Ramipril can alleviate the accumulation of renal mesangial matrix in rats with diabetic nephropathy by inhibiting insulin-like growth factor-1

Abstract Purpose: To investigate the impact of Ramipril (RAM) on the expressions of insulin-like growth factor-1 (IGF-1) and renal mesangial matrix (RMM) in rats with diabetic nephropathy (DN). Methods: The Sprague Dawley rats were divided into normal control (NC) group (n = 12), DN group (n = 11), and DN+RAM group (n = 12). The ratio of renal weight to body weight (RBT), fasting blood glucose (FBG), HbA1c, 24-h urine protein (TPU), blood urea nitrogen (BUN), creatinine (Cr), renal pathological changes, the levels of IGF-1, fibronectin (FN), type IV collagen (Col-IV), and matrix metalloproteinases (MMP)-2 were compared among the groups. Results: Compared with NC group, the RBT, FBG, HbA1c, TPU, BUN, Cr, and RMM in DN group were significantly increased (P < 0.05), the IGF-1, FN, and Col-IV were significantly upregulated (P < 0.05), while MMP was significantly downregulated (P < 0.05). Compared with DN group, the indexes except for the FBG and HbA1c in DN+RAM group were significantly improved (P < 0.05), among which IGF-1 exhibited significant positive correlation with TPU(r=0.937), FN(r=0.896) and Col-IV(r=0.871), while significant negative correlation with MMP-2 (r=-0.826) (P<0.05). Conclusion: RAM may protect the kidneys by suppressing IGF-1 and mitigating the accumulation of RMM.

Shenhua Tablet inhibits mesangial cell proliferation in rats with chronic anti-Thy-1 nephritis

BACKGROUND: In China, mesangial proliferative glomerulonephritis (MsPGN) is one of the most common kidney diseases. In this study, we treated a rat model of chronic anti-Thy-1 MsPGN with Shenhua Tablet and evaluated whether the tablet was able to protect the kidney function. Thirty-six Wistar rats were randomly divided into six groups: (1) Sham surgery (Sham); (2) anti-Thy-1 nephritis model (Thy-1); (3) anti-Thy-1 nephritis model + irbesartan-treated (Irb); (4) anti-Thy-1 nephritis model + low-dose of Shenhua Tablet (SHL); (5) anti-Thy-1 nephritis model + medium-dose of Shenhua Tablet (SHM); (6) anti-Thy-1 nephritis model + high-dose of Shenhua Tablet (SHH). RESULTS: Thirteen weeks after drug treatment, urinary proteins were quantified and renal pathological changes were thoroughly examined at the time point of 24 h. Meanwhile, the expression levels of p-Erk1/2, cyclin D1 and p21 at the renal cortex were also tested. The levels of urinary proteins and total cholesterol in the blood were significantly reduced in rats treated with any drug tested in this study. The level of triglyceride was significantly reduced in all three Shenhua Tablet-treated groups. Renal pathomorphological scores were significantly improved in groups of Irb, SHM and SHH. Mesangial cell proliferation was significantly inhibited in any drug-treated group. p-Erk1/2 and cyclin D1 were downregulated whereas p21 was upregulated in the renal cortex. CONCLUSIONS: Our study indicated that Shenhua Tablet is able to inhibit the abnormal proliferation of mesangial cells and to prevent kidney damage, which is likely associated with downregulation of p-Erk1/2 and reduced activity of its downstream target-cyclin D1.

The effect of hypoxia and reoxygenation in the response of mesangial cells to angiotensin II in vitro / Efeito da hipóxia e reoxigenação na resposta à angiotensina II em células mesangiais in vitro

INTRODUCTION: Mesangial cells (MC) may be involved in the glomerular alterations induced by ischemia/reperfusion injury. OBJECTIVE: To evaluate the response of immortalized MC (IMC) to 30 minutes of hypoxia followed by reoxygenation periods of 30 minutes (H/R30) or 24 hours (H/R24). METHODS: The intracellular calcium concentration ([Ca+2]i) was measured before (baseline) and after adding angiotensin II (AII, 10-5 M) in the presence and absence of glybenclamide (K ATP channel blocker). We estimated the level of intracellular ATP, nitric oxide (NO) and PGE2. RESULTS: ATP concentration decreased after hypoxia and increased after reoxygenation. Hypoxia and H/R induced increases in basal [Ca+2]i. AII induced increases in [Ca+2]i in normoxia (97 ± 9%), hypoxia (72 ± 10%) or HR30 (85 ± 17%) groups, but there was a decrease in the response to AII in group H/R24 since the elevation in [Ca+2]i was significantly lower than in control (61 ± 10%, p < 0.05). Glybenclamide did not modify this response. It was observed a significant increase in NO generation after 24 hours of reoxygenation, but no difference in PGE2 production was observed. Data suggest that H/R injury is characterized by increased basal [Ca+2]i and by an impairment in the response of cells to AII. Results suggest that the relative insensibility to AII may be at least in part mediated by NO but not by prostaglandins or vasodilator K ATP channels. CONCLUSION: H/R caused dysfunction in IMC characterized by increases in basal [Ca+2]i during hypoxia and reduction in the functional response to AII during reoxygenation.

