(LB04-03-26) Oral Intake of Linseed Oil That Suppresses Obesity-Related Skin Barrier Dysfunction Is Associated With Suppression of Hepatic Steatosis Progression

Objectives: We previously demonstrated that oral intake of linseed oil, rich in omega-3 fatty acids, suppresses skin barrier dysfunction in obese mice (Horie et al., 2024). At the same time, oral intake of linseed oil reduced liver weight in obese mice. Although obesity is a risk factor for hepatic steatosis, there is limited knowledge regarding the relationship among obesity, skin, and liver. This study aimed to examine whether oral intake of linseed oil, which suppresses skin barrier dysfunction in obese mice, suppresses progression to hepatic steatosis.

Methods: Obese model mice (TSOD) were divided into Control and Omega groups. The Control group received sterile distilled water, and the Omega group received linseed oil orally for 8 weeks. Body weight was measured weekly. After the intervention, dorsal hair was removed, and UVB (40 mJ/cm²) irradiation was applied. Transepidermal water loss (TEWL) was measured, and skin and liver were collected. Liver weight was measured, followed by histological analyses using HE and periodic acid–Schiff (PAS) staining. Fatty acid composition in both skin and liver was quantified. This study was approved by the Yokohama City University Animal Experiment Committee (F-A-23-051).

Results: Body weight did not differ significantly between the two groups. Compared with the Control group, the Omega group showed reduced liver weight and fewer hepatic lipid droplets by HE staining. PAS staining indicated a trend toward fewer PAS-positive hepatocytes in the Omega group. Fatty acid analysis showed increased alpha-linolenic acid (ALA) and decreased palmitic acid in skin and liver in the Omega group. ALA levels in skin and liver were positively correlated. For TEWL, ALA levels in skin and liver were negatively correlated, whereas palmitic acid levels were positively correlated.

Conclusions: These findings suggest that intake of lipids rich in omega-3 fatty acids not only suppresses obesity-induced skin barrier dysfunction but also suppresses progression to hepatic steatosis. Further studies are needed to clarify the detailed mechanisms underlying both the suppression of skin barrier dysfunction and the inhibition of progression to hepatic steatosis in obesity.

Funding Sources: This work was supported by a grant-in-aid for scientific research from MEXT (Ministry of Education Culture, Sports, Science and Technology; No. 25K20670).