Slow force response modulation by ω3 fatty acid supplementation in ovariectomized rats

ZAVALA MR; VELEZ RUEDA JO; DE GIUSTI VC; GARCÍA RB; PINILLA OA; PÉREZ NG; DÍAZ RG; LOFEUDO JM; VILLA-ABRILLE MC

La Plata

Congreso; Annual Meeting of the International Society for Heart Research (ISHR) Latin American Section; 2022

International Society for Heart Research (ISHR) Latin American Section

The stretch of cardiac muscle increases developed force in two phases: an initial rapid one,followed by a slowly developing one called ?slow force response? (SFR). Acute activation ofcardiac Na+/H+ exchanger (NHE1) plays a crucial role in the development of the adaptative SFR.However, sustained (chronic) exchanger hyperactivity may lead to cardiovascular disease. It iswell known that women after menopause increase cardiovascular risk. Interestingly, recentexperiments in cardiomyocytes from ovariectomized rats (a process that mimics menopause)demonstrated NHE1 overexpression and hyperactivity. On the other hand, several studies haveshown that consumption of omega-3 polyunsaturated fatty acids (ω3-FA) has cardioprotectiveeffects. In this context, the present study was aimed to characterize the SFR in OVX rats, and toevaluate the possible effects of a ω3-FA supplemented diet on this important mechanism.Two-month-old female rats were subjected to a bilateral ovariectomy (OVX group). A Sham (S)operated group (ovaries exposed but not dissected) was used as control. Thirty days aftersurgery, animals were aleatory separated to either follow receiving standard rat chow(untreated S and OVX) or begin an oral supplementation of ω3-FA (Sω3 and OVXω3, 200mg/kg/day, weekly adjusted for body weight) during the next 3 months. Systolic blood pressure(SBP) and body weight were determined (before surgery, during treatment and at sacrifice).The SFR development was measured in isolated left ventricle papillary muscles. Successfulovariectomy was confirmed by uterine atrophy, a procedure that also promoted an increase inbody weight without affecting SBP. Diet supplementation did not modify these parameters. Leftventricular mass index LVMI (mg/mm, used as hypertrophic parameter) showed a slight notsignificant tendency to be higher in OVX and OVXω3 rats. A similar SFR was observed in S, Sw3and OVX rats (112,9 ± 6,1%, n=3; 114,5 ± 1,9 %, n=2; 119,7 ± 1,7 %, n=4, respectively, ns). Incontrast, a significant decrease in SFR was observed in OVXω3 animals (103,3 ± 1,2 %, n= 4,p