Colon-specific scallop (Patinopecten yessoensis) hydrolysates/κ-carrageenan double cross-linking network gels loaded with curcumin alleviating DSS-induced colitis via modulation of inflammatory cytokines and gut microbiota

Abstract: Ulcerative colitis (UC) is a continual, relapsing inflammatory illness which mainly involves from rectum to submucosa. Curcumin (Cur) has been reported as a credible phytochemical component with effective treatment activity on UC whereas is prone to degradable during digestion process and exhibits short retention time in colon. In this case, scallop (Patinopecten yessoensis) male gonad hydrolysates/ κ-carrageenan (SK) double cross-linking network hydrogels were fabricated as Cur delivery vehicles, performing ideal UC mitigation behaviors. The resulting Cur-loaded hydrogels exhibited considerable gel mechanical strength and homogeneously honeycomb network. With the intervention of dextran sulfate sodium (DSS), the effect of various supplementation (SK, Cur and SK-Cur) on modulating colitis in mice were explored. As expected, Cur and SK-Cur supplementation effectively attenuated the clinical symptoms of DSS- stimulated UC mice, reflecting by less weight loss, decreased disease active index (DAI) indices, restored colon tissues with longer length and more intact intestinal epithelium, in which SK-Cur intervention manifested superior impact. Moreover, Cur-loaded administration could modulate oxidative stress and inflammatory expression, being symbolised by decreased MPO and iNOS levels, down regulated expression of TNF-α, IL-1β and IL-6 in couple with upregulated expression of IL-10, especially for SK-Cur, suppressing the epithelial to mesenchymal transition and thus alleviating inflammation. Furthermore, SK-Cur formulation regulated the ecological environment of the gut flora of colitis in mice, which was demonstrated by enriched Alpha-diversity and restored taxonomic composition with increasing community abundance of Bacteroides, Verrucomicrobia accompanying decreasing Firmicutes. Collectively, these results confirmed the development of the colon-specific drug delivery dietary SK-Cur in vivo, epitomizing the potential protective effect of SK on Cur as a nutritional supplement versus colitis and inflammatory-related diseases.