OBJECTIVETo investigate the effect of compound qingqin liquid (CQL) on Toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4) in rats with urate nephropathy, and to explore its renal protection mechanism.

METHODSTotally 55 SD rats were randomly divided into 5 groups, i.e., the normal control group (n =5), the model group (n =10), the positive drug group (n=10), and the high-, medium-, low-dose CQL groups (n=10) respectively. The urate nephropathy model was induced by intragastrically administering adenine and feeding yeast. Distilled water was intragastrically administered at the daily dose of 10 mL/kg to rats in the normal control group and the model group. Allopurinol was intragastrically administered at the daily dose of 9.33 mg/kg to rats in the positive control group. CQL was intragastrically administered at the daily dose of 3.77, 1.89, 0.94 g/kg to rats in the high-, medium-, and low-dose CQL groups. Rats of each group were executed in batches at the 4th and 6th week respectively. Their kidney tissues were taken out to determine the mRNA transcription level of TLR2 and TLR4 by reverse transcription-polymerase chain reaction (RT-PCR). The protein expression level of TLR2 and TLR4 were determined by Western blot. The protein expression level of TLR4 was also detected by immunohistochemical assay.

RESULTSAt week 4 and 6, the protein expression of TLR2 and TLR4 as well as the mRNA transcription of TLR4 increased in the model group, when compared with the control group (P < 0.05, P < 0.01). Compared with the model group, there was no statistical difference in the transcription level of TLR2 mRNA or TLR4 mRNA among the 3 CQL groups (P > 0.05) at week 4 and 6. Additionally, at week 6, the protein expression of TLR4 and TLR2 could be reduced by CQL (P < 0.05, P < 0.01).

CONCLUSIONCQL might protect kidney tissue against inflammatory injury by inhibiting the protein expression levels of TLR2 and TLR4.