Periodic high extracellular glucose enhances production of collagens III and IV by mesangial cells

We examined the effects of periodic changes in extracellular glucose concentration on matrix production and proliferation using three groups of cultured rat mesangial cells (MCs): 1) MCs in medium with continuous 5 mM glucose (CL), 2) MCs in medium alternating daily between 5 and 25 mM glucose (PH), and 3) MCs in medium with continuous 25 mM glucose (CH). MCs cultured in PH for 10 days produced 329 and 110% more type III collagen protein than MCs cultured in CL and CH, respectively. MCs cultured in PH induced 31 and 14% more type IV collagen than MCs cultured in CL and CH, respectively. Extracellular glucose concentration had no effect on the amount of type I collagen produced. MCs cultured in PH or CH for 5 days also expressed increased levels of type I, III, and IV collagen mRNA compared with MCs cultured in CL. MCs cultured in PH for 8-10 days also produced significantly more DNA than MCs in CL or CH. These data suggest that the temporal pattern of exposure to high extracellular glucose plays a role in...