TREM1 Blockade Ameliorates Lipopolysaccharide-Induced Acute Intestinal Dysfunction through Inhibiting Intestinal Apoptosis and Inflammation Response

Objective The lipopolysaccharide- (LPS-) induced acute intestinal dysfunction model has been widely applied in recent years. Here, our aim was to investigate the effect of triggering receptor expressed on myeloid cells-1 (TREM1) inhibitor in LPS-induced acute intestinal dysfunction.Methods Male rats were randomly assigned into normal (saline injection), model (LPS and saline injection), and LP17 (LPS and LP17 (a synthetic TREM1 inhibitor) injection) groups. The levels of intestinal TREM1 expression were evaluated by immunohistochemistry and western blot. Intestinal permeability and apoptosis were separately assessed by the lactulose/mannitol (L/M) ratio and TUNEL assay. The levels of soluble TREM1 (sTREM1), TNF- α , IL-6, and IL-1 β were measured in the plasma and intestinal tissues by ELISA. The expression levels of NF- κ B, high-mobility group box 1 (HMGB1), and toll-like receptor 4 (TLR-4) were measured with RT-qPCR and western blot. After transfection with si-TREM1 in LPS-induced intestinal epithelium-6 (IEC-6) cells, p-p65 and p-I κ B α levels were detected by western blot.Results LP17-mediated TREM1 inhibition alleviated the intestine tissue damage in rats with LPS-induced acute intestinal dysfunction. LP17 attenuated the LPS-induced increase in sTREM1, TNF- α , IL-6, and IL-1 β levels in the plasma and intestinal tissues. Furthermore, intestine permeability and epithelial cell apoptosis were ameliorated by LP17. LP17 attenuated the LPS-induced increase in the expression of TREM1, HMGB1, TLR-4, and NF- κ B in the intestine tissues. In vitro, TREM1 knockdown inactivated the NF- κ B signaling in LPS-induced IEC-6 cells.Conclusion LP17 could ameliorate LPS-induced acute intestinal dysfunction, which was associated with inhibition of intestinal apoptosis and inflammation response.