Hesperetin ameliorates diabetic nephropathy in rats by activating Nrf2/ARE/glyoxalase 1 pathway.

Diabetic nephropathy (DN) is one of the most common diabetic complications, and alpha-carbonyl aldehydes and their detoxicating enzyme glyoxalase 1 (Glo-1) play vital roles in pathogenesis of diabetic complications. The aim of this study was to evaluate the renoprotective effects of hesperetin against DN in rats, and to investigate mechanisms from the aspect of Nrf2/ARE/Glo-1 pathway. Streptozotocin-induced diabetic rats were treated orally with hesperetin (50 and 150 mg/kg), or nuclear factor erythroid-derived-2-like 2 (Nrf2) inducer tert-butylhydroquinone (tBHQ, 25 mg/kg) for 10 weeks. Then proteinuria, creatinine, urea nitrogen, and uric acid were assayed for renal functions, fibronectin and collagen IV levels by immunohistochemistry, as well as periodic acid-Schiff staining and electron microscope observation, were used to assess renal morphology. Glo-1 activity, protein, and mRNA levels and the classic Nrf2/ARE pathway were investigated. Moreover, advanced glycation endproducts (AGEs) and its receptor RAGE, interleukin-1ß and tumor necrosis factor-α levels were also examined in the kidney. Hesperetin markedly ameliorated the renal functions and structural changes of diabetic rats, accompanied by up-regulation of Glo-1 as well as inhibition of AGEs/RAGE axis and inflammation. Meanwhile, hesperetin caused significant increases in Nrf2 and p-Nrf2 levels, as well as up-regulation of γ-glutamylcysteine synthetase, a well-known target gene of Nrf2/ARE signaling. Our results demonstrated that hesperetin could slow down the pathological process of DN, and Glo-1 enhancement contributed to the beneficial effects, which was obtained by the activation of Nrf2/ARE pathway.

Protective effects of sarsasapogenin against early stage of diabetic nephropathy in rats.

Rhizome of Anemarrhena asphodeloides Bunge (AA, family Liliaceae) has been widely used in China for thousands of years to treat febrile diseases and diabetes. Steroidal saponins from AA show good antidiabetes effects and ameliorate diabetic complications. This study was designed to investigate the effects of sarsasapogenin (Sar), a major sapogenin from AA, on diabetic nephropathy (DN) in rats, and to explore the possible mechanisms. Diabetic rats were divided into 3 groups treated orally with Sar (0, 20, or 60 mg/kg) and carboxymethylcellulose sodium, whereas normal rats for Sar (0 or 60 mg/kg) and carboxymethylcellulose sodium. We found that chronic treatment with Sar for 9 weeks significantly ameliorated renal dysfunction of diabetic rats, as evidenced by decreases in albuminuria, kidney weight index, serum uric acid, and morphologic changes such as extracellular matrix expansion and accumulation (fibronectin and collagen IV levels, etc.). Meanwhile, Sar treatment resulted in decreases in interleukin-18, NLRP3, and activated caspase 1 levels as well as advanced glycation endproducts (AGEs) and their receptor (RAGE) levels in the renal cortex of diabetic rats. However, Sar has no effects on the above indices in the normal rats. Therefore, Sar can markedly ameliorate diabetic nephropathy in rats via inhibition of NLRP3 inflammasome activation and AGEs-RAGE interaction.

Anti-proliferative effects of Atractylis lancea (Thunb.) DC. via down-regulation of the c-myc/hTERT/telomerase pathway in Hep-G2 cells.

Atractylis lancea (Thunb.) DC. (AL), an important medicinal herb in Asia, has been shown to have anti-tumor effects on cancer cells, but the involved mechanisms are poorly understood. This study focused on potential effects and molecular mechanisms of AL on the proliferation of the Hep-G2 liver cancer cell line in vitro. Cell viability was assessed by MTT test in Hep-G2 cells incubated with an ethanol extract of AL. Then, the effects of AL on apoptosis and cell cycle progression were determined by flow cytometry. Telomeric repeat amplification protocol (TRAP) assays was performed to investigate telomerase activity. The mRNA and protein expression of human telomerase reverse transcriptase (hTERT) and c-myc were determined by real-time RT-PCR and Western blotting. Our results show that AL effectively inhibits proliferation in Hep-G2 cells in a concentration- and time-dependent manner. When Hep-G2 cells were treated with AL after 48h,the IC50 was about 72.1 µg/ mL. Apoptosis was induced by AL via arresting the cells in the G1 phase. Furthermore, AL effectively reduced telomerase activity through inhibition of mRNA and protein expression of hTERT and c-myc. Hence, these data demonstrate that AL exerts anti-proliferative effects in Hep-G2 cells via down-regulation of the c-myc/hTERT/ telomerase pathway.