OBJECTIVETo investigate the effect of Compound Qingqin Liquid (CQL) on the expression level of angiotensin II (Ang II) and COX-2 mRNA transcription and protein expression in the renal tissue of rats with uric acid nephropathy.

METHODSSD rats were randomly divided into the blank control group, the model group, the positive drug group, the high, moderate, and low dose CQL group according to number randomization principle. The model was established by gastrogavage of adenine, accompanied with yeast feeding. Distilled water was given by gastrogavage to rats in the blank control group and the model group. Allopurinol at the daily dose of 9.33 mg/kg was given by gastrogavage to rats of the positive control group. CQL at the daily dose of 3.77 g/kg, 1.89 g/kg, and 0.09 g/kg was respectively given by gastrogavage to rats in the high, moderate, and low dose CQL groups. All treatment lasted for 6 weeks. Rats were randomly divided at week 4 (3 in the blank control group, and 6 in the rest groups), and the rest rats were killed at week 6. The renal tissue was extracted. The expression level of Ang II and COX-2 mRNA transcription were detected by RT-PCR. The expression level of Ang II was detected by ELISA. The expression level of COX-2 protein was detected by Western blot and immunohistochemical assay.

RESULTSCompared with the blank control group, except the mRNA expression of Ang II at week 4, the mRNA and protein expression of Ang II and COX-2 obviously increased at week 4 and 6 in the model group (P < 0.01, P < 0.05). The COX-2 protein expression at week 4 was obviously lower in the high and moderate dose CQL groups than in the model group and the low dose CQL group (P < 0.05); the average integral of optical density value was obviously lower in the positive control group than in the model group. Except the mRNA expression of Ang II in the high dose CQL group at week 6, the mRNA and protein expression of Ang II obviously decreased in the positive control group and each dose CQL group (P < 0.01, P < 0.05). Of them, the effects were better in the high and moderate dose CQL groups than in the positive control group and the low dose CQL group (P < 0.05, P < 0.01). Besides, the mRNA expression of COX-2, the average integral of optical density value were obviously lower in the positive control group and each dose CQL group than in the model group (P < 0.05). The protein expression of COX-2 was obviously lower in the high and moderate dose CQL groups than in the model group (P < 0.05). Of them, the mRNA expression of COX-2 was better in the moderate dose CQL group than in the positive control group (P < 0.05); the protein expression of COX-2 was better in the high dose CQL group than in the low dose CQL group (P < 0.05).

CONCLUSIONCQL was capable of lowering the expression level of Ang II, COX-2 mRNA transcription and protein expression, thus suppressing the inflammatory pathological injury of the renal tissue.