INTRODUÇÃO: Células mesangiais (CM) podem estar envolvidas na lesão glomerular induzida por hipoxia/reperfusão (H/R). OBJETIVO: Avaliar a resposta de CM imortalizadas (CMI) à hipoxia por 30 minutos seguida de reoxigenação por 30 minutos (H/R30) ou 24 horas (H/R24). MÉTODOS: Concentração de cálcio intracelular ([Ca+2]i) foi avaliada antes (basal) e após a adição de angiotensina II (AII, 10-5 M), na presença e na ausência de glibenclamida (bloqueador de canais K ATP). Foram estimados o nível de ATP intracelular, de óxido nítrico (NO) e de PGE2. RESULTADOS: Nível de ATP diminuiu após hipóxia e aumentou após a reoxigenação. H/R induziu aumento na [Ca+2]i basal. A AII elevou a [Ca+2]i nas condições de normoxia (97 ± 9%), hipoxia (72 ± 10%) ou HR30 (85 ± 17%), porém no grupo H/R24, houve diminuição significativa na resposta à AII, uma vez que a elevação da [Ca+2]i foi mais baixa do que no controle (61 ± 10%, p < 0,05). Glibenclamida não alterou esta resposta. Houve um aumento significativo na geração de NO após 24 horas de reoxigenação, mas não foi observada nenhuma diferença na produção de PGE2. Os dados indicam que a injuria celular causada pela hipoxia/reoxigenação é caracterizada pelo aumento na [Ca+2]i basal e por uma diminuição na reatividade celular à AII. Resultados sugerem que a insensibilidade ao agonista constritor pode ser pelo menos em parte, mediada pelo NO, mas não pelas prostaglandinas ou por canais K ATP. CONCLUSÃO: H/R resultou em disfunção das CMI, caracterizada pelo aumento na [Ca+2]i basal durante a hipóxia e redução da resposta funcional a AII durante a reoxigenação.

TGF-beta1-induced PINCH-1-ILK-alpha-parvin complex formation regulates mesangial cell proliferation and hypertrophy

TGF-beta1-induced glomerular mesangial cell (GMC) injury is a prominent characteristic of renal pathology in several kidney diseases, and a ternary protein complex consisting of PINCH-1, integrin-linked kinase (ILK) and alpha-parvin plays a pivotal role in the regulation of cell behavior such as cell proliferation and hypertrophy. We report here that PINCH-1-ILK-alpha-parvin (PIP) complex regulates the TGF-beta1-induced cell proliferation and hypertrophy in cultured rat GMCs. When GMCs were treated with TGF-beta1 for 1, 2 and 3 days, the PIP complex formation was up-regulated after 1 day, but it was down-regulated on day 2. Cell numbers were significantly elevated on day 2, but dramatically decreased on day 3. In contrast, a significant increase in cellular protein contents was observed 3 days after TGF-beta1-treatment. TGF-beta1 induced early increase of caspase-3 activity. In GMCs incubated with TGF-beta1 for 2 days, cytosolic expression of p27(Kip1) was dramatically reduced, but its nuclear expression was remarkably elevated. A significantly decreased expression of phospho-Akt (Ser 473) was observed in the cells treated with TGF-beta1 for 1 day. TGF-beta1 induced early increase of phospho-p27(Kip1) (Thr 157) expression with subsequent decrease, and similar responses to TGF-beta1 were observed in the p38 phosphorylation (Thr 180/Thr 182). Taken together, TGF-beta1 differently regulates the PIP complex formation of GMCs in an incubation period-dependant fashion. The TGF-beta1-induced up- and down-regulation of the PIP complex formation likely contributes to the pleiotropic effects of TGF-beta1 on mesangial cell proliferation and hypertrophy through cellular localization of p27(Kip1) and alteration of Akt and p38 phosphorylation. TGF-beta1-induced alteration of the PIP complex formation may be importantly implicated in the development and progression of glomerular failure shown in several kidney diseases.