〔Abstract〕 Objective To investigate the effect of platelet particles on the extent of intestinal inflammation and intestinal mucosal permeability in mice with dextran sodium sulfate induced colitis. Methods The experiment was divided into four groups: normal control group(n=10, drinking sterile distilled water + intraperitoneal injection of 0.9% sodium chloride solution), PMPs group(n=10, drinking sterile distilled water + intraperitoneal injection of PMPs), DSS model group(n=10, drinking DSS solution + intraperitoneal injection of 0.9% sodium chloride solution), and experimental group(n=15, drinking DSS solution + intraperitoneal injection of PMPs).Peripheral blood-derived PMPs suspension was collected from inflammatory bowel disease(IBD) patients. A colitis model was constructed in mice by allowing them to freely drink a 5% DSS solution for 1 week, followed by continuous intraperitoneal injection of PMPs for 7 days. Disease activity index(DAI) scores was recorded daily and the severity of intestinal inflammation with histopathological scores(HI) was assessed by HE staining of colon samples at the end of the experiment. Myeloperoxidase(MPO), neutrophil elastase(NE), citrullinated histone H3(citH3), and free DNA levels were measured in colon homogenate, observe intestinal mucosal structure by transmission electron microscopy, and intestinal permeability was tested using fluorescein isothiocyanate-dextran(FITC-D). Results Compared with the normal control group, the colonic mucosa of mice in the PMPs group showed edema, severe destruction of epithelial structure, extensive aggregation of inflammatory cells, and increased overall HI score(P<0.01); the levels of inflammatory factors such as IL-1β and TNF-α in colonic tissue homogenates of mice in the PMPs group increased(P<0.05), and the expression of NETs increased(P<0.05); the plasma FITC-D level of mice in the PMPs group significantly increased(P<0.05), and the permeability of intestinal mucosa increased.Compared with the DSS group, the experimental group mice had higher plasma FITC-D levels(P<0.05) and more electron microscopic colonic epithelial damage.Conclusion PMPs induces NETs formation in mice, promotes colonic inflammation in mice, increases intestinal mucosal permeability and aggravates intestinal inflammation in mice with DSS colitis.