Experimental study on treating rat focal segmental glomerulosclerosis with Decoction of Bu-Shen-Huo-Xue-Xie-Zhuo

AIM:To observe the effects of Decoction of Bu-Shen-Huo-Xue-Xie-Zhuo (BSHXXZ) on focal segmental glomerulosclerosis (FSGS) in rats. METHODS:Unilateral nephrectomy was adopted firstly, one week later adrimycin was intravenously adminstered to 20 rats twice in a 23-day period to establish an advanced focal segmental glomerulosclerosis model in the rat. Changes in urine protein, blood chemistry, and histology of the kidney were investigated for 110 days after unilateral nephrectomy. RESULTS:The BSHXXZ decoction reduced edema, proteinuria, hyperlipidemia, azotemia and ascites, and increased albumin in blood. Light microscopic, electron microscopic, immunohistochemical and polarizing microscopic examination all showed that the pathologic changes in the treatment group were less than that of the model group. CONCLUSION:Decoction of BSHXXZ could markedly improve renal function and delay the progression of glomerulosclerosis and renal interstitial fibrosis.     

p38MAPK expression and apoptosis in the rat unilateral ureteral obstruction model

AIM: To investigate the expression of p38 mitogen-activated protein kinase (p38MAPK) in the kidney after unilateral ureteral obstruction (UUO) in rats and the functional role of it on apoptosis and fibrosis.METHODS: Eighteen Wistar rats underwent UUO were killed at 3, 7, 14 days. Additional 7 rats were sham operated. Histological changes were observed by HE and Masson staining. Immunohistochemistry study was performed on renal tissue for proliferating cell nuclear antigen (PCNA). Apoptotic cells were determined by terminal deoxynucleotidyl transferase- mediated dUTP nick end labeling (TUNEL) and the electrophoresis analysis of genomic DNA. Western blotting of cysteinyl aspartate specific proteinase-3 (caspase-3), p38MAPK and p-p38MAPK were measured.RESULTS: UUO induced a significant increase in renal tubular and interstitial cell apoptosis, immunohistochemistry of PCNA and Western blotting of caspase-3, p-p38MAPK as well as severe morphology changes. However, there was no significant difference between UUO and the control in Western blotting of p38MAPK.CONCLUSION: An in vivo model of renal fibrosis after UUO demonstrates that activated or phosphorylated p38MAPK plays a role in apoptosis of renal tubulointerstitial cells.     

The renoprotective role of all-trans retinoic acid in retarding rat glomerulosclerosis with 5/6 nephrectomy

AIM: To explore if all trans retinoic acid (atRA) retards glomerulosclerosis of rats with 5/6 nephrectomy. METHODS: Wistar male rats were operated by subtotal nephrectomy and were randomly divided into A1 (5 mg·kg-1·d-1 atRA), A2 (10 mg·kg-1·d-1 atRA), A3 (20 mg·kg-1·d-1 atRA) and NX (vehicle) groups. Each group included 8 rats. 8 health rats were assigned as sham-operation group (sham group). Animals were sacrificed 10 weeks after treatment. The concentrations of plasma atRA were measured by reversed phase high performance liquid chromatography (RP-HPLC). Glomerulosclerosis was evaluated by glomerulosclerosis index system. The expression of transforming growth factor-beta 1 (TGFβ1) was measured by renal immunohistochemical staining and Western blotting. RESULTS: The concentrations of atRA in atRA groups were much higher than that in NX and sham groups. Compared to NX, the remnant kidney sclerosis was ameliorated significantly in A1, A2 and A3 groups. The expressions of TGFβ1 decreased parallelized to the levels of glomerulosclerosis. CONCLUSION: atRA has a beneficial effect on retarding the progression of renal fibrosis in the 5/6 nephrectomic rats, possibly through downregulating the glomerular TGFβ1 expression.     

