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Aerobic glycolysis is a metabolic process in which cellular energy production favors the low-efficiency energy-producing glycolytic pathway in the presence of sufficient oxygen, reducing dependence on aerobic respiration, while producing energy rapidly and providing advantages for cell survival and proliferation. In recent years, several studies have shown that aerobic glycolysis is involved in the development of renal interstitial fibrosis (RIF) and involves various cell types such as fibroblasts, endothelial cells, renal tubular epithelial cells, pericytes, and inflammatory cells. Drugs targeting glycolysis may provide new ideas for the prevention and treatment of RIF. This article reviews the research progress of abnormal aerobic glycolysis in different cells and glycolytic intervention drugs in RIF.
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Objective To investigate the roles of microRNA-382 (miR-382) in the pathogenesis of renal tubulointerstitial fibrosis (TIF).Methods Human kidney epithelial cells (HK2)transfected with miR-382 inhibitor (antagomiR-382) were used to examine the effect of miR-382 abundance on cell polarity,as well as to test the complementary relationship between miR-382 and its predicted target gene heat shock protein 60 (HSPD1),which was further verified by 3'-untranslated region luciferase assay and site-directed mutagenesis.The role of miR-382 played in the development of renal interstitial fibrosis and redox regulation was examined in a mouse unilateral ureteral obstruction (UUO) model.Locked nucleic acid (LAN)-modified anti-miR-382 was intravenous delivered via tail vein 30 min prior to UUO,and repeated the dosage 24 h after the surgery.For clinical verification,renal biopsy specimens from 12 IgA nephropathy (IgAN) patients were collected,6 patients with moderate to severe TIF and 6 patients without TIF.The relative abundance of miR-382 and HSPD1 protein was analyzed by using in situ hybridization and immunohistochemistry.Results HSPD1 was confirmed to be a new,direct target gene of miR-382 by in vitro 3'-untranslated region luciferase assay and sitedirected mutagenesis.The development of epithelial transition in HK2 cells was accompanied with upregulation of miR-382 [(6.54±0.96) vs (1.12±0.26),P ＜ 0.05].Blocking the expression of miR-382 could reversed the progression of epithelial transition partially.In UUO mice the abundance of miR-382 was up-regulated [(6.89 ± 2.47) vs (1.00±0.42),P ＜ 0.01] while HSPD1 and Trx were downregulated compared with the sham group.Down-regulation of miR-382 was associated with significant decrease in TIF,but increase in HSPD1 and thioredoxin protein compared with UUO group [HSPD1:(0.34±0.10) vs (0.14±0.05);Trx:(0.79±0.18) vs (0.36±0.16);all P ＜ 0.05].The expression of miR-382 was up-regulated and HSPD1 was significantly down-regulated in IgAN patients with TIF.Conclusions miR-382 play an important role in renal tubulointerstitial fibrosis in human and mice.HSPD1 is one of the target genes of miR-382.The down-regulation of HSPD1 and the decrease ability of anti-oxidative stress may be the important mechanism of miR-382 involved in renal tubulointerstitial fibrosis.
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Objective To study the effect of valsartan, an angiotensin II type I receptor antagonist AT1RA), on renal interstitium fibrosis(RIF)in rats with unilateral ureteral obstruction (UUO), and to discuss the possible mechanisms. Methods Thirty-five Sprague-Dawley rats were randomly divided into sham-operation, model and valsartan groups. The rat UUO model was established. From the day after operation, the rats in sham-operation and model groups received intragastric valsartan and sodium chloride in tales doses. The serum creatinine (SCr), blood urea nitrogen (BUN), angiotensin- II (Ang II ) in blood plasma, N-acetyl-β-D-glucosaminidase(NAG)and 24 h urine β2-microglobulin(β2-MG)were examined 4 weeks after operation. The renal tissues of the obstructed sides were harvested; H-E staining and Masson staining were used to observe the tubulointerstitial lesions; and immunohistochemistry staining was used for semiquantitative analysis of alpha-smooth muscle actin(α-SMA), fibronectin(FN), plasminogen activator inhibitor-1 (PAI-1), transforming growth factor-beta 1 (TGF-β1), and hepatocyte growth factor(HGF). Results Compared with those in the sham-operation group, SCr, BUN, Ang II, NAG and (β2- MG levels, and the expression of α-SMA, FN, PAI-l, and TGF-β1 in model group were significantly higher(P0. 05). The expression levels of orSMA, FN, PAI-l, and TGF-β1 in valsartan group were significantly lower than and the expression of HGF was significantly higher than those in the model group(P<0. 01). Conclusion Valsartan does not improve the tubular and glomerular functions, but it can inhibit production of Ang-II. Valsartan may inhibit renal interstitial fibrosis by inhibiting renal tubule epithelial mesenchymal transdifferentiation and reducing extracellular matrix deposition through blocking up Ang Q, inhibiting overexpression of α-SMA, FN, PAI-l, and TGF-β1, and inducing the HGF expression.
