Changes of aquaporin 4 expression after hepatic ischemia-reperfusion injury in rats

AIM: To study the relationship between the changes of aquaporin 4 (AQP4) expression and the liver functions in the process of hepatic ischemia-reperfusion (I/R) injury in rats. METHODS: Forty-eight Wistar rats were used to establish the animal model of hepatic I/R injury. The rats were subject to ischemia for 30 min and were randomly divided into 4 groups according to the time of reperfusion: 2 h group, 1 day group, 3 days group and 7 days group. The corresponding control animals were also set up. The serum was collected for detecting direct bilirubin (DB), indirect bilirubin (IB) and alanine transaminase (ALT). The pathological changes of the liver tissues were observed under microscope with HE staining. The protein expression of AQP4 was measured by the method of immunohistochemistry and the mRNA expression of AQP4 was detected by RT-PCR. RESULTS: Under microscope, degeneration and necrosis of the hepatic cells were observed in the liver tissues in I/R injury groups. Compared with sham operation group, the concentrations of DB, IB and ALT activity in I/R injury groups increased obviously, peaking on the first day after operation, then declining continuously and restoring to the normal levels on the 7th day after operation. The expression of AQP4 were significantly decreased in I/R injury animals in 2 h group, 1 day group and 3 days group, and reached the minimum level on the first day. The mRNA expression levels of AQP4 were also deceased in hepatic I/R injury rats in 2 h group, 1 day group and 3 days group, and reached the minimum level on the first day after operation, then increased slowly and restored to the normal levels on the 7th day after operation. CONCLUSION: Hepatic ischemia-reperfusion induces a decrease in AQP4 expression and impairs the liver functions, indicating an important role of AQP4 in the pathogenesis of liver ischemia-reperfusion injury.     

Effect of aquaporin 4 on lymphatic brain edema in rats

AIM：To investigate the role of aquaporin 4 (AQP4) in the formation and elimination of lymphatic brain edema (LBE). METHODS：Sprague-Dawley rats were randomly divided into sham group and LBE group. LBE was induced by ligating bilateral cervical lymphatic tubes and removing the corresponding lymphatic nodes. The water contents in the cerebral cortex were measured by wet-dry weight method. The expression of AQP4 in the cerebral cortex was detected 1 d, 3 d, 7 d, 11 d and 15 d after a cervical lymphatic blockade or a sham operation by immunohistofluorescence staining and Western blotting. Furthermore, correlation analysis was made between the protein expression of AQP4 and the brain water content. RESULTS：Compared with sham group, cerebral water content, and the protein expression of AQP4 in the LBE rats increased significantly 3 d after operation, peaked at 7 d, followed by gradually stepping down. Furthermore, the expression of AQP4 was positively correlated with brain water content (r=0.8024, P<0.05). CONCLUSION：AQP4 may play an important role in the formation and elimination of LBE.     

Effect of renal denervation by radiofrequency catheter ablation on expression of aquaporins in dog kidneys

AIM: To investigate the effect of renal denervation (RDN) by radiofrequency catheter ablation on the expression of aquaporins (AQP) in dog kidneys.METHODS: Adult Chinese Kunming dogs (n=12) were randomly divided into RDN group and control group (6 for each group). The dogs in RDN group underwent bilateral RDN using radiofrequency catheter ablation, and radiofrequency catheter was positioned in bilateral renal artery without ablation in control group. The levels of norepinephrine (NE) and AQP1~3 in the renal tissues were detected 1 month after RDN, and blood pressure (BP) measurements were performed at baseline and 1 month after RDN.RESULTS: The level of NE in RDN group was significantly lower than that in control group (P<0.01). The expression of AQP1~3 in the renal cortex and medulla was lower in RDN group than that in control group. RDN also caused a substantial BP reduction (P<0.05). CONCLUSION: RDN substantially decreases the tissue levels of NE and AQP in dog kidneys, and also decreases BP significantly, which might be involved in the mechanism of BP reduction by RDN. Renal sympathetic nerve plays an excitatory role in the regulation of AQP in the kidney.     

