The limitations in efficacy and safety encountered with the current medical approaches for Inflammatory bowel diseases (IBD) continue to drive the search for better therapeutic agents. The aim of this study was to evaluate the effect of indigo in ulcerative colitis. Indigo is bis-indolic alkaloid and has antiulcerogenic, antioxidant, anti-inflammatory and analgesic activities.Methods:
Male mice Unib: SW (30–40 g) were divided into 4 groups: SAL (non-colitic control), IND (non-colitic test), SAL + DSS (colitic control) and IND + DSS (colitic test). Groups SAL + DSS and IND + DSS received solution of dextran sodium salt 3% (DSS) ad libitum instead of water for 7 days. During this period, daily, the animals were treated by gavage: vehicle 0.9% NaCl (10 mL/kg*) for groups SAL and SAL + DSS, and indigo (3 mg/kg*) for groups IND and IND + DSS. On the eighth day, animals were euthanized and the colon was removed for measurement of weight/length ratio of colon and quantification of cytokine levels (IL-1β, IL-6, IL-10, INF-g), by ELISA. Diarrhea, bloody stools and weight change were evaluated to define the disease activity index (DAI). Data are expressed as median (minimum-maximum) or mean ± SEM. Statistical analysis: Kruskal-Wallis test, followed by Duns or ANOVA, one way, followed by Tukey. The experiments were approved by the Ethics Commission in Animal Use—CEUA/Unicamp (CEUA numbers 2399–1 and 3743–1).Results:
The treatment with indigo did not alter DAI (SAL: 0 [0–1]a, IND: 0 [0–0],a SAL + DSS: 3.3 [2.7–4],b IND+ DSS: 2.7 [2.7–3.7]b), but prevented the increase in weight/length ratio of the colon SAL: 32 ± 4.3a; IND: 30 ± 2.5a; SAL + DSS 40 ± 6.4b; IND + DSS: 31 ± 4.1a g/cm*), and body weight loss. IL-6 and IL-1β levels were higher in the SAL + DSS group, which was prevented with the treatment with Indigo—IL-1β (SAL: 125.3 ± 13.1,a IND: 132.2 ± 8.5,a SAL + DSS: 280.0 ± 56.5,b IND + DSS: 181.6 ± 17.5a), IL-6 (SAL: 25.1 ± 3.4,a IND: 30.6 ± 7.6,a SAL + DSS: 158.3 ± 37.3,b IND + DSS: 45.9 ± 9.3a). The experimental groups did not show diferences in IL-10 and INF-g levels—IL-10 (SAL: 262.1 ± 22.3,a IND: 220.2 ± 14.0,a SAL + DSS: 339.9 ± 35.5,a IND + DSS: 297.4 ± 35.7a), INF-g (SAL: 213.8 ± 46.2,a IND: 164.2 ± 32.1,a SAL + DSS: 175.1 ± 32.6,a IND + DSS: 155.9 ± 16.1a).Conclusions:
Indigo showed no effect on DAI, however, the 7-days oral treatment with Indigo decreased weight/length ratio of the colon and body weight loss. Indigo also inhibited inflammatory cytokine release. These results suggests a potential role of indigo in colitis therapy.