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

ZAVALA, MR; VELEZ RUEDA OJ; DE GIUSTI, VC; GARCIA, RB; PINILLA, A; PÉREZ NG,; DÍAZ, RG; LOFEUDO, JM; VILLA ABRILLE, MC

La Plata

Congreso; 2022 Annual Meeting of 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). It is known that activation of the cardiac Na+/H+ exchanger (NHE1) plays a crucial role in the development of the SFR, and also that hyperactivity of this exchanger triggers several cardiovascular pathologies. On the other hand, it is also known that women after menopause increase cardiovascular risk. Interestingly, we have recently demonstrated that cardiomyocytes from ovariectomized (OVX) rats (a process that mimics menopause) are characterized by a significant overexpression and hyperactivity of the NHE1, while several studies have shown that consumption of omega-3 polyunsaturated fatty acids (ω3-FA) has cardioprotective effects. In this context, this study was aimed to characterize the SFR in OVX rats, as well as the possible effects of a ω3-FA supplemented diet on this adaptative 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. Successful ovariectomy was confirmed by uterine atrophy. Thirty days after surgery, the animals were separated in the following groups: untreated S and OVX, and treated Sω3 and OVXω3 which received ω3-FA supplementation orally during 3 months (200 mg/kg/day, weekly adjusted for body weight). Systolic blood pressure (SBP) and body weight were determined before surgery, during treatment and before sacrifice. The SFR development was measured in isolated left ventricle papillary muscles. Ovariectomy produced uterine atrophy and increased body weight without affecting SBP. Diet supplementation did not modify these parameters. Left ventricular mass index LVMI (mg/mm, used as hypertrophic parameter) showed a slight not significant tendence to be higher in OVX and OVX3 rats. A similar SFR was observed in S, Sw3 and OVX rats (112,9  6,1%, n=3; 114,5  1,9 %, n=2; 119,7  1,7 %, n=4, respectively, ns), while a significant decrease in this parameter was observed in OVXω3 (103,3  1,2 %, n= 4, p