Role of Nrf2∕ARE signaling pathway in inhibition of LPS-induced inflammatory factor release from macrophages by hydrogen / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of nuclear factor erythroid 2?related factor 2 ( Nrf2)∕antioxidant response element( ARE) signaling pathway in inhibition of lipopolysaccharide ( LPS)?induced inflammatory factor release from macrophages by hydrogen. Methods RAW264. 7 macrophages of mice were cultured in 6?well plates (2×106 cells∕well) and were divided into 4 groups (n=24 each) using a random number table control group ( group C); LPS group; hydrogen?rich saline+LPS group ( group LPS+H2); Nrf2 small interference RNA (siRNA)+LPS+hydrogen?rich saline group (siRNA+LPS+H2 group) . LPS 1 μg∕ml was added in group LPS. In group LPS+H2 , LPS 1μg∕ml was added, and the cul?ture medium was then replaced with the culture medium containing 0. 6 mmol∕L hydrogen?rich saline. In group siRNA+LPS+H2 , after Nrf2?siRN was successfully transfected into the cells, the cells were continu?ously incubated for 24 h, and the culture medium was then replaced with the culture medium containing 0.6 mmol∕L hydrogen?rich saline after LPS 1 μg∕ml was added. At 24 h of incubation, the supernatant was sep?arated for determination of the lactic dehydrogenase (LDH) activity (using colorimetric method) and for detection of the concentrations of tumor necrosis factor?alpha ( TNF?α) , interleukin?1 beta ( IL?1β) , high mobility group box?1 (HMGB1) and IL?6 (by ELISA). The cells were collected for measurement of the proliferation of cells ( by methyl thiazolyl tetrazolium assay) and for determination of the expression of Nrf2 and heme oxygenase?1 ( HO?1) in cells ( by Western blot) . Results Compared with group C, the LDH activity and concentrations of TNF?α, IL?1β, IL?6 and HMGB1 in the supernatant were significantly in?creased, the proliferation of cells was significantly decreased, and the expression of HO?1 in cells was sig?nificantly up?regulated in LPS and siRNA+LPS+H2 groups, and the expression of Nrf2 in cells was signifi?cantly up?regulated in LPS and LPS+H2 groups (P<0.05). Compared with group LPS, the LDH activity and concentrations of TNF?α, IL?1β, IL?6 and HMGB1 in the supernatant were significantly decreased, the proliferation of cells was significantly increased, and the expression of Nrf2 and HO?1 in cells was sig?nificantly up?regulated in group LPS+H2 , and the expression of Nrf2 and HO?1 in cells was significantly down?regulated in group siRNA+LPS+H2 ( P<0.05) . Compared with group LPS+H2 , the LDH activity and concentrations of TNF?α, IL?1β, IL?6 and HMGB1 in the supernatant were significantly increased, the proliferation of cells was significantly decreased, and the expression of Nrf2 and HO?1 in cells was signifi?cantly down?regulated in group LPS+H2+siRNA ( P<0.05) . Conclusion The mechanism by which hydro?gen inhibits LPS?induced inflammatory factor release from macrophages is related to the activation of Nrf2∕ARE signaling pathway in mice.