Optimization of dextran sulfate sodium-induced colitis and associated mortality in BALB/c mice

Dextran sulfate sodium (DSS)-induced colitis in BALB/c mice has revealed underlying mechanisms of colitis pathology. This study aimed to optimize the DSS dosage to improve reproducibility while ensuring high survival rates. Mice were treated with 2 and 3% DSS solutions in drinking water daily for 7 days (days 1-7), followed by water (8-14 days). Disease activity index (DAI) and survival percentage were monitored over 14 consecutive days. On the last day, intestinal permeability was assessed by Evans blue assay, and colon length was measured. After sacrifice, colon samples were collected to evaluate mucopolysaccharide content and processed for histological analysis with hematoxylin-eosin (HE), periodic acid-Schiff (PAS), and Alcian blue (AB) staining. The results were analyzed to identify significant differences between groups, considering a P-value ≤0.05 as significant. Compared to the control group, DAI, inflammatory cell infiltrate, and intestinal permeability were higher, while colon length, body weight, and mucopolysaccharide content were lower in both DSS groups. Compared to the 2% DSS group, the 3% DSS group showed higher relative density of AB+ cells, higher DAI on days 7, 9, and 14, greater inflammatory infiltrate, and lower PAS+ cells. In addition, survival was lower in the 3% DSS group (57%) compared to the 2% DSS group (80%). According to these findings, 2% DSS provided higher survival and symptomatic colitis, making it the best choice for inducing DSS colitis in mice.