Voluntary physical exercise and coronary flow velocity reserve: a transthoracic colour Doppler echocardiography study in spontaneously hypertensive rats.
In the present study, we have developed and demonstrated a coronary artery imaging protocol in rats using transthoracic high-frequency CDE (colour Doppler echocardiography) to investigate the potential direct effects of exercise on CFVR (coronary flow velocity reserve). SHR (spontaneously hypertensive rats) performed voluntary exercise for 6 weeks. Rats were then submitted to ultrasonographic examination and CFVR measurements. The LAD (left anterior descending coronary artery) was visualized using transthoracic CDE in a modified parasternal long-axis view. Doppler measurement was made in mid-LAD during baseline and adenosine-induced hyperaemic condition. Gene and protein expression in cardiac tissue were studied using real-time PCR and immunohistochemistry. Adenosine infusion significantly (P<0.001, as determined by ANOVA) decreased HR, without affecting blood pressure in anaesthetized SHR. A significantly greater adenosine dose-dependent response was seen in exercised rats compared with controls (P=0.02, as determined by ANOVA). The baseline flow velocity in mid-LAD was 0.33+/-0.06 and 0.41+/-0.14 m/s in the exercised and control animals respectively (P value was not significant). The maximum adenosine-induced response was reached at a dose of 140 microg.kg-1 of body weight.min-1, and CFVR averaged at 2.6+/-0.53 and 1.5+/-0.24 in exercised and control animals respectively (P<0.01). Gene expression of CuZnSOD was up-regulated by 21% in exercised animals compared with controls (1.1+/-0.16 compared with 0.89+/-0.09; P<0.01), whereas eNOS expression was unchanged. In conclusion, CFVR in rats can be non-invasively assessed using CDE with high feasibility. Physical exercise is associated with improved CFVR and antioxidative capacity in SHR.
Hägg
Ulrika
U
Department of Physiology, Institute of Physiology and Pharmacology, Göteborg University, Göteborg, Sweden.
Grönros
Julia
J
Wikström
Johannes
J
Jonsdottir
Ingibjörg H
IH
Bergström
Göran
G
Gan
Li-ming
LM
D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004195:Disease Models, Animal; D018618:Echocardiography, Doppler, Color; D005240:Feasibility Studies; D015971:Gene Expression Regulation, Enzymologic; D006339:Heart Rate; D006973:Hypertension / Q000000981:diagnostic imaging / Q000201:enzymology / Q000503:physiopathology*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012420:Running; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
D013482:Superoxide Dismutase