Effect of lipopolysaccharide on toll like receptor 7 and toll like receptor 9 in AR42J cell lines

Abstract

Objective To investigate the roles of toll like receptor7 (TLR7) and toll like receptor 9 (TLR9) in the pathogenesis of acute pancreatitis.Methods AR42J cells were treated by lipopolysaccharide at different dosages (0,1,10,100 mg/L),and cell model of acute pancreatitis in vitro was established.AR42J cells without lipopolysaccharide treatment were as control.Cells and culture supernatant were collected after 24 hours cultivation.TLR7,TLR9 mRNA and protein expressions were detected by RT-PCR and Western Blot,and levels of TNF-α,IL-10 in culture supernatant were measured by ELISA.Results The TLR 7 mRNA expression levels in control group,1,10,100 mg/L lipopolysaccharide group were 0.12 ± 0.09,0.28 ± 0.06,0.49 ± 0.04,0.78 ± 0.04,and the TLR9 mRNA expression levels were 0.06 ± 0.02,0.32 ± 0.03,0.56 ± 0.14,0.84 ± 0.12; the TLR7 protein expression levels were 0.04 ± 0.01,0.26 ± 0.05,0.49 ±0.04,0.77 ±0.16,and the TLR9 protein expression levels were 0.10 ±0.14,0.62 ±0.23,1.21 ± 0.26,1.75 ± 0.13 ; the TNF-α levels in culture supernatant were (8.01 ± 5.32),(25.64 ± 8.71),(49.06 ± 10.23),(75.83 ± 6.65) ng/L,and the IL-10 levels were (155.54 ± 25.47),(105.16 ± 10.49),(69.36 ± 8.19),(14.07 ± 9.06)ng/L.The expression levels of TLR7 and TLR9's mRNA,protein in cell,as well as the levels of TNF-α in culture supernatant increased with the lipopolysaccharide concentration,while the levels of IL-10 in culture supernatant decreased with the lipopolysaccharide concentration,and the difference among these groups was statistically significant (P ＜ 0.01).Conclusions The expressions of TLR7 and TLR9 in AR42J cells treated by using lipolysaccharide are obviously up-regulated,and it suggests that TLR7 and TLR9 may be vital in the pathogenesis of acute pancreatitis. Key words: Pancreatitis ; Toll-like receptors ; Lipopolysaecharides ; Damage associated molecular patterns; AR42J cell