Soybean oil increases SERCA2a expression and left ventricular contractility in rats without change in arterial blood pressure.
Our aim was to evaluate the effects of soybean oil treatment for 15 days on arterial and ventricular pressure, myocardial mechanics and proteins involved in calcium handling.



Wistar rats were divided in two groups receiving 100 microL of soybean oil (SB) or saline (CT) i.m. for 15 days. Ventricular performance was analyzed in male 12-weeks old Wistar rats by measuring left ventricle diastolic and systolic pressure in isolated perfused hearts according to the Langendorff technique. Protein expression was measured by Western blot analysis.



Systolic and diastolic arterial pressures did not differ between CT and SB rats. However, heart rate was reduced in the SB group. In the perfused hearts, left ventricular isovolumetric systolic pressure was higher in the SB hearts. The inotropic response to extracellular Ca2+ and isoproterenol was higher in the soybean-treated animals than in the control group. Myosin ATPase and Na(+)-K(+)ATPase activities, the expression of sarcoplasmic reticulum calcium pump (SERCA2a) and sodium calcium exchanger (NCX) were increased in the SB group. Although the phosfolamban (PLB) expression did not change, its phosphorylation at Ser16 was reduced while the SERCA2a/PLB ratio was increased.



In summary, soybean treatment for 15 days in rats increases the left ventricular performance without affecting arterial blood pressure. These changes might be associated with an increase in the myosin ATPase activity and SERCA2a expression.
Hertel Ribeiro
Eduardo
E
Department of Physiological Sciences, Federal University of Espirito Santo, Vitoria, Brazil. faustino43@oi.com.br
Fernandes
Aurélia Araújo
AA
Meira
Eduardo Frizzera
EF
Batista
Priscila Rossi
PR
Siman
Fabiana Dayse Magalhães
FD
Vassallo
Dalton Valentim
DV
Padilha
Alessandra Simão
AS
Stefanon
Ivanita
I
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006321:Heart; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000032:analysis*; D013024:Soybean Oil / Q000494:pharmacology*; D013599:Systole / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects; D016277:Ventricular Function, Left / Q000187:drug effects*
D013024:Soybean Oil; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases