Objective To explore the possible mechanism and optimal treatment phase of glycine for inhibition lipopolysaccharide (LPS)
induced Kupffer cells (KCs) activation. Methods The KCs were isolated from 40 BALB/c mice and divided into four groups: the endotoxin group, the prevention group, the early treatment group and the later treatment group (n=10). The endotoxin group was treated with 10 mg/L LPS, and in the other three groups, glycine (1 mmol/L) was given 24 h before, or at 0 h or 4 h respectively after LPS stimulation. At 0 h, 1 h, 2 h, 6 h and 12 h after LPS stimulation, the mRNA levels and protein
expression of
interleukin-1 receptor associated kinase-4 (IRAK-4) were determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot respectively, and nuclear factor-kappaB (NF-κB) activities as well as tumor necrosis factor alpha (TNF-α) levels were also detected by enzyme-linked immunosorbent assay (ELISA). Results The climax values of IRAK-4, NF-κB and TNF-α were significantly higher in the endotoxin group and the later treatment group than that in the other two groups (t=3.17, 4.33, 2.47, 126.73, P<0.01). Conclusion The results indicated that prophylactic or simultaneous treatment with glycine could effectively inhibit LPS-induced KCs activation by inhibiting IRAK-4 expression.