = 0.99, UVA: r² = 0.94), UVB-containing SSR was seven times as effective in inducing aggregation compared with UVA alone.