In vitro suppression of quercetin on hypertrophy and extracellular matrix accumulation in rat glomerular mesangial cells cultured by high glucose.

Quercetin's protective effects on the glomerulosclerosis of diabetic nephropathy (DN) in rat mesangial cells were investigated. The cell cycles, type IV collagen and laminin, TGF-β(1) mRNA, Smad 2/3 and Smad 7, and activities of cell antioxidases were measured. Compared with the high glucose group, quercetin may decrease the cell percentages of G(0)/G(1) phase, Smad 2/3 expression, laminin and type IV collagen, and TGF-β(1) mRNA level significantly. The antioxidant capacity, the cell percentages of S phase and Smad 7 expression was significantly increased by quercetin. These results suggest that quercetin is a protective agent against glomerulosclerosis in DN.

Tang DQ ，Wei YQ ，Yin XX ，Lu Q ，Hao HH ，Zhai YP ，Wang JY ，Ren J ... -  《-》

Protective effects of rutin on rat glomerular mesangial cells cultured in high glucose conditions.

The protective effect of rutin on the glomerulosclerosis of diabetic nephropathy (DN) in rat mesangial cells was investigated. The cultured mesangial cells were divided into eight groups: normal, solvent control, high glucose, low dose of rutin, moderate dose of rutin, high dose of rutin, captopril and Ginkgo biloba extract. The cell cycles, type IV collagen and laminin in cytoplasm, TGF-β₁ mRNA of mesangial cells, Smad 2/3 and Smad 7, and the activities of four antioxidant indexes including T-SOD, MDA, CAT and GSH-Px were measured by flow cytometry, radioimmunoassay, RT-PCR, western blotting and visible spectrophotometry, respectively. Compared with the high glucose group, rutin decreased the cell percentages of the G₀/G₁ phase and inhibited the expression of Smad 2/3, laminin and type IV collagen, and TGF-β₁ mRNA level, significantly. The antioxidant capacity, the cell percentages of S phase and Smad 7 expression were significantly increased by rutin. These results suggest that rutin is a potent protective agent against glomerulosclerosis in DN.

Tang DQ ，Wei YQ ，Gao YY ，Yin XX ，Yang DZ ，Mou J ，Jiang XL ... -  《-》

Ginkgo biloba extract suppresses hypertrophy and extracellular matrix accumulation in rat mesangial cells.

Wang JY ，Yin XX ，Wu YM ，Tang DQ ，Gao YY ，Wan MR ，Hou XY ，Zhang B ... -  《ACTA PHARMACOLOGICA SINICA》

Protective effects of serum containing Ginkgo biloba extract on glomerulosclerosis in rat mesangial cells.

Tang D ，Zhang Z ，Gao Y ，Wei Y ，Han L ... -  《-》

Icariin attenuates high glucose-induced type IV collagen and fibronectin accumulation in glomerular mesangial cells by inhibiting transforming growth factor-β production and signalling through G protein-coupled oestrogen receptor 1.

Icariin has been shown to attenuate diabetic nephropathy in rats by decreasing transforming growth factor-β (TGF-β) and type IV collagen expression, but its mode of action in glomerular mesangial cells is uncertain. The present study aimed to investigate the effect of icariin on excess mesangial type IV collagen and fibronectin accumulation induced by high glucose, and to determine the mechanism underlying its protective effects. Under high-glucose conditions, icariin diminished type IV collagen and fibronectin accumulation, as well as TGF-β production in human and rat mesangial cells. Mesangial cells treated with icariin after TGF-β1 exposure expressed less type IV collagen and fibronectin than those without icariin treatment, suggesting inhibition by icariin of TGF-β1 downstream pathways. On TGF-β1 stimulation, icariin inhibited TGF-β canonical Smad signalling and extracellular signal-regulated kinase (ERK)1/2 signalling by decreasing Smad2/3 and ERK1/2 phosphorylation in a dose-dependent manner. U0126, which blocked the ERK1/2 pathway, exerted an additive effect on the icariin suppression of type IV collagen and fibronectin expression, enhancing the beneficial effects of icariin. The G protein-coupled oestrogen receptor 1 (GPER) antagonist, G-15, abolished the icariin-induced inhibition of type IV collagen, and fibronectin overproduction and TGF-β signalling. Treatment of cells with fulvestrant, a downregulator of the oestrogen receptor, enhanced the action of icariin. In conclusion, icariin decreased type IV collagen and fibronectin accumulation induced by high glucose in mesangial cells by inhibiting TGF-β production, as well as Smad and ERK signalling in a GPER-dependent manner.

Li YC ，Ding XS ，Li HM ，Zhang C ... -  《-》