Effect of inhaled nitric oxide on aquaporin expression in newborn rat lung in acute hyperoxic lung injury

AIM:To investigate the effect of inhaled nitric oxide on aquaporin expression and alveolar epithelial fluid transport in newborn rats with acute hyperoxic lung injury. METHODS:32 newborn SD rats were randomized to breathe for 48 h room air (C), >95%O₂ (O), >95%O₂+10^-5 NO (NO only in the first 24 h, ONO), room air + NO (CN). Then, the rats were killed, the lung wet-to-dry weight ratio (Q_W/Q_D), the histology, and AQP1, AQP5, α₁-NKA, α-ENaC mRNA expressions in the lungs were measured. RESULTS:Compared with C group, the Q_W/Q_D in O group significantly increased (P<0.01), and AQP1 mRNA expression decreased significantly (P<0.01). Compared with O group, ONO group had a lower level of Q_W/Q_D (P<0.05), and AQP1 mRNA expression increased (P<0.05). AQP5 mRNA expression in all groups remained unchanged. CONCLUSION:In newborn rats with acute hyperoxic lung injury, inhaled 10-5 nitric oxide for 24 h may attenuate lung edema and increase AQP1 mRNA expression, suggesting that inhaled 10^-5 nitric oxide for 24 h may promote the AQP1 expression in lung in this model of acute lung injury.     

Expression of aquaporin 3 in human prostate

AIM: To determine the expression of aquaporin 3 (AQP3) in transitional and peripheral zone of human prostate tissue.METHODS: AQP3 mRNA expression was analyzed in five prostate tissues by RT-PCR. AQP3 protein expression and localization were characterized by Western blotting and immuno-staining with polyclonal anti-AQP3 antibody.RESULTS: The results of RT-PCR and Western blotting showed that AQP3 was expressed in transitional and peripheral zone of prostate tissue. The AQP3 protein expression in transitional zone was higher than that in peripheral zone. The results of immuno-staining indicated that AQP3 protein was expressed in secretory cells of prostate.CONCLUSION: The AQP3 was expressed in prostate tissue, suggesting that AQP3 play an important role in the secretion of prostate liquid.     

Effect of CHOP expression knock-down on apoptosis of renal tubular epithelial cells

AIM:To study the effect of C/EBP homologous protein (CHOP) on the apoptosis of renal tubular epithelial HK2 cells. METHODS:The serum mRNA levels of CHOP in the patients with acute kidney injury and healthy controls were detected by qPCR. In vitro, renal tubular epithelial HK2 cells were divided into control group, negative group (transfected with negative control siRNA), si-CHOP group (transfected with CHOP siRNA), and induced by transforming growth factor-β1 (TGF-β1). The viability of the cells was measured by MTT assay, and the apoptotic rate was analyzed by flow cytometry. The protein levels of nuclear antigen Ki-67, proliferating cell nuclear antigen (PCNA), caspase-3 and cleaved caspase-3 were determined by Western blot. RESULTS:Compared with the healthy controls, the serum mRNA levels of CHOP in the patients with acute kidney injury were increased significantly (P<0.05). Transfection with CHOP siRNA significantly decreased the expression of CHOP in the renal tubular epithelial HK2 cells (P<0.05). Knock-down of CHOP expression by siRNA significantly increased the viability of renal tubular epithelial HK2 cells (P<0.05), decreased the apoptotic rate (P<0.05), increased the expression of Ki-67 and PCNA (P<0.05), and down-regulated the protein level of cleaved caspase-3 (P<0.05). CONCLUSION:The serum mRNA levels of CHOP were increased in the patients with acute kidney injury. Knock-down of CHOP expression inhibits the apoptosis of renal tubular epithelial cells by regulating the expression of proliferation-and apoptosis-related proteins.     