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Objective To study the role of JAK-STAT singal transduction pathway in the interstitial fibrosis of unilateral ureter obstruction (UUO)mice. Methods Mice UUO model was established and the phosphorylation of JAK-STAT was examined at day 1,4,7 and 14 after ligation of the ureter.Mice in the treatment group were treated with daily injection of selective JAK2 inhibitor AG490 starting 2 h before ureter ligation until sacrifice while vehicle alone was given to mice in the model control group.Mice were sacrificed at day 14 after the establishment of model.Renal tubular lesion and interstitial fibrosis were assessed on paraffin section.Immunohistochemistry was used to detect renal macrophage infihration and α-SMA expression.The expression of collagen Ⅲ and MCP-1 mRNA was measured by RT-PCR.Phosphorylation of JAK2and STAT1 was examined by Western blotting. Results JAK2-STAT1 signaling transduction pathway was activated in UUO model.The activation of JAK2-STAT1 was closely correlated with the progression of renal injury,tubular histological lesions and interstitial fibrosis.AG490 treatment significantly inhibited the phosphorylation of JAK2 and STAT1 (P＜0.01).AG490 treatment also significantly reduced tubular lesions[(21.7 ±1.7)% vs (49.4±1.0)%]and interstitial fibrosis(1.0±0.1 vs 2.3±0.2),α-SMA expression(0.9±0.1 vs 2.1±0.2)and maerophage accumulation[(13.3±1.6)cells/HPF vs (34.4±1.0)cells/HPF](all P＜0.01).In addition,AG490 significantly inhibited the expression of collagen Ⅲ and MCP-1 mRNA. Conclusion JAK-STAT signaling plays an important role in renal tubulointerstitial inflammation and fibrosis.
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Objective To study the tissue pathology and the expression of related factors during renal tubular-interstitial fibrosis in aristolochic acid (AA) nephropathy in rat. Methods 46 male Wistar rats were randomly divided into 2 groups. The test group consisted of 26 rats which were gavaged with the extract of Caulis Aristolochiae Manshuriensis (CAM) (AA 20mg?kg -1 ?d -1 ); the control group consisted of 20 rats which were given with equal volume of potable water. At the end of 4th, 8th, 12th week, the kidneys of each rat were separately harvested. The HE, PAS and Masson staining were used to analyze the degree of tubular damage and interstitial fibrosis, and immunohistochemical method was applied to assess the protein expression of proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), transforming growth factor-?_1 (TGF-?_1) in the renal specimens. The mRNA expression of VEGF, endothelin-1 (ET-1), bone morphogenetic protein-7 (BMP-7) in renal tissue were determined by RT-PCR respectively. Results A severe renal tubular-interstitial damage and an early fibrosis were observed at the end of 12th week, and the interstitial fibrotic area was 31.36%. The protein expression of PCNA was increased at 4th week, but down-regulated after 8th week; the expression of TGF-?_1 and VEGF was increased at 4th week, while TGF-?_1 was maintatined on a high level with passage of time, but VEGF decreased gradually. The mRNA expression of VEGF and ET-1 increased notably at 4th week, slightly decreased after 8th week, but maintained at a high level. The BMP-7 declined slowly with the progression of pathological changes, reaching its lowest level at 12th week. Conclusion The mechanism of the rapid progression of fibrosis in AAN might be the renal result of severe impairment of regeneration of epithelial cells, lowering of expression of factors of promoting repair and inhibiting fibrosis, while the expression of factors of promoting fibrosis was maintained at a highlevel.
