ObjectiveTo investigate the impact of unfractionated heparin (UFH) on the expression of Syndecan-1 in the small intestine epithelium in mice with sepsis.MethodsTwenty-four 8-week-old female C57BL/6J mice were randomly divided into control group, UFH group, lipopolysaccharide (LPS) group, and LPS+UFH group, with 6 mice in each group. The LPS group was injected with 10 mg/kg LPS intraperitoneally; the LPS+UFH group was injected with 400 U/kg UFH via the tail vein 1 hour after injection of LPS; the UFH group was given 400 U/kg UFH; the control group was given an equal amount of saline. Four hours after modeling, serum and jejunal tissue were collected from each group, and the serum Syndecan-1 was measured by enzyme-linked immunosorbent assay (ELISA). HE staining was performed to assess the pathological changes of jejunal tissue. RT-qPCR, Western blot and immunofluorescence methods were used to detect the expression of Syndecan-1 in jejunum and its mRNA and protein expression, respectively.ResultsHE staining for the jejunal tissue in the control/UFH group was found normal; the LPS group showed moderate abnormalities, with loose arrrangement of intestinal villi and shortened length in the field of view, some epithelial cells in the mucosal layer were eroded and shed, inflammatory cell infiltration was observed in the tissue. The pathological score and injury degree of the LPS+UFH group showed improvement when compared to the LPS group. The serum Syndecan-1 in the LPS group was (79.58±1.69) ng/mL, which was significantly higher than that in the control and UFH groups [(38.85±1.66) ng/mL and (39.48±1.70) ng/mL, respectively, both P<0.01], while it was (55.08±2.16) ng/mL in the LPS+UFH group, significantly lower than that in LPS group (P<0.01). The mRNA expression of Syndecan-1 in the LPS group was significantly lower than those in the control/UFH group, reaching approximately 38% of the control group (P<0.01); the mRNA expression of Syndecan-1 in the LPS+UFH group was about 68% of the control group, which was much higher than that in the LPS group (P<0.01). Meanwhile, the protein expression of Syndecan-1 in the LPS group was significantly lower than that in the control and UFH groups, reaching approximately 40% (P<0.01), while the LPS+UFH group showed an increase to 77% (P<0.01). Immunofluorescence showed that LPS group had less positive expression of Syndecan-1 in jejunal epithelial cells than that in the control and UFH groups, about 26% (P<0.01). The positive expression of Syndecan-1 in LPS+UFH group was significantly higher than that in the LPS group (P< 0.01).ConclusionUFH can positively regulate the expression of Syndecan-1 in the intestinal epithelium of LPS-induced sepsis mice, reduce its degradation and shedding level, and improve the barrier function of the intestinal epithelium.