Advanced IgA nephropathy with impaired renal function benefits from losartan treatment in rats.

BACKGROUND: Treatment with angiotensin receptor blockers (ARBs) is successful in mitigating IgA nephropathy (IgAN), independent of blood pressure changes, but the therapeutic role of ARB in advanced IgAN with impaired renal function is to be ascertained. The present study was performed to investigate the effect of losartan on advanced IgAN induced by staphylococcal enterotoxin B (SEB) combined with 5/6 nephrectomy in rats. METHODS: Fifty-four male SD rats were randomly divided into three group: Rats in the model group were treated with SEB plus 5/6 nephrectomy, and those in the losartan group were gavaged with losartan (33.3 mg kg(-1 )d(-1)) besides the treatment with SEB plus 5/6 nephrectomy. The urine and blood biochemical changes of rats were tested. IgA, IgG, IgM and C3 depositions were studied dynamically with immunofluorescence. The renal tissue structures were observed under light microscopy. The expressions of TGF-ß1, FN, alpha-SMA and FGF-1 in rat renal tissues were determined with immunohistochemical methods and real-time PCR. RESULTS: At 12 weeks, rats with SEB treatment plus 5/6 nephrectomy showed gradually increased urinary red blood cell (URBC) with a gradual elevation of the 24 h urinary protein, serum BUN and Scr, but losartan treatment lowered the levels of 24 h urinary protein, serum BUN and Scr. A large number of IgA depositions in the mesangial area, glomerulosclerosis and tubulointerstitial fibrosis were found in the model group, and the losartan group showed relieved injury. The expressions of TGF-ß1, FN, alpha-SMA and FGF-1 were significantly elevated in the model. Losartan lessened their expressions. CONCLUSION: Losartan treatment can delay the progression of advanced IgA nephropathy with impaired renal function.

Losartan alleviates renal fibrosis by down-regulating HIF-1α and up-regulating MMP-9/TIMP-1 in rats with 5/6 nephrectomy.

BACKGROUND: This study investigated the effects of losartan intervention on the expressions of hypoxia-inducible factor-1α (HIF-1α), matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinase-1 (TIMP-1) in renal fibrosis in rats with 5/6 nephrectomy. METHODS: Sprague Dawley rats were randomly divided into three groups. Rats in the losartan group were gavaged with losartan (33.3 mg/kg/day) from 1 week after 5/6 nephrectomy, and those in the sham group and the model group only received an equal volume of saline solution by gavage. Rats were sacrificed at the ends of the 4, 8 and 12 weeks, respectively. Urinary N-acetyl-glucosaminidase (NAG), 24-h urinary protein, serum cystatin C, blood urea nitrogen (BUN), and serum creatinine (Scr) levels were assessed. Kidney tissues were observed under light and electron microscope. The expressions of HIF-1α, transforming growth factor-ß1 (TGF-ß1), MMP-9, and TIMP-1 were determined by immunohistochemistry and Western blotting. RESULTS: Twenty-four hour urinary protein, urinary NAG, serum cystatin C, BUN, and Scr levels in the model group were significantly higher than those in the sham group (p < 0.05), but losartan treatment improved these changes. The apparent glomerular sclerosis and tubulointerstitial fibrosis were also found in the model group, which were ameliorated by losartan. The expressions of HIF-1α, TGF-ß1, MMP-9, and TIMP-1 were elevated and MMp-9/TIMP-1 ratio was lowered in the model group (p < 0.05), but losartan increased the expression of MMP-9 and MMp-9/TIMP-1 ratio (p < 0.05) and lessened the expressions of HIF-1α, TGF-ß1, and TIMP-1 (p < 0.05). CONCLUSION: Losartan may ameliorate renal fibrosis partly by down-regulating HIF-1α and up-regulating MMP-9/TIMP-1 in rats with 5/6 nephrectomy.

Taxus chinensis ameliorates diabetic nephropathy through down-regulating TGF-ß1/Smad pathway.

Diabetic nephropathy (DN) is one of the common microvascular complications of diabetes mellitus. Renal fibrosis is closely related to the deterioration of renal function. The present study aimed to investigate protective effect of Taxus chinensis on high-fat diet/streptozotocin-induced DN in rats and explore the underlying mechanism of action. The rat DN model was established via feeding high fat diet for 4 weeks and subsequently injecting streptozotocin (30 mg·kg-1 body weight) intraperitoneally. The rats with blood glucose levels higher than 16.8 mmol·L-1 were selected for experiments. The DN rats were treated with Taxus chinensis orally (0.32, 0.64, and 1.28 g·kg-1) once a day for 8 weeks. Taxus chinensis significantly improved the renal damage, which was indicated by the decreases in 24-h urinary albumin excretion rate, blood serum creatinine, and blood urea nitrogen. Histopathological examination confirmed the protective effect of Taxus chinensis. The thickness of glomerular basement membrane was reduced, and proliferation of mesangial cells and podocytes cells and increase in mesangial matrix were attenuated. Further experiments showed that Taxus chinensis treatment down-regulated the expression of TGF-ß1 and α-SMA, inhibited phosphorylation of Smad2 and Smad3. These results demonstrated that Taxus chinensis alleviated renal injuries in DN rats, which may be associated with suppressing TGF-ß1/Smad signaling pathway.