Inhibitory effect of oxymatrine on high glucose-induced rat renal tubular epithelial-mesenchymal transition

AIM:To investigate the inhibitory effect of oxymatrine (OM) on high glucose-induced rat renal tubular epithelial-mesenchymal transition (EMT). METHODS:The rat renal tubular epithelial NRK52E cells were cultured in vitro. The cells were divided into control group, high glucose group, high glucose+different concentrations of OM groups and high glucose+0.50 g/L OM dynamic observation group. The expression of TGF-β1, Smad7, α-SMA and E-cadherin at mRNA and protein levels was detected by real-time PCR and Western blotting. The viability of NRK52E cells was determined by MTT assay. RESULTS:(1) Compared with control group, the expression of TGF-β1 and α-SMA at mRNA and protein levels in high glucose group gradually increased, and Smad7 protein and E-cadherin mRNA and protein gradually reduced, but the mRNA expression of Smad7 gradually increased. (2) Compared with high glucose group, as increases in OM doses, the expression of TGF-β1 and α-SMA at mRNA and protein levels in high glucose+different concentrations of OM groups gradually reduced, and Smad7 protein and E-cadherin mRNA and protein gradually increased, but the mRNA expression of Smad7 had no significant change. (3) Compared with high glucose group, the expression of TGF-β1 and α-SMA at mRNA and protein levels was significantly reduced, the expression of E-cadherin at mRNA and protein levels significantly increased, and the protein expression of Smad7 significantly increased, but the mRNA expression of Smad7 had no significant change in high glucose+0.50 g/L OM dynamic observation group. CONCLUSION: In NRK52E cells, oxymatrine inhibits high glucose induced EMT by down-regulating TGF-β1 and up-regulating Smad7, thus preventing the fibrosis effect of TGF-β1/Smads signaling.     

Role of Snail in the renal tubular epithelial-mesenchymal- transition mediated by activator protein-1

AIM: To study the role of Snail in the renal tubular epithelial-myofibroblast transdifferentiation and fibronectin synthesis mediated by activator protein-1. METHODS: The cultured HK2 cells were divided into three groups: normal glucose group (NG), high glucose group (HG) and activator protein-1 (AP-1) inhibited group (AG). Concentration of fibronectin into the culture media was determined by ELISA. The activity of activator protein-1 was assessed with electrophoretic mobility shift assay (EMSA). The protein of E-cadherin and vimentin was determined by immunocytochemistry. RT-PCR was used to detect the mRNA expression of vimentin and Snail. Western blotting was used to detect the protein expression of E-cadherin.RESULTS: Secreted FN level was significantly up-regulated by the stimulation of high glucose (P<0.05), but the level significantly decreased in AP-1 inhibited group than that in high glucose group (P<0.05). AP-1 binding activity was significantly stimulated by high glucose and the inhibitor of AP-1 inhibited high glucose induced AP-1 activation in HK-2. High glucose induced Snail mRNA expression, while the level significantly decreased in AP-1 inhibited group than that in high glucose group (P<0.05). Upon the stimulation with high glucose, the expression of E-cadherin protein decreased markedly (P<0.05), while the level was higher in AP-1 inhibited group than that in high glucose group (P<0.05). Cultured with high glucose, the expression of vimentin mRNA and protein significantly increased (P<0.05), but the level significantly decreased in AP-1 inhibited group than that in high glucose group (P<0.05). CONCLUSION: High glucose induces the expression of Snail through the activation of AP-1. The expression of Snail downregulates E-cadherin expression and induces transdifferentiation of renal tubular cells characterized by vimentin expression and fibronectin synthesis.     

Mechanism of mesenteric lymph duct ligation against the renal insufficiency in hemorrhagic shock rats

