The Effect Of Tujian Mixture On Phenotypic Modulation Of Mesangial Cells In Diabetic Rats

Background The major event in the pathologic change of diabetic nephropathy is accumulation of extracellular matrix (ECM) in glomeruli. However, its cytologic background is unclear. Phenotypic modulation of mesangial cells in proliferative glomerulonephritis is correlative to ECM accumulation in glomeruli. As a non-proliferative glomerulopathy, it is unclear whether phenotypic modulation of mesangil cells exist in diabetic nephropathy at present. The aim of this study was to evaluate phenotypic modulation of mesangial cells in streptozotocin-induced diabetic rats with unilateral nephrectomy and the relationship between the phenotypic modulation of mesangial cells and the ECM accumulation in glomeruli. The effects of Tujian mixture (a Chinese herbal medicine), valsartan and tetrandrine on it were also investigated. Methods After the left kidney was resected, diabetes mellitus model was induced with a single dose injection of streptozotocin (STZ,45mg/kg) intraperitoneally in Sprague- Dawley rats. The diabetic rats were divided into four group: diabetes mellitus (DM group, n=8), valsartan treatment (VT group, n=8), Tujian mixture treatment (ZY group) and tetrandrine treatment group (HJ group). Another 8 rats with unilateral nephrectomy but without STZ injection (QC group) and 8 age-match normal rats (ZC group) were as controls. At day 4 after STZ injection, VT group, ZY group and HJ group began to be given valsartan (20mg/kg/d), Tujian mixture (20g/kg/d) and tetrandrine (40mg/kg/d) for 12 weeks respectively. After 12 weeks following treatment, all rats were sacrificed. The morphologic changes in rugular pathological section were observed. The expression of α -smooth muscle actin (α -SMA), proliferative cell nuclear antigen(PCNA), collagen type Ⅳ(Coll Ⅳ), transforming growth factor- β 1 (TGF- β 1) , matrix metalloproteinase-9(MMP-9) and tissue inhibitor of metalloproteinase-1(TIMP-1) proteins within glomeruli were examined by immunohistochemistry. The mesangium and basement membrane area in PAS stain section, α -SMA positive area, coll Ⅳ, TGF- β 1, MMP-9, TIMP-1 per glomerular tuft area were calculated by computer-assisted image analysis system. The correlations between the α -SMA positive area per glomerular tuft to other examination parameters were analyzed by the method of bivariate Pearson correlation analysis in SSPS soft. Results At 12 weeks following STZ injection, the 24 hours urine protein excretion in DM group rats was significant higher than NC and QC group. Segmental increasing width of mesangial area without cellular proliferation, increasing ECM in glomeruli were observed in DM group rats. The α -SMA positive staining was trace in a few glomeruli in NC and QC group rats. While the α -SMA positive staining in glomeruli was pronounced in DM group rats. But the number of PCNA positive cells was not different between DM rats and NC rats, or QC rats. The mesangium and basement membrane area per glomerulus in PAS stain section, TGF- β 1, Coll Ⅳ positive area...