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

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

Virtual

Congreso; XLIX Reunión Anual de la Sociedad Argentina de Biofísica SAB 2021.; 2021

Consumption of polyunsaturated fatty acids (PUFA´s) of the omega-3 series -eicosapentaenoic acid(EPA) and docosahexaenoic acid (DHA)- produces beneficial effects in patients withneurodegenerative diseases. The incorporation of omega-3 in membranes may affect theirbiophysical and biochemical properties and, ultimately, cellular pathophysiology.In this work, we evaluated the effect of early supplementing in diet with EPA and DHA overmembrane composition and properties. We analyzed Langmuir monolayers composed of totallipids of rat brain cortex isolated from male wistar normotensive (W) and spontaneouslyhypertensive (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 (SHR-T). All groups were fed withstandard rodent chow diet; the treated groups received omega-3 PUFAs orally every day (EPA 20:5and DHA 22:6 doses 200 mg/kg body mass/day) during 16 weeks. On sacrifice day, cortex sampleswere isolated, and the total lipids were extracted.Lipid extracts were spread at the air/buffer interface and the phase behavior and rheologicalproperties of the lipid monolayers were studied by recording the isothermal compression of thefilms 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 liquid-ordered orLo) at low lateral pressures. W-T cortex lipids showed slightly slower miscibility surface pressuresthan W-C samples (~6.7 mN.m-1 vs. ~8.5 mN.m-1). Interestingly, in SHR-T samples the miscibilitypressure was higher compared to SHR-C (~14.5 mN.m-1 vs. 7.8 mN.m-1). Accordingly, SHR-Tsamples showed higher differences in the mean gray values between the Le and Lo phases with adecrease in the gray levels compared to SHR-C. These findings evidence an alteration in the lipidcomposition of cortex membranes related to both the pathological and treated condition