Gene expression profile and aortic vessel distensibility in voluntarily exercised spontaneously hypertensive rats: potential role of heat shock proteins.
Ulrika Hägg¹, Maria E. Johansson1, Julia Grönros¹, Andrew S. Naylor¹, Ingibjörg H. Jonsdottir^1,3, Göran Bergström^1,2, Per-Arne Svensson⁴ and Li-ming Gan1,^2
1 Department of Physiology, Institute of Physiology and Pharmacology, Göteborg University;² Department of Clinical Physiology, Cardiovascular Institute, Sahlgrenska University Hospital, Göteborg, Sweden
Physiol. Genomics , 22: 319-326, May 24, 2005

• > Physical exercise is considered to be beneficial for cardiovascular health. Nevertheless, the underlying specific molecular mechanisms still remain unexplored. In this study, we aimed to investigate the effects of voluntary exercise on vascular mechanical properties and gene regulation patterns in spontaneously hypertensive rats. By using ultrasound biomicroscopy (Vevo 660, VisualSonics) in an ex vivo perfusion chamber, we studied the distensibility of the thoracic aorta. Furthermore, exercise-induced gene regulation was studied in aortae, using microarray analysis and validated with real-time PCR. We found that distensibility was significantly improved in aortas from exercising compared with control rats (P < 0.0001). Exercising rats demonstrated a striking pattern of coordinated downregulation of genes belonging to the heat shock protein family. In conclusion, voluntary exercise leads to improved vessel wall distensibility and reduced gene expression of heat shock protein 60 and 70, which may indicate decreased oxidative stress in the aortic vascular wall.
  
  Note: High-resolution UBM (Vevo 660, VisualSonics) has been used successfully to image mouse cardiovascular morphology and function in vivo. Using a custom-designed small-vessel perfusion chamber, morphology of the isolated aortae could be clearly visualized using UBM. To extend the previous in vivo observation of increased aortic compliance, the isolated vessels were studied in a physiological saline solution instead of calcium-free solution, used when only the passive vascular mechanical properties are studied. Apparently, this ex vivo approach facilitates extended physiological studies of the vessels also at the paraphysiological pressure levels. Furthermore, thanks to the accurate measurement of the vessel lumen diameter, potential confounding effects of different vessel calibers can be taken into account.