Fig. 1

UC/PL-MSC-CM exhibits protective effects on the clinical course of chronic DSS-induced colitis. A Experimental design of repeated "cycles" of DSS exposure, as described in the "Methods" section. Mice were randomized into four groups: (1) control group (water-treated mouse group, n = 15); (2) DSS group (DSS and vehicle-treated mouse group, n = 15); (3) UC/PL-MSC-CM-Exp. 1 group (DSS and UC/PL-MSC-CM-treated mouse group according to Exp. 1 schedule, n = 10); and (4) UC/PL-MSC-CM-Exp. 2. (DSS and UC/PL-MSC-CM-treated mouse group according to Exp. 2 schedule, n = 15). Three DSS administration cycles induced chronic DSS colitis and intestinal fibrosis. One DSS cycle comprised of 7 d oral administration of DSS (1.75%, 2%, and 2.5% DSS), followed by 14 d of water drinking. In Exp. 1, the UC/PL-MSC-CM was injected intraperitoneally ten times during the late phase of the DSS cycles, starting from day 50. In Exp. 2, the UC/PL-MSC-CM was administered ten times during the early phase of the DSS cycles, starting from day 29. B Relative weight curve. C Relative weight at day 64. D Macroscopic appearance of the colons from the mice. E Colon length, colon weight, and colon weight/colon length of mice. Data are expressed as means ± SEM (n = 10–15 in each group). ^###P < .001 versus the control group; ^*P < .05, ^**P < .01 and ^***P < .001 versus the DSS group (ANOVA w/ Tukey)