Abstract: Objective To investigate the protective effect and mechanism of total flavones of psidium guajava leaves (TFPGL) on kidneys of diabetic rats. Methods Twenty-four male SD rats were divided into control group, diabetic group and TFPGL treatment group by random number table method. The diabetic model was induced by single intraperitoneal (IP) injection of streptozotocin (55 mg/kg). After 12 weeks, samples of blood, urine and kidney tissues were collected to detect the changes of blood sugar (BS), blood urea nitrogen (BUN), urine protein/creatinine ratio (ACR) and serum creatinine (SCr). The pathological changes of kidney were detected by HE staining. The expressions of Nrf2 and HO-1 in kidney were detected by immunofluorescence, immunohistochemical staining and Western blot assay. Results Compared with the control group, BS, BUN, ACR and SCr were increased significantly in diabetic group, the expression of Nrf2 was increased, the expression of HO-1 was decreased (all P＜0.01). Compared with the diabetic group, the levels of BS, BUN, ACR and SCr were decreased significantly, while Nrf2 and HO-1 increased significantly in diabetic group after treatment with TFPGL (all P＜0.05). Conclusion TFPGL has a certain therapeutic effect on diabetic nephropathy in rats. Its mechanism may be related to the decreased blood sugar and activated Nrf2/HO-1 signaling pathway.

Key words: diabetic nephropathies, NF-E2-related factor 1, heme oxygenase-1, oxidative stress, Total Flavones of Psidium Guajava Leaves