Effect of TREM-l expression on the apoptosis of intestinal macrophages of rats

Objective To investigate the effect of triggering receptor expression in myeloid cells-1 (TREM-1) on intestinal macrophage apoptosis in rat. Methods In vitro, the achieved rat intestinal macrophages were divided into 3 groups: control group, LPS (Lipopolysaccharides) group and LPS +LP17 group (n =6 holes of culture plate in each). The concentrations of LPS and LP17 were 1 mg/L and 0.1 mg/L, respectively. The intestinal macrophage apoptosis was measured by using TUNEL kit and flow cytometry after culture for 6 h. All data were statistically analyzed using SPSS 18.0 software. Results The shape and growth of rat intestinal macrophages were quite favorable after culture. The membrane marker of intestinal macrophages, CD14 was clearly observed under immunofluorescence. After macrophage was treated with specific procedure, the cell apoptosis found in LPS group (44.33 ± 7.74) % was significantly higher than that in control group (19.17 ± 6.01) % (P =0.000) measured by TUNEL; the cell apoptosis in LPS +LP17 group (28.33 ± 6.53)% apparently reduced compared with LPS group (44.33 ±7.74) % (P = 0.004) ; there was no significant difference in cell apoptosis between control group (19.17 ± 6.01) % and LPS +LP17 group (28.33 ± 6.53) % (P =0.050). By flow cytometry, the apoptotic cells in LPS group (16.47 ± 1.66) % was significantly increased compared with control group (7.70 ± 1.52) % (P =0.000) ; apoptotic cells in LPS +LP17 group (11.47 ± 3.12) % was significantly reduced in comparison with LPS group (16.47 ± 1.66) % (P =0.018). There was no significant difference in apoptotic cells between control group (7.70 ± 1.52)% and LPS +LP17 group (11.47 ± 3.12) % (P =0.061). Conclusion LP17 can inhibit TREM-1 expression in intestinal macrophages and reduce intestinal macrophage apoptosis. Key words: Intestinal macrophages; Triggering receptor expressed on myeloid cells-1; Apoptosis; Lipopolysaccharides; LP17; Intestinal mucosa barrier; one-step TUNEL; Flow cytometry