AIM: To observe the effect of mesenteric lymph duct ligation on free radical and inflammatory mediator in serious hemorrhagic shock rats at different periods, and explore the mechanism of intestinal lymphatic pathway on renal insufficiency. METHODS: 78 male Wistar rats were divided into the sham group, shock group, and ligation group. The model of serious hemorrhagic shock was established in shock group, ligation group, and mesenteric lymph was blocked by ligating mesenteric lymph duct in ligation group after resuscitating. All rats were executed and kidneys were taken out for making homogenate of 10 percent to determine levels of MDA, SOD, NO, NOS, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and myeloperoxidase (MPO) at time points after shock 90 min, after transfusion and resuscitate 0 h, 1 h, 3 h, 6 h, 12 h and 24 h. The expression of inducible nitric oxide synthase (iNOS) mRNA in kindey was detected by RT-PCR. RESULTS: The contents of MDA, NO, NOS, TNF-α, IL-6, MPO and iNOS expressions in renal homogenate of shock group were increased after transfusion and resuscitation, and were higher at 6 h and 12 h, and was significantly higher than that in sham group. The acvitity of SOD was significantly lower than that in sham group (P<0.01, P<0.05). The contents of MDA, NO, NOS, TNF-α, IL-6, MPO and iNOS expression in renal homogenate of ligation group after transfusion and resuscitation 6 h, 12 h and 24 h were significantly lower than those in shock group at same points, and the SOD activity was higher (P<0.01, P<0.05). CONCLUSION: The results demonstrate that the ligation of mesenteric lymph duct can antagonise the development of renal failure in serious hemorrhagic shock rats, and its mechanism might relate to reduce the PMN sequestration, decrease the levels of TNF-α and IL-6, inhibit NO production and expression of iNOS mRNA, suppress the release of free radical and consumption of SOD.     

Effect of autophagy on necroptosis of renal tubular epithelial cells in subtotal nephrectomy rats

AIM: To explore whether autophagy is involved in the excessive death of renal tubular epithelial cells in subtotal nephrectomy(SNx) rats and the relationship between autophagy and necroptosis in the kidney of SNx rats. METHODS: Male Sprague-Dawley rats were randomly assigned to control group(n=6) and SNx group(n=42). The rats in SNx group were subjected to SNx. Sham surgery was performed in the rats in control group. The rats in SNx group were divided into subgroups at 0, 4, 8 and 12 weeks(n=6) and the other rats in SNx group were divided into SNx+vehicle group, SNx+necrostatin-1(Nec-1) group and SNx+3-methyladenine(3-MA) group. The expression of RIP1, RIP3, LC3 and beclin-1 at mRNA and protein levels was measured at 0, 4, 8 and 12 weeks by qPCR and immunohistochemistry. The effects of Nec-1 or 3-MA on the protein expression of LC3-I, LC3-II and beclin-1, and production of reactive oxygen species(ROS) in the rat kidney were determined by Western blot and DCFH-DA staining. The death of renal tubular epithelial cells in the SNx rats was observed by TUNEL staining and electron microscopy. Finally, the effects of Nec-1 and 3-MA on blood urea nitrogen(BUN), serum creatinine(SCr) and the pathological changes of the renal tissues were analyzed. RESULTS: The highest mRNA and protein levels of RIP1, RIP3, LC3 and beclin-1 appeared at the 8th week after SNx(P<0.01). Compared with the rats in SNx+vehicle group, the protein over-expression of LC3-II/I and beclin-1, renal tubular epithelial cells with typical morphological features of necroptotic cell death and TUNEL-positive renal tubular cells were decreased in the SNx rats treated with Nec-1 and 3-MA(P<0.01), but 3-MA did not reduce the increased concentration of ROS. In addition, treatment with Nec-1 and 3-MA obviously reduced BUN, SCr(P<0.05), glomerulosclerosis index and tubulointerstitial injury score(P<0.01). CONCLUSION: Autophagy participates in the excessive death of renal tubular epithelial cells in SNx rats. Inhibition of autograph prevents necroptotic cell death of renal tubular cells, and alleviates chronic renal injury in SNx rats.     

Effects of ghrelin on brain edema and aquaporin 4 expression after cerebral ischemia/reperfusion in rats

AIM: To explore the effects of ghrelin on the brain edema, the permeability of blood-brain barrier (BBB) and the expression of aquaporin 4 (AQP4) after cerebral ischemia/reperfusion in rats. METHODS: Adult male Sprague-Dawley rats were randomly divided into sham operation group, middle cerebral artery occlusion (MCAO) group and ghrelin treatment group. The MCAO model was made with nylon thread for 2 h of occlusion following 22 h of reperfusion. Ghrelin at a dose of 10 nmol/kg was injected via femoral vein at the beginning of reperfusion. The cerebral infarct volume was measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Brain functional deficits were evaluated by determining the neurological scores. The changes of brain swelling and water content were analyzed through volume calculation and dry/wet weight measurement. The permeability of BBB was detected by collecting extravascular Evans blue (EB) in the brain cortex. The changes of AQP4 expression were assessed by the methods of immunohistochemistry and Western blotting. RESULTS: Compared with MCAO group, the rats in ghrelin treatment group had smaller brain infarct volume, lower EB exudation content and neurological scores. The percentage of brain swelling, water content and AQP4 expression were lower in ghrelin treatment group than those in MCAO group. CONCLUSION: Ghrelin reduces the injury of cerebral ischemia/reperfusion, and lightens the brain edema and BBB damage in rats. Ghrelin also inhibits the expression of AQP4 in brain tissue.     

