Abstract: Objective To observe the expression changes of angiotensin-converting enzyme 2(ACE2) in kidney tissue of rats with diabetic nephropathy, and explore the renal protection mechanism of lycopene. Methods The rats were divided into 5 groups: nomal control group, diabetic nephropathy (DM) model group, and Lycopene treated groups with high-dose (20 mg·kg^-1·d^-1), middle-dose (10 mg·kg^-1·d^-1), and low-dose (5 mg·kg^-1·d^-1) respectively. After 8 weeks, the blood and urine index was measured. The expression level of ACE2 protein in kidney tissue was detected respectively by immunohistochemistry and western blotting. Results The concentrations of blood glucose, serum insulin, creatinine, urea nitrogen, AngII and urine protein in lycopene and diabetes groups were all significantly higher than those of normal control group (P<0.05); After treated by lycopene, serum creatinine, urea nitrogen, AngII and urine protein were greatly improved (P<0.05). The expression of ACE2 protein in diabetes group was greatly decreased than that of normal control group (P<0.01), while ACE2 protein levels in the high- and middle-dose groups treated with lycopene were obviously up-regulated (P<0.05), especially in high-dose lycopene group (P<0.01). Conclusion Lycopene can decrease urine protein, improve the renal function, and up-regulate the expression of ACE2 protein in diabetic nephropathy.

Key words: Lycopene, Diabetic nephropathy, ACE2