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Objective To investigate the pathological characters of capillaries in tubulointerstitial nephropathy,and to study the expression of vascular endothelial growth factor(VEGF)and proliferation cell nuclear antigen(PCNA)in capillary endothelial cells in aristolochic acid-induced nephropathy in rat.Methods 46 male Wistar rats were randomly divided into 2 groups,the model group was composed of 26 rats which were gavaged with the extract of Caulis Aristolochiae Manshuriensis(aristolochic acid AA 20mg/kg?d),and the control group consisted of 20 rats which were treated with equal volume of potable water.The rats were sacrificed in batches at the end of 4th,8th and 12th weeks,and the blood samples were collected from abdominal aorta for the tests of renal functions.The kidney of each rat was harvested.The renal tissues were stained with HE,PAS,and Masson's technique for the analysis of degree of tubulointerstitial injury,interstitial fibrosis,and peritubular capillary(PTC),and the expressions of both VEGF and PCNA were morphologically observed and immunohistochemically analyzed.Results In the model group,the level of serum creatinine/body weight increased markedly,the renal pathological changes consisted of severe acute renal tubulointerstitial damage with cloudy swelling of tubule,degeneration,and exfoliation.With prolongation of feeding time,the damage progressively aggravated,and showed a remarkable tubulointerstitial injury.The interstitial fibrosis area was 31.36% at the end of 12th week.The renal capillaries showed thickening of vessel wall,narrowing of the vessel cavity,obstruction or hyalinization of some capillaries.There was focal infiltration of inflammatory cells around the injured vessels.But there was no apparent change in the globules compared with that in control group.The PTC dwindled in caliber or distorted,and the PTC density decreased significantly in models,especially in the region of tubular damage or interstitial fibrosis.The expression of VEGF showed compensatory up-regulation at the 4th week,but it was down-regulated gradually.The expression of PCNA was up-regulated at the 4th week,but down-regulated after 8th week,and only a few basement membrane naked tubular cells showed positive expression at 12th week.Conclusion AA could induce injury and loss of capillaries of the kidney.The decrease in capillary density might contribute to the impairment of renal function and progressive interstitial fibrosis,and the relative deficiency of VEGF expression may be related to PTC injury,which is one of the causes of chronic progression of aristolochic acid nephropathy.
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Objective To evaluate the effect and mechanism of HMG-CoA reductase inhibitor simvastatin on experimental interstitial fibrosis. Methods Experiments on rat 5/6 nephrectomy chronic renal failure model and primary cultured renal interstitial fibroblast cells were conducted in this study. The cell proliferation, extracellular matrix, c-fos mRNA expression of rat interstitial fibroblasts were measured by MTT assay, immunohistochernitry, semi-quantitative reverse-transcript PCR methods, respectively. Results Serum cholesterol, triglyceride and creatinine of treated group were significantly reduced by simvastatin as compared with controls. No statistical significance in BUN was observed between untreated and simvastatin-treated rats. Histological examination revealed that simvastatin caused a reduction in the glomeruli with sclerosis. Tubulointerstitial injury paralleled the degree of glomerular damage. Simvastatin in a dose-dependent manner inhibited the proliferation of renal intersititial fibroblasts, decreased the secretion of lamimn( LN), and suppressed the expression of c-fos mRNA, as compared with normal controls. No obvious effect on hyaluronic acid( HA) secretion of fibroblasts was found. Conclusions Simvastatin is anti-proliferative in interstitial fibroblasts and decreases the secretion of laminin. This effect is exerted, at least in part, via inhibition of the c-fos and c-jun-dependent mitogenic pathway. Simvastatin may prevent interstitial fibrosis development and attenuate renal damage in uremic rats with hvperlipidemia.