Effect of Yiqi Huayu Huatan decoction on expression of KLF15, HMGB1, NF-κB and its downstream inflammatory factors in rats with UUO-induced renal interstitial fibrosis

AIM: To observe the effect of Yiqi Huayu Huatan decoction (YHHD) on unilaterral ureteral obstruction (UUO)-induced renal interstitial fibrosis in rats, and to investigate the possible mechanism. METHODS: Female SD rats (n=48) were randomly divided into sham group, model group, telmisartan group, and low-, middle-and high-dose YHHD groups, with 8 rats in each group. The UUO model rats was established by ligating left ureter. The rats in sham group and model group were treated with equal volume of normal saline, others were treated with the corresponding drugs daily. After 12 weeks, the rats were sacrificed. The serum samples were collected for determining the concentrations of cystatin C (Cys-C) and uric acid (UA). The morphological changes of the renal tissue were observed by PAS staining. The collagen fiber was observed by Masson staining. The mRNA expression of Krüppel-like factor 15 (KLF15), high-mo-bility group box protein 1 (HMGB1), nuclear factor-κB (NF-κB), IκB, monocyte chemotactic protein-1 (MCP-1), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), fibronectin (FN), collagen type I (Col I) and Col-Ⅳ was detected by real-time PCR. The protein expression of KLF15, HMGB1 and NF-κB was detected by Western blot. The protein expression of MCP-1 was determined by the method of immunohistochemistry. RESULTS: Compared with sham group, the deposition rate of collagen fibers and the concentration of Cys-C in model group were significantly increased (P<0.05), the mRNA and protein expression of KLF15 was significantly down-regulated (P<0.05), while the mRNA expression of HMGB1, NF-κB, IκB, MCP-1, IL-1β, TNF-α, FN, Col I and Col Ⅳ and the protein expression of HMGB1, NF-κB and MCP-1 were significantly up-regulated (P<0.05). Compared with model group, the deposition rates of collagen fibers in middle-and high-dose YHHD groups and telmisartan group were significantly decreased (P<0.05), with down-regulated protein expression of HMGB1 and NF-κB and mRNA expression of IL-1β and TNF-α (P<0.05). The protein expression of KLF15 was significantly up-regulated in high-dose YHHD group and telmisartan group (P<0.05), while the protein expression of MCP-1 and the mRNA expression of FN were significantly down-regulated (P<0.05). The mRNA expression of KLF15 was significantly up-regulated in high-dose YHHD group (P<0.05), while the mRNA expression of MCP-1, Col I and Col IV was significantly down-regulated (P<0.05). The mRNA expression of NF-κB and IκB was significantly down-regulated and the concentration of Cys-C was significantly decreased in each dose of YHHD groups and telmisartan group (P<0.05). No significant difference of UA level among the groups was observed. CONCLUSION: YHHD alleviates renal interstitial fibrosis in a dose-dependent manner, and YHHD at high dose shows the most obvious effect. The mechanism may be associated with the up-regulation of KLF15 and the down-regulation of HMGB1, NF-κB and its downstream inflammation-related factors in the renal tissue.     

