I am doing research in (multiple sclerosis) and I'm working with macrophages (MA). I added several lipids to my MA cultures for 48h, wanting them to take up the lipids, and them afterwards stain them with ORO to see whether the MA had taken up the lipids.
I used 5 different lipids, one sort of lipid/culture.
The lipids used are Sulfatide (SU) (neutral?), Gangliosides (GA) (neutral?), Phosphatidylserine (PS) (charged?), Phosphatidylethanolamine (PE) (charged?) and Phosphatidylinositides (PI) (charged?).
I am thus working with an Oil Red O staining (figure upper part), and know that it stains NEUTRAL lipids. However, in my cultures with the phospholipids (PS, PE, PI), I also see MA that stain red, even though these lipids are known to carry a charge.
In any case, I like the result, but I need an explanation for it..
How is this possible? Maybe when the phospholipids are taken up by the MA they become neutralized?
Or does someone have a better explanation for this?
I stained other MA cultures with SBB (figure lower part) and here it stains what it should stain, only the phospholipids.