Brain cortex lipid extracts from hypertensive rats with omega-3 fatty acids-supplemented diets analyzed by Langmuir monolayers and Brewster Angle Microscopy.

LUCRECIA LONGARZO; FRANCO DOLCETTI; ROMINA VAZQUEZ; M. CELESTE VILLA-ABRILLE; M. JOSÉ BELLINI; MARÍA L. FANANI; SABINA MATÉ

Virtual

Congreso; XLIX Reunión Anual Sociedad Argentina de Biofísica (SAB); 2021

Sociedad Argentina de Biofísica

Consumption of polyunsaturated fatty acids (PUFA´s) of the omega-3 series -eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)- produces beneficial effects in patients with neurodegenerative diseases. The incorporation of omega-3 in membranas may affect their biophysical and biochemical properties and, ultimately, celular pathophysiology.In this work, we evaluated the effect of early supplementing in diet with EPA and DHA over membrane composition and properties. We analyzed Langmuir monolayers composed of total lipids of rat brain cortex isolated from male wistar normotensive (W) and spontaneously hypertensive (SHR) rats. W and SHR animals were randomly separated into four groups: W control (W-C), SHR control (SHR-C), W treated (W-T) and SHR treated (SHRT). All groups were fed with standard rodent chow diet; the treated groups received omega-3 PUFAs orally every day (EPA 20:5 and DHA 22:6 doses 200 mg/kg body mass/day) during 16 weeks. On sacrifice day, cortex samples were isolated, and the total lipids were extracted.Lipid extracts were spread at the air/buffer interface and the phase behavior and rheological properties of the lipid monolayers were studied by recording the isothermal compression of the films and micrographs acquisition by Brewster Angle Microscopy (BAM) for the four conditions.All lipid extracts showed coexistence of liquid phases (liquid-expanded or Le and liquidordered or Lo) at low lateral pressures. W-T cortex lipids showed slightly lower miscibility surface pressures than W-C samples (~6.7 mN.m-1 vs. ~8.5 mN.m-1). Interestingly, in SHR-T samples the miscibility pressure was higher compared to SHR-C (~14.5 mN.m-1 vs. 7.8 mN.m-1). Accordingly, SHR-T samples showed higher differences in the mean gray values between the Le and Lo phases with a decrease in the gray levels compared to SHRC. These findings evidence an alteration in the lipid composition of cortex membranas related to both the pathological and treated condition.