Objective To study the protective effect and mechanism of Lycopus lucidus Turcz ethanol extract on STZ induced diabetic mice kidney.Methods The diabetic mice model were induced by single intraperitoneal injection of 0.12 mg/g STZ.After 60h, the mice successful modeling were divided into model control group,Lycopus lucidus Turcz ethanol extract high-dose group [5.0g/(kg? d)]and low-dose group [1.25/(kg? d)], 10 mice in each group.Another 10 normal mice were used as normal control group.The high-and low-dose group were intragastric administrated corresponding dose Lycopus lucidus Turcz ethanol extract, normal control group and model control group were given the same volume of sterile distilled water.After 5 weeks, the mice kidney structure was observed by periodic acid-Schiff ( PAS ) , advanced glycosylation end products ( AGEs ) and transforming growth factorβ1 (TGF-β1) in kidney tissue were detected by ELISA.The monocyte chemotactic protein-1 (MCP-1) mRNA expression were detected by RT-PCR and MCP-1 protein expression by Western blot in mice kidney.Results PAS staining results showed, compared with model control group,renal structural changes in high-dose group was significantly increased.ELISA results showed AGEs and TGF-β1 content in kidney tissue of model control group were higher than normal control group (P<0.01), the above indexes of high-dose group were lower than model control group (P<0.05) .RT-PCR results showed MCP-1 mRNA expression of model control group was higher than normal control group (P<0.01), MCP-1 mRNA expression of low-and high-dose group model group were lower than model control group (P<0.01), and MCP-1 mRNA expression of high-dose group was lower than low-dose group (P<0.05).Western blot results showed MCP-1 protein expression of model group was higher than normal control group (P<0.01), but there were no significant differences of MCP-1 protein expression between low-or high-dose group model group and model control group. Conclusion Lycopus lucidus Turcz ethanol extract can protect the STZ-induced diabetic mice kidney, and it might be the reason of inhibiting the expression of AGEs-MCP-1-TGF-β1.