C-reactive protein induces apoptosis in human renal tubular epithelial cells

ATM: To explore whether the C-reactive protein (CRP) level in microinflammation state induces the apoptosis of renal tubular epithelial cells. METHODS: HK-2 cells were stimulated with recombinant human CRP. Annexin-FITC-PI staining and flow cytometry were used to detect the percentage of apoptotic cells. Morphology observation of apoptosis was assessed by Hoechst 33258 staining. Caspase-3 activity was measured by a colorimetric assay. The expression of apoptotic gene bax and anti-apoptotic gene bcl-2 at mRNA levels was determined by real-time PCR. RESULTS: CRP induced apoptosis of HK-2 cells in a time- and dose-dependent manner. The maximal apoptotic effect of CRP concentration was 10 mg/L CRP at concentration of 20 mg/L. CRP treatment was associated with the characteristic morphological features of apoptosis such as condensation, fragmentation or margination of nuclear chromatin. CRP exposure increased caspase-3 activity, up-regulated the mRNA expression of Bax and down-regulated the mRNA expression of Bcl-2. CONCLUSION: Slightly increased CRP level has the potential to induce apoptosis of renal tubular cells.     

Berberine promotes anti-proliferative effects of doxorubicin in T24 bladder cancer cells by enhancing apoptosis

AIM: To observe the effect of berberine (Ber) on doxorubicin (DOX)-induced apoptosis in bladder cancer T24 cells. METHODS: The cells were exposed to DOX in the presence or absence of different concentrations of Ber. The viability of the cells was determined by CCK-8 assay. The apoptosis was measured by Hoechst 33258 staining and the protein levels of cleaved caspase-3, cleaved caspase-9, Bcl-2 and Bax were detected by Western blotting.RESULTS: Ber enhanced the inhibitory effect of DOX on the viability of T24 cells and promoted DOX-induced apoptosis in T24 cells. DOX increased the protein levels of cleaved caspase-3, cleaved caspase-9 and Bax, all of which were enhanced by treatment with Ber. In contrast, Ber exposure further decreased the expression of Bcl-2 in DOX-treated T24 cells.CONCLUSION: Ber enhances the anti-proliferative effects of DOX through promoting apoptosis in bladder cancer cells.     

Effect of HIPK2 gene on viability,apoptosis and JAK2/STAT3 signaling pathway in NRK-52E renal tubular epithelial cells induced by hypoxia and reoxygenation

AIM: To investigate the effect of homeodomain-interacting protein kinase 2 (HIPK2) on the viabi-lity, apoptosis and JAK2/STAT3 signaling pathway in NRK-52E renal tubular epithelial cells induced by hypoxia and reoxygenation (H/R). METHODS: HIPK2 small interfering RNA (siRNA) was transfected into NRK-52E cells by Lipofectamine^TM 2000, and normal control group (control group) and negative control group (HIPK2-NC group) were set up. After H/R, the cell viability was measured by CCK-8 assay, the apoptotic rate and Ca²⁺ fluorescence intensity were analyzed by flow cytometry, and the protein levels of Ki67, cleaved caspase-3, caspase-12, Bcl-2, Bax, p-JAK2 and p-STAT3 were determined by Western blot. RESULTS: Compared with control group, the protein expression of HIPK2 in the NRK-52E cells was significantly decreased after transfection with HIPK2 siRNA (P<0.05). Compared with control group, the cell viability and the protein expression of Ki67 and Bcl-2 in H/R group were also significantly decreased, and the apoptotic rate, the Ca²⁺ fluorescence intensity and the protein levels of cleaved caspase-3, caspase-12, Bax, p-JAK2 and p-STAT3 were significantly increased (P<0.05). Compared with H/R group, the cell viability and the protein expression of Ki67 and Bcl-2 in HIPK2-siRNA+H/R group were significantly increased, while the apoptotic rate, the Ca²⁺ fluorescence intensity and the protein levels of cleaved caspase-3, caspase-12, Bax, p-JAK2 and p-STAT3 were significantly decreased (P<0.05). CONCLUSION: Inhibition of HIPK2 gene expression promotes H/R-induced growth of NRK-52E renal tubular epithelial cells, and reduces the apoptosis. The mechanism is related to down-regulating the JAK2/STAT3 signaling pathway.     

