Objective: To study the effects of Shenfu injection (SF) on the expression of lipopolysaccharide(LPS)-induced microRNA-146a (miR-146a) in rat alveolar macrophages (AMs), and to extrapolate its potential anti-inflammatory mechanisms.
Methods: In vitro cultured rat AMs (NR8383 cells) were randomly divided into control group, LPS stimulation group, and SF stimulation group. The LPS stimulation group was challenged with a final concentration of 1 mg/L LPS, and to the control group an equal volume of phosphate buffer solution (PBS) was added instead. For SF treated group, SF in different concentrations (1 ml/L or 10 ml/L) was used during incubation of AMs for half an hour, and then LPS was added (1 mg/L final concentration). After 6 hours, the cells and were collected. MiRNA-146a expression [reverse transcription-polymerase chain reaction (RT-PCR)] in cells and tumor necrosis factor-α (TNF-α ) content [enzyme-linked immunosorbent assay (ELISA)] in culture supernatant were determined for each group.
Results: Both the expression of miR-146a and TNF-α content in LPS stimulation group were significantly elevated compared with control group [miR-146a (expression folds): 5.92 + 1.57 vs. 1.04 +0.38; TNF-α (ng/L): 636.93 _ 30.21 vs. 20.46 + 2.81; both P<0.05]. Compared with LPS stimulation group, the expression of miR-146a was significantly upregulated in cells in both 1 ml/L and 10 ml/L SF stimulation groups, but TNF- α content was significantly reduced in the supernatant [miR-146a (expression folds): 7.02 + 0.91, 8.11 ± 1.07 vs. 5.92 -1.57; TNF-α (ng/L): 447.24 +21.29, 357.83 +19.73 vs. 636.93 +30.21, all P<0.05] in a dose-dependent manner (both P<0.05).
Conclusion: SF could up-regulate miR-146a expression in AMs in a dose-dependent manner, and it was speculated that miR-146a might be involved in the anti-inflammatory processes with SF treatment.