ABSTRACT
OBJECTIVE: To investigate the protective effect and possible mechanism of Rhizoma Coptis(RC) on lipopolysaccharide(LPS)-induced inflammatory injury in rat hepatocytes(BRL). METHODS: LPS-induced BRL cells injury model was established in vitro, then the damaged cells were given different interventions and treatment with 0.175, 0.1 mg• mL-1 RC aqueous extract as the test drug, and dexamethasone(Dex) as positive control drug. The optimal test doses of LPS and RC aqueous extract were selected and determined by cell counting kit-8(CCK-8), the cellular apoptosis rate was determined by flow cytometry, TLR4/NF-κB and TLR4/IRF3 signaling pathways and the mRNA level of related inflammatory mediators(TNF-α, IL-1β, IL-6) were detected by RT-PCR, the NF-κB p65 protein expression was analysed by Western blot and immunofluorescence techniques. RESULTS: ①Compared with normal control group, 0.1 mg•mL-1 LPS affected on BRL cells for 24 h, the cell survival rate was decreased significantly(P<0.01), the apoptotic rate increased significantly(P<0.01), the mRNA level of TLR4, NF-κB, IRF3, TNF-α, IL-1β, IL-6 were significantly increased(P<0.01), and the NF-κB p65 protein expression was increased. ②Compared with the model group, 0.1 and 0.175 mg•mL-1 RC affected on LPS-induced BRL cells for 24 h, the survival rate of BRL cells was increased significantly(P<0.05), the apoptotic rate decreased significantly(P<0.01), the mRNA level of TLR4, NF-κB, IRF3, TNF-α, IL-1β, IL-6 and the NF-κB p65 protein expression were decreased significantly(P<0.01). CONCLUSION: Rhizoma Coptis has obviously protective effect on LPS-induced inflammatory injury in rat hepatocytes(BRL), the mechanism of which may be related with inhibiting apoptosis, reducing the release of inflammatory factors such as TNF-α, IL-1β and IL-6, blocking NF-κB p65 protein nuclear translocation, interfering the R4/NF-κB and TLR4/IRF3 signaling pathway.