To explore the potential mechanism of rosmarinic acid in reducing sepsis related kidney injury.

In the animal experiment, BALB/c mice were randomly divided into animal control group, animal model group [10 mg·kg^-1 lipopolysaccharide (LPS) modeling], animal low-dose experimental group (modeling+10 mg·kg^-1 rosmarinic acid) and animal high-dose experimental group (modeling+20 mg·kg^-1 rosmarinic acid), with 10 mice in each group. In the cell experiment part, RAW264.7 cells were randomly divided into cell blank group, cell model group (1 μg·mL^-1 LPS), cell low-dose experimental group (modeling+20.00 μmol·mL^-1 rosmarinic acid) and cell high-dose experimental group (modeling+40.00 μmol·mL^-1 rosmarinic acid). Serum and renal tissue inflammatory related indicators were analyzed by enzyme linked immunosorbent assay (ELISA) kit and real-time fluorescent quantitative polymerase chain reaction (RT-qPCR). Renal tissue differentiation cluster 86 (CD86)⁺cells and F4/80⁺cells were co-located by immunohistochemistry.

In the animal experiment part, the serum creatinine (Scr) levels of animal control group, animal model group, low-dose experimental group and high-dose experimental group were (14.80±0.73), (59.73±6.79), (50.06±5.12) and (43.62±3.73) mmol·L^-1, respectively; the levels of inducible nitric oxide synthase (iNOS) were (1.26±0.11), (4.74±0.11), (3.86±0.23) and (2.48±0.28) U·L^-1, respectively; the levels of tumor necrosis factor-alpha (TNF-α) were (14.00±1.47), (85.90±6.66), (64.97±5.62) and (46.84±1.95) pg·mL^-1, respectively; the levels of interleukin (IL)-6 were (6.93±0.47), (50.05±3.84), (39.93±3.50) and (27.26±2.09) pg·mL^-1, respectively; the levels of IL-1 β were (22.17±2.27), (122.42±12.77), (91.54±6.84) and (61.23±6.31) pg·mL^-1, respectively; the CD86⁺/F4/80⁺ co-located cells were (100.00±4.85)%, (476.99±39.89)%, (322.15±24.15)% and (219.90±19.81)%, respectively. There were statistically significant differences in the above indexes between animal model and animal control group, between low-dose, high-dose experimental groups and animal model group, and between high-dose experimental group and low-dose experimental group (P<0.05, P<0.01, P<0.001). In the cell experiment, the relative expression levels of iNOS mRNA in the cell blank group, cell model group, cell low-dose experimental group and cell high-dose experimental group were 1.00±0.10, 3.26±0.31, 2.51±0.27 and 1.94±0.19, respectively; the relative expression levels of TNF - α mRNA were 1.00±0.14, 2.54±0.26, 2.07±0.22 and 1.77±0.18, respectively; the relative expression levels of IL-1β mRNA were 1.00±0.12, 2.24±0.30, 1.83±0.22 and 1.52±0.17, respectively; the relative expression levels of IL-6 mRNA were 1.00±0.08, 2.43±0.17, 1.85±0.21 and 1.54±0.16, respectively. There were statistically significant differences in the above indexes between cell model group and cell blank group, between low-dose and high-dose experimental groups and cell model group, and between high-dose experimental group and low-dose experimental group (P<0.01, P<0.001).

Rosmarinic acid plays a protective role in LPS-induced acute kidney injury by inhibit macrophage activation and inhibition of their transformation into M1-type macrophages.