Dietary Intake of Green Nut Oil or DHA Ameliorates DHA Distribution in the Brain of a Mouse Model of Dementia Accompanied by Memory Recovery

Abstract

Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid, has significant health benefits. Previous studies reported decreased levels of DHA and DHA-containing phosphatidylcholines in the brain of animals suffering from Alzheimer’s disease, the most common type of dementia; furthermore, DHA supplementation has been found to improve brain DHA levels and memory efficiency in dementia. Oil extracted from the seeds of Plukenetia volubilis (green nut oil; GNO) is also expected to have DHA like effects as it contains approximately 50% α-linolenic acid, a precursor of DHA. Despite this, changes in the spatial distribution of DHA in the brain of animals with dementia following GNO or DHA supplementation remain unexplored. In this study, desorption electrospray ionization imaging mass spectrometry (DESI-IMS) was applied to observe the effects of GNO or DHA supplementation upon the distribution of DHA in the brain of male senescence-accelerated mouse-prone 8 (SAMP8) mice, a mouse model of dementia. DESI-IMS revealed that brain DHA distribution increased 1.85-fold and 3.67-fold in GNO-fed and DHA-fed SAMP8 mice, respectively, compared to corn oil-fed SAMP8 mice. Memory efficiency in SAMP8 mice was also improved by GNO or DHA supplementation. In summary, this study suggests the possibility of GNO or DHA supplementation for the prevention of dementia.

Green Nut Oil or DHA Supplementation Restored Decreased Distribution Levels of DHA Containing Phosphatidylcholines in the Brain of a Mouse Model of Dementia

“…Free DHA can incorporate into PCs and DHA-lysoPC of brain can be transformed into DHA-PCs by the action of lysoPC acyltransferase, and can improve the distribution levels of brain DHA-PCs in mice having dementia [35]. Therefore, our results of this study and previous reports suggest that GNO or DHA treatment could ameliorate the decreased distribution levels of brain DHA-PCs and improve memory function in dementia [10].…”

“…In our recent study, we have reported that fourteen weeks supplementation of GNO or DHA improves memory function and DHA accumulation in the brain of SAMP8 mice [10]. Therefore, in this study, we treated SAMP8 mice by CO, GNO, and DHA for 14 weeks and their brains were analyzed using DESI-MSI.…”

“…Recently, we have reported that fourteen weeks treatment with GNO or DHA improves brain DHA levels and memory function in SAMP8 mice [10]. Therefore, in this study, we analyzed the distribution levels of brain DHA-PCs in SAMP8 mice treated with GNO or DHA for 14 weeks ( Figure 4 and Figure S3).…”

Higher Accumulation of Docosahexaenoic Acid in the Vermilion of the Human Lip than in the Skin

“…Of the five FFAs detected in our study, DHA had a distinct distribution in the epithelium of the vermilion (Figure 4), which made a remarkable difference between the vermilion and the skin. DHA is an important omega-3 PUFA in the human body and is well known for its multiple beneficiary effects [20,24,25]. In the vermilion, DHA may play a role as an antioxidant and thus contribute to the anti-aging of the lip.…”

“…The assignments of the fatty acids were based on the m/z values and their mass tolerances, previous lipid studies using DESI-MSI [16,17,20,21], as well as The Human Metabolome Database (http://www.hmdb.ca/spectra/ms/search) [37]. We defined the skin, epithelium of vermilion, and its underlying tissue areas on the ion image with reference to the H&E staining of the same section.…”