GC-MS with Нeadspace Extraction for non-invasive Diagnostics of IBD dynamics in a Model of DSS-induced Colitis in Rats

Abstract

Abstract Background/Aims: Inflammatory bowel diseases are extremely common throughout the world. However, in most cases its asymptomatic at the initial stage. Therefore, it is important to develop non-invasive diagnostic methods that allow identification of the IBD risks in timely manner. It’s well known that gastrointestinal microbiota secreted volatile compounds (VOCs) and its composition may change in IBD. We propose a non-invasive method to identify the dynamics of IBD development in the acute and remission stage at the level of VOCs in stool of rats with chemically induced colitis measured by headspace GC/MS (HS GC/MS). Methods: VOCs profile was identified using a headspace GC/MS (HS GC/MS). GC/MS data were processed using MetaboAnalyst 5.0 ( http://www.metaboanalyst.ca ) and GraphPad Prism 8.0.1 software. The disease activity index (DAI) and histological method were used to assess intestinal inflammation. Results: The peak of intestine inflammation activity was reached on day 7, according to the disease activity index. Histological examination data showed changes in intestine due to different in inflammation stages. As the acute inflammation stage was reached, the metabolomic profile also underwent changes especially at short-fatty acids level. In remission stage, disease activity indexes decreased, and the histological picture also improved. But metabolome changes continued despite the withdrawal of the DSS examination. Conclusions: We observed changes in the metabolomic profile in the DSS model when a high inflammatory activity index was achieved. When DSS exposure was discontinued, the volatile profile was expected to return to initial levels. However, VOC levels continued to increase, indicating that reconstruction of microbiota composition continues even in remission. Thus, we hypothesize that with minor inflammatory damage to the intestinal mucosa, comparable to the initial stage of IBD development, changes in the composition of the microbiome are observed, which can be recorded by determining of VOCs.