(PTFS11-05-24) Dietary Curcumin Supplementation Improves Gut Integrity and Inflammation Markers in Obese Aged Mice

Objectives: The current study evaluated the effects of curcumin (cur), the principal curcuminoid of turmeric, on markers of gut integrity and inflammation in the context of aging associated with obesity.

Methods: Eighteen-month-old C57/BL6 male mice were randomly assigned into four dietary treatment groups (n=6-9/group): control (normal chow diet, NCD), control with 0.4% (w/w) curcumin (NCD + cur), high-fat high-sugar diet (HFHSD, 49% fat kcal, 22% glucose kcal), and HFHSD + cur. After 8 weeks on their respective diets, mice were sacrificed and the colon and ileum were harvested and examined for gene expression of inflammation markers (TNF-α, IL-1β, IL-10, and IL-6) and tight junction proteins (TJP1 and OCLN). Additionally, immunoblotting analysis was conducted to assess the protein levels of the tight junction proteins (OCLN and CLNDN1) in the ileum. Data were analyzed using 2-way ANOVA followed by post-hoc tests when p < 0.05.

Results: In the ileum, HFHSD increased the expression of pro-inflammatory genes (IL-1ß and TNF-α). However, mice in the HFHSD + cur group had significantly lower (p < 0.05) gene expression of IL-1b (^ΔΔCt, 0.8 ± 0.35) compared to the HFHSD group (^ΔΔCt, 3.0 ± 0.93), indicating a positive impact of curcumin on the gut. Similarly, a significant increase (p < 0.05) in gene expression of TNF-α and IL-6 in the colon was noted in the HFHSD groups but no curcumin effect. Interestingly, curcumin intake decreased colonic IL-1β levels (p < 0.05) in both control and HFHSD groups. Curcumin significantly increased gene expression of OCLN (p < 0.05) in both the ileum and colon but has a modest effect on TJP1. However, the protein expression of OCLN in the ileum was significantly lower (p < 0.05) in the HFHSD groups, and no curcumin effect. Both HFHSD and curcumin have no significant effect on the anti-inflammatory marker IL-10 and CLDN1 protein levels in the ileum.

Conclusions: Our findings suggest that curcumin can improve gut health in obese aged mice by reducing inflammation and enhancing gut integrity markers, particularly OCLN.

Funding Sources: NIH the Intramural Research Program (IRP), Ottogi Ham Taiho Foundation, and Jim and Lyn Williams Professorship