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Objective To observe the effects of 7,8-dihydroxyflavone (7,8-DHF) on hypoxia induced endoplasmic reticulum stress (ERS) in human proximal tubular epithelial cells (HK-2).Methods The mRNA level of ERS associated biomarkers was evaluated by RT-PCR assay in cell hypoxia damaged model.And HK-2 cells were pretreated with different concentrations of 7,8-DHF through CCK-8 assay;meanwhile CCAAT/enhancer-binding protein homologous protein (CHOP),Cyr61,Akt and p-Akt were determined by western blotting assay.Moreover,HK-2 cells were pretreated by LY294002,a kind of PI3K/Akt inhibitor,to inhibit the PI3K/Akt signaling,and its effects on protein level induced by 7,8-DHF was detected.HK-2 cells was then over-expressed Cyr61 and exposed to hypoxia Apoptosis rate and CHOP expression were determined.Results Compared to hypoxia group (P ＜ 0.01),Hypoxia for 12h was effective in inducing ERS (P ＜ 0.01),while pretreatment with 7,8-DHF (100 μmol/L) increased cell proliferation significantly.The protein expressions of Cyr61 and p-Akt in H+7,8-DHF group were higher,but the level of CHOP was decreased (P ＜ 0.05).With LY294002 pretreated,the expression of Cyr61,p-Akt was down-regulated (all P ＜ 0.05) while the expression of CHOP was up-regulated (P ＜ 0.05).In comparison to empty plasmid group,when cells were transfected with over-expression of Cyr61 plasmid and exposed to hypoxia,the number of apoptotic tubular cells was decreased (P ＜ 0.01).And over-expression of Cyr61 significantly reducedCHOP expression compared with the empty plasmid group (P ＜ 0.01).Conclusion Pretreatment of 7,8-DHF could protect cells from hypoxia injury and inhibit ERS,which may involve the Akt-Cyr61 signaling pathway.
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Objective To detect the effect and mechanism of Cyr61 on the apoptosis of renal tissue caused by early stage of ischemic acute kidney injury (AKI). Methods 30 SD rats were randomized into 5 groups, including control group, AKI group, AKI+bicarbonate group, AKI+blank virus group, and AKI+over?expression Cyr61 virus group. After animal models were created for 2h, serum and renal tissue were collected from sacrificed animals. Expression level of TNF?α was determined by ELISA. HE staining was used to observe the histologic changes of renal tissues. The levels of NF?κB p65 and TNFR1 were measured by immunohistochemical method. RT?PCR and Western blotting assay were adopted to detect the mRNA and protein expression levels of NF?κB p65, TNFR1 and Caspase3. Results Compared with control group, AKI group, AKI+bicarbonate group, AKI+blank virus group, AKI+over?expression Cyr61 virus group had obvious kidney injury. The levels of TNF?α, the mRNA and protein expression levels of NF?κB p65, TNFR1 and caspase3 were markedly up?regulated. Over?expression of Cyr61 significantly attenuated the degree of pathological injury, numbers of apoptotic renal tubular epithelial cells and increased the degree of Scr. Although compared with other groups, the level of TNF?α in kidney tissue had no difference, there was obvious decreased protein level of NF?κB p65, while the increase of TNFR1 and Caspase3 protein was moderate. Conclusions During the early stage of AKI, over expression of Cyr61 could inhibit apoptosis, which may be related to the suppression of TNFR1 transcriptional expression and interference of TNF?αpathway. Its underlying mechanism therefore deserves further research.
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Objective To establish the experimental animal model of acute tubular necrosis (ATN) in rats induced by caulis aristolochiae manshuriensis (CAM) containting aristolochic acid (AA) and compare the interventional effects among ligustrazine, prednisone and benazepril. Methods Male SD rats were divided randomly into six groups, 12 rats in each group. Control group, model group, prednisone group, benazepril group, ligustrazineⅠgroup and ligustrazineⅡgroup were given respectively by gavage with 3 ml/d distilled water,5 g?kg-1?d-1 CAM decoction (CAM 2 g/ml, AA 0.54 mg/ml, AA-Ⅰ0.46 mg/ml) for 60 days, then 3 ml/d distilled water, 10 g?g-1?d-1 CAM decoction for 30 days. Two hours after CAM gavage, control group and model group were given with normal saline. Prednisone group, benazepril group, ligustrazine group and ligustrazineⅡgroup were given with prednisone 5 mg?kg-1?d-1, benazepril 1.7 mg?kg-1?d-1, ligustrazine 50 mg?kg-1?d-1, ligustrazine 150 mg?kg-1?d-1 respectively by gavage for 90 days. Histopathology of kidney tissue was examined after 90 days. Results The renal tissue of control group was normal. Light microscopy of model group revealed patchy vacuolar changes of cells from proximal convoluted tubular epithelium, disorder and loss of brush border, exfoliated epithelial cells in the lumina, exposure of areas of denuded and rupture and thickness and atrophy of tubular basement membrane (TBM), edema and infiltration of inflammatory cells in the interstitium, focal segmental proliferation of glomerular mesangial cells and increase of mesangial matrix, part thickness of interlobular arterial walls. The above abnormalities of other four groups were significantly attenuated compared to model group. Electron microscopy of model group revealed patchy vacuolar changes and fatty degeneration of cells from proximal convoluted tubular epithelium, swelling of mitonchondria, reduce of organelle, karyorrhexis, apoptosis, infiltration of inflammatory cells (phagocytes and lymphocytes) in the interstitium and infiltration of lymphocytes in the epithelium, thickness of interlobular arterial walls, stenosis of lumina. The above abnormalities of electron microscopy in other four groups were remarkably improved compared to model group as well, especially in ligustrazine II group and prednisone group. Conclusions Pathological change of ATN is confirmed in kidney tissue and the rat ATN model induced of AA is successfully established. Benazepril, prednisone and ligustrazine can attenuate the toxic effects by AA. Prednisone and ligustrazine have a better efficacy.
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This paper is to report the pathological changes in canine renal tissues after severe steam inhalation injuries. The specimens from 84 male mongrel dogs are studied with a light microscope, and 30 tissue samples of the 84 with an electron microscope. The morphological changes of glomeruli are characterized by, hypertrophy and/or hyperplasia of the glomerular cells, the former manifested as cell enlargement, increased amount of cytoplasm and rich in organelles; retrogressive changes of the glomerular cells in varying degrees as evidenced by intra-cellular edema. The renal tubules show varying degrees of degeneration, necrosis, and casts formation. Tubular necrosis affects more frequently the proximal convoluted tubules. The etiological factors of it are briefly discussed.