Effects of hypertension and aging on fibronectin expression in aorta of Dahl salt-sensitive rats.

Effects of hypertension and aging on aortic fibronectin expression were investigated in male Dahl salt-sensitive (Dahl-S) and salt-resistant (Dahl-R) rats fed either a low- or high-salt diet from 5 to 37 wk of age. In comparison to low-salt controls, the steady-state mRNA levels for aortic fibronectin in salt-loaded Dahl-S rats were dramatically increased at 37 wk of age, corresponding to a severe stage of hypertension with high mortality, whereas at earlier ages representing early to established phases of hypertension, no significant changes were observed. Salt loading affected neither blood pressure nor aortic fibronectin expression in Dahl-R rats. Aging without coexisting hypertension did not cause significant changes in aortic fibronectin mRNA levels all through the study period in either strain of rats. These results suggest that aortic fibronectin may be strongly regulated by factors associated with severe hypertensive organ damages caused by long-standing hypertension in salt-loaded Dahl-S rats. Also suggested was that aortic fibronectin may not play a major role in the pathogenesis of early aortic changes occurring in response to hypertension or as a process of aging.