Baicalin attenuates lipopolysaccharide-induced renal tubular epithelial cell injury by inhibiting the TXNIP/NLRP3 signalling pathway via increasing miR-223-3p expression

Baicalin has been used in China to treat inflammation-related diseases, such as inflammation-induced acute kidney injury (AKI). However, the specific mechanism of baicalin remains unclear. To observe the protective effects of baicalin on lipopolysaccharide (LPS)-induced inflammatory injury of renal tubular epithelial cells (HK-2 cells) and to explore its protective mechanism. LPS (1 mg/L) was used to induce an HK-2 cell inflammatory injury model in vitro. The cells were divided into seven groups: the normal control group, LPS-induced group, LPS plus 5 μmol/L baicalin treatment group, LPS plus 15 μmol/L baicalin treatment group, LPS plus 25 μmol/L baicalin treatment group, LPS plus 50 μmol/L baicalin treatment group, and LPS plus 75 μmol/L baicalin treatment group. 3-(4,5-dimethyl-2-thiazolyl)-2,5- diphenyl-2-H-tetrazolium bromide (MTT) assay was employed for detecting the relative survival rate of HK-2 cells. Enzyme-linked immunosorbent assay was used for detecting the levels of inflammatory factors, including interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α). Moreover, the expression of inducible nitric oxide synthase (iNOS); cyclooxygenase-2 (COX-2); nuclear factor kB65 (NF-κB65); phosphorylated NF-κB inhibitory protein-α (p-IκB-α); NF-κB inhibitory protein (IκB); human thioredoxin interacting protein (TXNIP); and human NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) were determined by Western blot analysis. The expression levels of NLRP3 and TXNIP mRNA and miR-223-3p were determined by RT-PCR. Results found that the relative survival rate of HK-2 cells treated with different baicalin concentrations was significantly increased (P