High glucose induces down-regulation of BMP-7 expression in renal tubular epithelial cells through p38 MAPK pathway

AIM: To observe the BMP-7 expression in primary renal tubular epithelial cells cultured with high glucose and to investigate the role of p38MAPK signaling pathway.METHODS: The primary renal tubular epithelial cells were randomly treated with normal glucose, high glucose, co-incubation of high glucose with specific p38MAPK inhibitor SB202190 or D-mannitol for 72 h. The protein expression of BMP-7 and fibronectin (FN) in all the cells was assessed by the method of immunocytochemistry. The protein expression of p38MAPK and p-p38MAPK was determined by Western blotting. The mRNA expression of BMP-7 and FN was detected by RT-PCR.RESULTS: In normal glucose group, BMP-7 was highly expressed in the cytoplasm of tubular epithelial cells, and only small amounts of p38MAPK and FN, but not p-p38MAPK, were observed. High glucose was able to activate p38MAPK, and therefore the protein of p-p38MAPK increased remarkably in high glucose-treated cells. High glucose also enhanced FN production. Meanwhile, the expression of BMP-7 decreased. Co-incubation of high glucose with SB202190 for 72 h reduced the activity of p38MAPK by 80% and the FN expression was also decreased, while the BMP-7 expression significantly increased. No significant difference of the BMP-7 or FN expression between control group and D-mannitol group was observed.CONCLUSION: The expression of BMP-7 at mRNA and protein levels in renal tubular epithelial cells is decreased under the condition of high-glucose cultivation. Suppression of p38MAPK signaling pathway stimulates endogenous BMP-7 expression, indicating that p38MAPK pathway may be involved in the down-regulation of BMP-7 in renal tubular epithelial cells by high glucose.     

Effects of PKC,VDR and their interaction on expression of NaDC1 in rat renal tubular epithelial NRE-52E cells

AIM: To investigate effects of protein kinase C (PKC), vitamin D receptor (VDR) and their interaction on expression of Na⁺/dicarboxylate contransporter 1 (NaDC1) in rat renal tubular epithelial NRE-52E cells. METHODS: Rat renal tubular epithelial cell line NRE-52E was cultured in vitro. PKC agonist and inhibitor were used to interfere with NRE-52E cells. VDR over-expression and shRNA vectors were used to transfect into NRE-52E cells. The protein expression of PKC, VDR and NaDC1 in the cells was determined by Western blot. RESULTS: The NRK-52E cells with stable VDR over-expression and stable VDR interference were successfully set up. Compared with control group, the protein expression of VDR and NaDC1 in PKC agonist group and VDR over-expression group was increased significantly (P<0.01), and that in VDR interference combined with PKC agonist group and VDR over-expression combined with PKC inhibitor group was between VDR interference group and VDR over-expression group. CONCLUSION: In rat renal tubular epithelial cell line NRE-52E, enhanced PKC activity induces protein expression of VDR, while decrease in PKC activity inhibits the protein expression of NaDC1. There is a significantly positive correlation between VDR and regulation of PKC and NaDC1 protein expression. When PKC and VDR interact with each other, high activity of PKC and over-expression of VDR are the main factors to promote or maintain NaDC1 protein expression in the NRE-52E cells.     

Protective effect of delayed ischemic preconditioning on renal ischemia/reperfusion injury via induction of hypoxia inducible factor

AIM: To investigate the effects of delayed ischemic preconditioning on renal ischemia-reperfusion injury in mice and to study the role of hypoxia inducible factor 1α(HIF-1α). METHODS: Male C57/BL6N mice were randomly divided into 3 groups: sham operation group(sham), ischemia/reperfusion group(IR) and ischemic preconditioning group(IPC). Thirty-minute ischemia was induced by clamping renal bilateral pedicles followed by reperfusion in IR group. Fifteen-minute pre-ischemia was performed 4 days before IR in IPC group. Serum creatinine(Scr), blood urea nitrogen(BUN), kidney morphology and apoptosis were observed at different time points following reperfusion. The expression of HIF-1α in the renal tissues was evaluated by the methods of immunohistochemistry and Western blotting analysis. The mRNA expression of vascular endothelial growth factor(VEGF) and glucose transporter-1(Glut-1) was detected by real-time quantitative RT-PCR.RESULTS: Compared with IR group at 24 h following reperfusion, acute tubulointerstitial injury was significantly relieved in IPC group. The levels of Scr and BUN, and apoptosis of tubular epithelial cells were also decreased in IPC group. Nuclear expression of HIF-1α was higher in IPC group than that in IR group. The mRNA expression of VEGF and Glut-1, the target genes of HIF-1, was also increased significantly in IPC group. CONCLUSION: Delayed ischemic preconditioning attenuates both morphologic and functional injuries induced by renal ischemia/reperfusion. This protective effect may be related to the increased expression of hypoxia inducible factor.     

