Effects of lipopolysaccharides in different concentrations on the proliferation and interleukin-6, interleukin-1β and tumor necrosis factor-α secretion of intestinal epithelial cell of rats in vitro / 中华实用儿科临床杂志

ABSTRACT

Objective To investigate the effects of lipopolysaccharides (LPS) in different concentrations on the proliferation and interleukin(IL)-6,IL-1 β and tumor necrosis factor-α(TNF-o) secretion of intestinal epithelial cells (IEC-6) of rats in vitro.Methods IEC-6 of rats were divided into normal group (0 mg/L,group A),0.1 mg/L group (group B),0.5 mg/L group (group C),1.0 mg/L group (group D),5.0 mg/L group (group E) and 10.0 mg/L group(group F).Different groups cells were exposed to LPS with different concentrations for 3 h,5 h and 7 h.Thiazolyl blue(MTT) was performed to investigate the proliferation of IEC-6.The concentrations of IL-6,IL-1 β and TNF-α in culture supernatant were detected by enzyme linked immunosorbent assay(ELISA).Results The proliferation rate of IEC-6 was gradually lower while the concentration of LPS increased.After co-culture with LPS 3h and 5 h,the proliferation rates of group B,group C,group D,group E and group F had no significant difference with those of group A (all P ＞ 0.05);after co-culture with LPS 7 h,the proliferation rates of group B,group C,and group D had no significant difference with those of group A (all P ＞ 0.05);the proliferation rates of group E and group F had significant difference with those of group A(t =4.216,P =0.014;t =14.991,P =0.000).The proliferation rates of group E and group F were lower after co-culture with LPS 5 h than 7 h,and there were significant differences (t =2.576,P =0.033;t =2.975,P =0.018);but there was no significant differences between group E and group A after co-culture with LPS 5 h (P ＞ 0.05).Group B,group C,group D,group E and group F all had a significant higher level of IL-6 than group A after co-culture with LPS 3 h,5 h and 7 h(all P ＜0.01).In addition,group E had the highest level of IL-6 at all time points.And the peak level of IL-6 rose after co-culture with LPS 5 h.The TNF-α level and IL-1 β level of group B,group C,group D,group E and group F all had no significant differences than that of group A after co-culture with LPS 3 h,5 h and 7 h (all P ＞ 0.05).Conclusions In a certain concentration,incubation time range,the proliferation rates of IEC-6 cells were gradually lower while the concentration of LPS increased.Co-cultured IEC-6 cells with LPS(0-10.0 mg/L) can stimulate them secrete to IL-6.The highest level of IL-6 was of group E after 5 h co-culture.LPS had no effects on TNF-α and IL-1 β level of IEC-6 cells cultural supernatant.So 5.0 mg/L concentration of LPS stimulating IEC-6 cells for 5 h can be chosen to build the IEC-6 inflammatory models.