Molecular and immune profiling of colorectal polyps using FTIR microspectroscopy.

Colorectal polyps (CRP) are abnormal protuberances of tissue that grow into the lumen from the typically flat colonic mucosa; according to their morphology, they are classified as sessile or pedunculated, and considering their behaviour, they can be classified as benign or malignant. Some CRP can be precursors to colorectal cancer. Therefore, this research aimed to analyze, using micro-FTIR, the biomolecular components and immune responses in mice with CRP. Fifteen mice of the C57BL/6 strain were randomly divided into two groups: healthy and CRP groups. The murine model of CRP was induced with azoxymethane and dextran sulfate sodium for 50 days. The weight and evaluation of the mouse Grimace scale were evaluated, and morphometric, histopathological, and micro-FTIR analyses of the colon were conducted. Finally, the molecular and immunological profiles were analyzed using micro-FTIR spectra. The CRP group showed weight loss and a significantly higher Grimace scale score than the healthy group. Furthermore, the colon length and weight decreased in the CRP group. Histopathologically, at 40X, a significant number of lymphatic nodules and inflammatory infiltrate were observed. At 100X, dysplasia of the Lieberkühn crypts with a star-shaped appearance was evidenced in the CRP group. In micro-FTIR spectra of the CRP group, the fingerprint region showed lower absorbance, and humoral immunity and cellular responses showed lower expression. The results are consistent with dysplasia features, and spectroscopy suggests that the CRP exhibits immune characteristics of a cold tumor.