The effect of different treatments of lymph after intestinal ischemia-reperfusion in rats on macrophages in vitro

BACKGROUND: To observe the effects of different treatments of lymph after intestinal I/R in rats on macrophages in vitro. METHODS: Forty-eight healthy SPF SD rats weighing 300 ± 20 g, were randomly divided into two groups: group A, and group B. The rats in group A were drained of lymph fluid for 180 min; the rats in group B were subjected to 60 min ischemia by clamping the SMA, followed by 120 min reperfusion and 180 min of lymph drainage. The lymph fluid collected was divided into 4 sub-groups: 1. no treatment (A1, Ly, and B1, I/R Ly); 2. protein degradation (A2, Ly PD, and B2 I/R PD); 3. endotoxin removal (A3, Ly ER, and B3, I/R ER); 4. protein degradation plus endotoxin removal (A4, Ly PD+ER, and B4, I/R PD+ER), then used to stimulate a monocyte-macrophage cell line. RESULTS: Compared with group A1, the levels of the inflammatory cytokines, chemokines, HMGB1 concentration, protein and mRNA expression of TLR4, HMGB1 and NF-κBp65 were significantly increased in group B1. There was a significant reduction in proinflammatory cytokines and of the expression of TLR4, NF-κBp65, and chemokines in groups A2, B2, A4, and B4. However, there were no significant decrease of these factors in groups A3 and B3. CONCLUSIONS: The lymph fluid drained after intestinal I/R can cause inflammation in vivo and in vitro. Deproteinization of lymph fluid with proteinase K significantly reduced the concentration of proinflammatory cytokines, chemokines, TLR4 and NF-κBp65 in cell culture supernatant, exerting a protective effect on inflammatory reaction caused by the intestinal I/R. Passage of lymph fluid through an endotoxin removal column did not reduce the levels of active proinflammatory factors produced by macrophages in vitro.