A decrease of lipid fluidity of the porcine intestinal brush-border membranes by treatment with malondialdehyde

Area of Science:

• Biochemistry
• Membrane Biology
• Physiology

Background:

• Porcine intestinal brush-border membranes are crucial for nutrient absorption.
• Lipid fluidity is a key determinant of membrane function.
• Malondialdehyde (MDA) is an indicator of lipid peroxidation and can alter membrane properties.

Purpose of the Study:

• To investigate the effect of malondialdehyde (MDA) on the lipid fluidity of porcine intestinal brush-border membranes.
• To elucidate the biophysical changes induced by MDA in membrane structure.

Main Methods:

• Utilized 1,6-diphenyl-1,3,5-hexatriene (DPH) as a fluorescence probe to measure membrane anisotropy.
• Assessed the impact of benzyl alcohol, a known fluidizer, on DPH-labeled membranes.
• Prepared liposomes from extracted lipids of MDA-treated membranes for further analysis.
• Employed SDS-polyacrylamide gel electrophoresis to examine membrane protein aggregation.

Main Results:

• MDA treatment increased DPH fluorescence anisotropy, indicating reduced lipid fluidity.
• The incorporation of DPH into membranes decreased following MDA treatment.
• The fluidizing effect of benzyl alcohol on membranes was suppressed by MDA.
• Liposomes from MDA-treated membranes showed increased DPH fluorescence anisotropy.
• SDS-PAGE indicated that protein aggregation was not responsible for the observed changes.

Conclusions:

• Malondialdehyde (MDA) treatment significantly decreases the lipid fluidity of porcine intestinal brush-border membranes.
• MDA alters the physical properties of the membrane, likely through direct interaction with lipids.
• These findings contribute to understanding the detrimental effects of oxidative stress on intestinal membrane integrity and function.