A. E. Louiselle1, S. Niemiec1, M. Azeltine1, L. Zhang1, M. Stager2, M. Krebs2, C. Zgheib1, K. Liechty1 1University Of Colorado Denver,Laboratory For Fetal And Regenerative Biology, Department Of Surgery,Aurora, CO, USA 2Colorado School of Mines,Chemical And Biological Engineering,Golden, CO, USA
Introduction: Increased inflammation and oxidative stress are key features in the pathogenesis of Inflammatory Bowel Disease (IBD). We have previously shown that local delivery of a CNP-miR146a-Chitosan gel enema into the Dextran Sodium Sulfate (DSS)-murine model of colitis/IBD results in decreased TNF-alpha expression within the injured colon as well as clinical improvements including decreased blood in stool and more formed stools. CNP-miR146a is a novel conjugate that combines free-radical scavenging cerium oxide nanoparticle (CNP) and anti-inflammatory microRNA, miR146a, that synergistically targets both oxidative stress and inflammation, as is seen in IBD. Here we propose that local administration of CNP-miR146a in a Chitosan gel enema would also result in decreased gross pathologic and histopathologic findings of the mouse colon.
Methods: C57BL/6J age-matched mice (n=15) were divided equally into three groups. The control group received regular water and a PBS enema on experiment day three. The IBD colitis mice received 3% DSS water to induce colitis and a PBS enema or a CNP-miR146a enema on experiment day three. Mice were sacrificed on experiment day six and their colon length was measured and then placed in 10% formalin solution, fixed and then stained with H&E. We used a modified published scoring model to score each of the H&E slides for all groups. The division of points fell broadly into three categories: Inflammatory cell infiltrate (0-7 points), epithelial changes, (0-25 points) and mucosal architecture alterations (0-25 points) for a maximum total score of 57.
Results: The average colon length for the control group was 6.75 cm, which was shortened in the diseased group at 4.9 cm, and improved for the treated group at 5.6 cm. The average histology score of the control group was 1.25, of the diseased group was 20.8, and of the treated group was 13.4 (p<0.05 for all groups). We observed improvement in crypt and villous architecture, decreased inflammatory cell infiltrate, and less goblet cell loss and variability in the treatment group as compared to the diseased group.
Conclusion: These results demonstrate that there is improved colon length along with lessened histological disease severity in the colon tissue of DSS-colitis mice when treated with a single therapeutic CNP-miR146a enema as compared to a PBS enema. These finding support the clinical improvements previously observed and highlight the potential of CNP-miR146a as a promising treatment for IBD.
