Effect of aging and hypertension on beta-myosin heavy chain in heart of spontaneously hypertensive rats.
During aging rat myocardium undergoes structural changes characterized by a shift in the synthesis of myosin heavy chain (MHC) from V1 isoform, composed of two alpha-MHC, to V3 isoform, composed of two beta-MHC. In rat, besides ageing, cardiac hypertrophy as adaptive response to a superimposed pressure load (such as hypertension) is characterized by predominance of V3 myosin isoform. The aim of our study was to evaluate the expression of beta-MHC in right (RV) and left (LV) ventricles of spontaneously hypertensive rats (SHRs), a well defined animal model of hypertension, in relation to aging. We used very young (8-week old) and young (15-week old) SHRs and age-matched normotensive Harlan Sprague-Dawley control rats. By Western analysis, we found that beta-MHC is already present in both RV and LV of 8-week old SHRs, and is markedly predominant in RV and LV of 15-week old SHRs, when compared with age-matched control rats. Our study showed that the shift to V3 myosin isoform in SHRs is an early event, resembling accelerated senescence. We have also demonstrated that beta-MHC is actively synthesized also in young (15-week old) normal rats.
Compagno
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V
Istituto di Clinica Medica, Università degli Studi di Palermo, Palermo, Italy.
Di Liegro
I
I
Cestelli
A
A
Donatelli
M
M
D000375:Aging / Q000502:physiology*; D000818:Animals; D015153:Blotting, Western; D006352:Heart Ventricles / Q000378:metabolism*; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D018995:Myosin Heavy Chains / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR
D020033:Protein Isoforms; D018995:Myosin Heavy Chains