Effect of tumor suppressor phosphatase and tensin homology deleted in chromosome 10 on renal interstitial fibrosis in IgA nephropathy

AIM: To explore the potential correlation between the expression of phosphatase and tensin homology deleted on chromosome 10(PTEN) and RIF in IgA nephropathy. METHODS: Forty-seven patients diagnosed as primary IgA nephropathy by renal histology were involved. 10 specimens from normal renal tissue of renal carcinoma served as control group. Tubulointerstitial lesion (TIL) was classified by using Katafuchi scale, including no TIL (group I), mild TIL (group II), moderate TIL (group III), severe TIL (group IV). The expressions of PTEN, TGF-β1, α-SMA and ColⅢ in renal tissue were detected by immunohistochemistry. PTEN mRNA was detected by in situ hybridization. RESULTS: Renal tissues from renal biopsy showed abundant expressions of PTEN and PTEN mRNA in endochylema of renal tubular epithelial cells, and negligible expression in glomeruli. With the progress of TIF in IgA nephropathy, the expressions of PTEN and PTEN mRNA decreased gradually (P<0.05). In contrast, the expressions of TGF-β1, α-SMA and ColⅢ increased significantly (P<0.05). The expressions of PTEN and PTEN mRNA in renal tissues were positively with eGFR and urine osmotic pressure (P<0.01), negatively correlated with the expressions of TGF-β1, α-SMA, ColⅢ, urinary protein excretion for 24 h, the rate of sclerosis glomeruli and the scores of vascular lesion (P<0.01). CONCLUSION: These results suggest the loss of PTEN expression in RIF of IgA nephropathy. Moreover, TGF-β signaling induces epithelial to mesenchymal transition and extracellular matrix accumulation possibly through a mechanism dependent on the downregulation of PTEN.     

Effects of atorvastatin on iopromide-induced apoptosis of renal tubular epithelial cells in diabetic rats

AIM：To investigate the protective effect of atorvastatin (ATO) against contrast medium (CM)-induced apoptosis of renal tubular epithelial cells in diabetic rats. METHODS：Streptozocin-induced diabetic Wistar rats were fed for 8 weeks and then randomly divided into 5 groups: diabetes mellitus (DM) group, DM with iopromide (a kind of CM) treatment group (DM+CM group), and groups of DM rats treated with ATO at 5 mg·kg-1·d-1 (ATO1 group), 10 mg·kg-1·d-1 (ATO2 group) and 30 mg·kg-1·d-1 (ATO3 group) before iopromide injection. Healthy Wistar rats served as normal controls (N group). Urine creatinine (UCr) and 24-hour urinary albumin (24 h-UAlb) were determined 24 h after iopromide injection. Serum creatinine (SCr) and blood urea nitrogen (BUN) were detected 48 h after iopromide injection, and then creatinine clearance (CCr) and 24-hour urinary albumin excretion rate (24 h-UAER) were calculated. The rats were sacrificed and both kidneys were removed 48 h after iopromide injection. For the left kidney, the morphology by HE staining, the renal tubular apoptosis by TUNEL and the expression of Bax and Bcl-2 by immunohistochemistry were detected. For the right kidney, the expression of Bax and Bcl-2 was measured by Western blotting. RESULTS：Compared with N and DM groups, the levels of SCr, BUN and 24 h-UAER, as well as the expression of Bax in the renal medulla were higher, the levels of Ccr and Bcl-2 expression in the renal medulla were lower and TUNEL-positive cells were more in DM+CM group. Compared with DM+CM group, ATO attenuated these changes, especially in ATO3 group. CONCLUSION: Iopromide could cause renal tubular apoptosis. Early application of ATO could dose-dependently attenuate the development of contrast-induced acute kidney injury, partly due to suppression of iopromide-induced renal tubular apoptosis.