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Objective To explore the role of type 1 plasminogen activator inhibitor (PAI-1 ) in mediating renal tubulointerstitial injury of patients with IgA nephropathy. Methods The mRNA and protein production of PAI-l in renal tubulointerstitium were defected using in stiu hybridization and immunohistochemistry. Detections of antigens of ?-smooth muscle actin(?-SMA) and proliferating cell nucleus antigen (PCNA) were also performed. Results PAI-l was normally expressed in the walls of vessels and distal tubules, but significantly increased in lesions of IgA nephropathy, including crescents, Bowman capsules and tubulointerstitial infiltrating cells. There was lithe expression of PAl-1 in the glomerular capillary tufts. The renal expression of PAI-l was significantly correlated with serum creatinine (P
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Objective To establish a model of chronic aristolochic acid nephropathy (CAAN) in rats and to investigate the pathogenesis of its renal interstitial fibrosis.Methods Male Sprague-Dawley rats were randomly divided into two groups. One group received extract of Aristolochia manshuriensis Kom by gavage intermittently as model group. Another group received only tap water by gavage as controls. Six rats in each group were sacrificed at the end of 4th, 8th and 12th week respectively and the kidneys of each rat were separately harvested. The mRNA and protein expression of type I collagen (Col I ), transforming growth factor-?1 (TGF-?1), connective tissue growth factor (CTGF), plasminogen activator inhibitor-1 (PAI-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) was detected by real-time quantitative RT-PCR and immunohistochemical staining respectively. Results The mRNA expression of Col I, TGF-?1, CTGF, PAI-1 and TIMP-1 in kidney tissue of the rats in model group was significantly upregulated compared to that in controls at the end of 4th week (9.31-, 5.16-, 1.79-, 8.66- and 2.54-fold, respectively) (P
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Objective To investigate the relationship between tubular cells transdifferentiation and renal interstitial fibrosis in patients with chronic aristolochic acid nephropathy (CAAN). Methods Specimens from renal biopsies of 10 CAAN patients with serum creatinine level of (309. 41 ? 164. 44) ?mol/L were performed to examine the extent of renal interstitial fibrosis by Masson staining, the expression of collagen types Ⅰ and Ⅲ by sirius red staining, and the expression of cytokeratin(CK), ?-smooth muscle actin (a-SMA), vimentin (Vim) and transforming growth factor-? 1 (TGF-?1) by immunohistochemical staining. Quantitative analysis by computer image analytic system or semi-quantitative analysis were used to evaluate the data. Results There was positively significant correlation between interstitial collagen types Ⅰ and Ⅲ and serum creatinine level ( r =0. 890, P
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Objective To examine the expression of cell cycle regulatory protiens in renal tubulointerstitial cells of human glomerulonephritis. Methods Immunohisochemieal studies were performed on 19 specimen from renal biopsy to detect cyclin Dl, cyclin A, p21 and proliferating nuclear antigen (PCNA) . Results Cyclin Dl, cyclin A and p21 were positive in some of tubulointerstitial cells, and showed significant correlations with positive PCNA cells. The numbers of tubular positive cells in both groupsofⅠand Ⅱ degree of histopathological change were more than those of other groups. The numbers of interstitialpositive cells showed significant correlations with the degree of tubulointerstitial histopathological change and the value of urine NAG. Conclusion Cell cycle regulatory proteins regulate the proliferation of tubular and interstitial cells, and correlate with the interstitial fibrosis.
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Objective To study the role of fibroblasts in the pathomechanisms of renal interstitial fibrosis(RIF). Methods Growth behavior and apoptos, of renal interstitial fibroblasts in cultures, established using renal biopsies of casts with and without RIF, were studied. Results There were significant alterations in the growth behavior, the differentiation pattern of potentially mitotic fibroblast populations and programmed cell death in cultures derived from kidneys with RIF, as compared with cultures of normal origin. Conclusion The abnormal growth and apoptosis of fibroblasts may play an im-portant role in RIF. Inhibiting the proliferation and promoting the programmed death of fibroblasts may be benificial to patients with RIF.
