Evaluation of different doses of acetic acid on the induction of acute ulcerative colitis and cytokine profile in BALB/c mice; An experimental study

IBD is a multifactorial disease that is classified as Crohn's disease and ulcerative colitis. in this study, we aimed to assess the effects of different volume of 4% acetic acid to induction of acute ulcerative colitis and immunological responses in BALB/c mice.

In this experimental study, mice were divided into four groups (five mice in each group). Then, control group was injected intrarectally with normal saline, in the case groups different volume of 4% acetic acid (60, 80 and 100 μl) were injected intrarectally. Clinical manifestations of colitis in mice including: weight loss, bleeding and diarrhea were evaluated daily. The animal groups were sacrificed on day 3 after injection and were examined microscopically and macroscopically. The supernatant of spleens cells was harvested and IFN-γ and IL-10 concentrations were measured by sandwich ELISA. The results of the study were analyzed and reported using Graphpad Prism software version 5.

In microscopic and macroscopic examinations, significant lymphocyte infiltration was observed in the injected groups with doses of 60, 80 and 100 μl of acetic acid compared to the control group. However, no significant difference was observed macroscopically and microscopically between the acetic acid groups at doses of 60 and 80 μl. The use of 100 doses of acetic acid also induced colitis with acute symptoms and no mortality in mice. Also, evaluation of cytokines after induction of ulcerative colitis showed a significant increase in IFNγ levels and a decrease in IL-10 in the acetic acid group with a dose of 100, compared with the control group and other groups.

It seems that the use of 100 μl of 4% acetic acid with the proposed protocol can induce acute experimental colitis in female BALB/c mice as an optimal dose.