Aortic crosstransplantation between young and old rats: effect upon the heat shock protein 70 stress response.

In previous studies we demonstrated that restraint, or immobilization stress, resulted in the induction of HSP70 mRNA in the vasculature of rats. This response was confined to the vascular smooth muscle, was associated with alpha 1-adrenergic receptor stimulation, and was attenuated with age. In the present study, we examined the influence of transplanting aged vessels into young animals and young vessels into aged animals to determine if this age-related diminution was due to changes intrinsic to the aorta or the result of alterations in the environment in which the aorta resides. We demonstrate that restraint-induced HSP70 expression in transplanted vessels is influenced to a greater degree by the age of the recipient than by the age of the transplanted vessel. Transplantation of aged vessels into young animals leads to preservation of the response, whereas transplantation of young vessels into aged animals leads to attenuation. These findings indicate that the environment in which the vessel resides is a major factor in determining this molecular response to stress.