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Objective To investigate the relationship of up-regulated thrombospondin 1 (TSP-1) expression with renal interstitial fibrosis and peritubular capillary loss in chronic aristolochic acid nephropathy(CAAN). Methods Thirty-six male SD rats were randomly divided into two groups, 18 in each one. CAAN rats received 20 mg?kg-1?d-1 aristolochic acid (AA) contained in ethanol extract of Aristolochia manshuriensis Kom by gavage for 5 days in the 1st week, and after a break of 9 days, then 15 mg?kg-1?d-1 AA for 7 days in every other week up to the 12th week. Control group rats (Con) only received tap water by gavage as above. At the end of the 4th, 8th and 12th week, 6 rats in each group were sacrificed. Immunohistochemical staining was performed in rat renal tissue sections to examine the expression of TSP-1, transforming growth factor-?1 (TGF-?1), aminopeptidase P(APP), vascular endothelial growth factor (VEGF) and type I collagen (Col I ). Results Compared with Con, the expression levels of interstitial TSP-1, tubular TGF-P1 and interstitial Col I were all up-regulated in CAAN rats (all P
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Objective To investigate the effects of glycyrrhizin-18? on the expressions of connective tissue growth factor (CTGF) and transforming growth factor-?1 (TGF-?1) in renal interstitium in rats with obstructive nephropathy. Methods A total of 100 Wistar rats were divided into experiment group (include prophylaxis group with glycyrrhizin-18?, glycyrrhizin-18? treatment group, and group with normal saline) and control group (sham operation group). Models of rats with obstructive nephropathy were established by unilateral ureteral ligation. The rats were sacrificed at 7, 14, 28, and 56 d after operation and specimens were taken from the renal cortex. The morphopathological changes in the renal interstitium were observed byr light and electron microscopy. CTGF, TGF-?1, and collagen type Ⅲ were detected by immunohistochemical staining. The measured data were evaluated by EIG image analysis system. Results In the renal interstitium, there was progressive fibrosis in the model. Semi-quantitative analysis indicated that the expression levels of CTGF, TGF-?1, and collagen type Ⅲ in the renal interstitium in glycyrrhizin-18? treatment and prophylaxis groups were markedly higher than those in the sham operation group (P0.05). The expression of CTGF in the renal interstitium was closely correlated with those of TGF-?1 and collagen type Ⅲ (P
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Objective To study the effect of Benazepril on the renal connective tissue growth factor(CTGF) expression and interstitial fibrosis in unilateral ureteral obstruction(UUO) rats and to illuminate the possible mechanisms.Methods 24 Sprague-Dawley rats were randomly divided into Sham-operated,control and Benazepril groups.From the day before operation,the rats were under intragastric administration of Benazepril 10mg/(kg?d) in Benazepril group,and sodium chloride in tales doses in Sham and control groups.On the 14~(th) day after operation,the obstructed kidney was taken out to be measured by HE,Masson,and immunohistochemistry staining for TGF-?_1,CTGF,?-SMA and ColⅢ.Results The score of renal interstitial lesion and fibrosis index in Benazenpril were significantly lower than those in the control group(P
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Objective To investigate the protective function of oxymatrine on the renal intestitial fibrosis in rats.Methods Forty male Sprague Dawley rats were randomly divided into 5 groups: sham group,model group,Lotensin group,large-dose oxymatrine group,and small-dose oxymatrine group.The models were established by unilateral ureteral obstruction(UUO) of the left side.On the 14~(th) day after operation,the obstructed kidney was taken out.Then,HE,Massion,and immunohistochemistry staining of transforming growth factor-?_(1)(TGF-?_(1)),(?-smooth) muscle acting(?-SMA) and collagen Ⅲ were conducted.After that,semiquantitative analysis was performed.Results After oxymatrine,treatment,the expressions of ?-SMA,TGF-?_(1) and ColⅢ of the obstructed kidney in the treatment group were significantly lower than those in the model group(P0.05).Conclusion Oxymatrine may reduce the expression of cytokines such as TGF-?_(1),then the activation of cell producing ECM and then the sendimentation of ECM,thus preventing renal interstitial fibrosis.