Selective Visualization of Administrated Arachidonic and Docosahexaenoic Acids in Brain Using Combination of Simple Stable Isotope-Labeling Technique and Imaging Mass Spectrometry

Abstract

We developed a new method for monitoring the distribution of administrated fatty acids in the body by combination of a stable isotope-labeling technique and imaging mass spectrometry (IMS). The developed stable isotope-labeling technique is very simple and able to adapt to all the fatty acid species. In this study, we synthesized stable isotope-labeled arachidonic acid (AA) and docosahexaenoic acid (DHA), and they were simultaneously administrated to mice to examine their migrations and distributions in the brain. The administrated AA and DHA have two more molecular weights compared to the originals and apparently were distinguished from the originally accumulated AA and DHA in the brain using IMS. As a result, we reveal that the administered AA and DHA first accumulated in the hippocampus and cerebellar cortex in the brain. This technique does not use radio isotopes and would appear to elucidate the role of all kinds of fatty acid species in the body.

Dietary triacylglycerol hydroperoxide is not absorbed, yet it induces the formation of other triacylglycerol hydroperoxides in the gastrointestinal tract

“…Preparation of FA 18:1[D2] was conducted according to previous studies [ 16 , 17 ]. FA 18:1; 1OMe (1 g) was refluxed at 105 °C for 30 min in CH 3 OD (10 mL) solution containing 3% (w/v) sodium methoxide.…”

Incorporation of Dietary Arachidonic and Docosatetraenoic Acid into Mouse Brain

“…It is difficult to obtain the necessary amount of stable isotope-labeled PUFAs for animal experiments because of their cost and limited number of suppliers. Thus, we previously reported a deuterium labeling method of PUFA . All deuterium-labeled PUFA ethyl esters were analyzed by GC–MS.…”

“…Thus, we previously reported a deuterium labeling method of PUFA. 23 All deuterium-labeled PUFA ethyl esters were analyzed by GC−MS. Mass spectra of (+2)DTA ethyl ester (m/z 363 [M + H] + ) and (+2)AA ethyl ester (m/z 335 [M + H] + ) are illustrated in Figure 2.…”

“…The deuterium-labeled AA ((+2)­AA) ethyl ester and DTA ((+2)­DTA) ethyl ester (Figure ) were synthesized according to our previous work . Briefly, methyl esters of AA or DTA were refluxed in a mixture of methanol-OD (CH 3 OD) and sodium methoxide.…”

“…The deuterium-labeled AA ((+2)AA) ethyl ester and DTA ((+2)DTA) ethyl ester (Figure 1) were synthesized according to our previous work. 23 Briefly, methyl esters of AA or DTA were refluxed in a mixture of methanol-OD (CH 3 OD) and sodium methoxide. After being cooled to ambient temperature, a mixture of CH 3 OD and boron trifluoride ethyl ether complex was added to the reaction mixture and refluxed.…”