Effects of tetrahydroxystilbene-2-O-β-D-glucoside on apoptosis and expression of bcl-2/bax/caspase-3 in HUVECs treated with homocysteine

AIM：To explore the effects of tetrahydroxystilbene-2-O-β-D-glucoside (TSG) from Polygonum multiflorum on the apoptosis and the mRNA expression of bcl-2, bax and caspase-3 in human umbilical vein endothelial cells (HUVECs) treated with homocysteine (Hcy). METHODS：Cultured HUVECs were treated with Hcy (3 mmol/L) to establish a Hcy-damaged model. HUVECs in TSG treated groups were pre-incubated with TSG at concentrations of 1 μmol/L and 10 μmol/L for 2 h before treated with Hcy. Cell nuclear damage was detected by Hoechst 33342 staining. Cell apoptosis was determined by flow cytometry. The mRNA expression of bcl-2, bax and caspase-3 was measured by real-time fluorescence quantitative RT-PCR. RESULTS： After treatment with Hcy at concentration of 3 mmol/L, the nuclear damage and apoptotic rate of HUVECs were higher than that in normal group. The expression of bcl-2 was lower, and the expression of Bax and caspase-3 was higher than that in normal group. On the other hand, pre-incubation with TSG at concentrations of 1 μmol/L and 10 μmol/L decreased the nuclear damage and cell apoptosis, increased the expression of bcl-2, and decreased the expression of bax and caspase-3 as compared with the cells only treated with Hcy. CONCLUSION：TSG reduces the apoptosis of HUVECs induced by Hcy, and the mechanism might be associated with regulating the expression of bcl-2, bax and caspase-3.     

Inhibitory effect of poncirin on viability of gastric cancer cells and underlying mechanism

AIM: To explore the effect of poncirin on the growth of AGS gastric cancer cells and the underlying mechanism.METHODS: The effect of poncirin on AGS cell viability was measure by MTT assay. The cell cycle distribution and cell apoptosis were analyzed by flow cytometry. Nuclear staining with DAPI was used to reflect the morphological change of the AGS cells treated with poncirin. The protein levels of extrinsic apoptosis pathway-related proteins such as FasL, caspase-8, caspase-3 and PARP, and mitochondria-mediated intrinsic apoptosis pathway-associated proteins such as Bak, Bcl-xL, Bax and caspase-9 were determined by Western blot.RESULTS: Poncirin inhibited the viability of AGS gastric cancer cells in a time-and concentration-dependent manner (P<0.05). Poncirin induced accumulation of G₁ DNA content and significantly increased total apoptosis in the AGS cells. Nuclear staining showed a dose-dependent increase in the number of apoptotic cells after treated with poncirin.The protein level of FasL was upregulated in a dose-dependent manner by treatment with poncirin. Poncirin significantly activated caspase-8 and caspase-3. Moreover, poncirin significantly induced the cleavage of PARP in a dose-dependent manner (P<0.05). In addition, the protein levels of Bcl-xL, Bax and Bak were unchanged after treated with different doses of poncirin. Furthermore, caspase-9 was not activated by poncirin treatment in the AGS cells.CONCLUSION: Poncirin has the anti-cancer effect via extrinsic apoptosis pathway to inhibit the growth of AGS gastric cancer cells, possibly making it a therapeutic agent for human gastric cancer treatment.     

Nisin induces apoptosis of human osteosarcoma MG63 cells via oxidative stress

AIM To investigate the effect of nisin on apoptosis of human osteosarcoma MG63 cells and its related oxidative stress mechanism. METHODS The MG63 cells were cultured in the medium containing different concentrations of nisin with or without antioxidant N-acetyl-L-cysteine （NAC）. The cell viability was measured by CCK-8 assay. Apoptosis was analyzed by flow cytometry with annexin-V/PI staining. The production of intracellular reactive oxygen species （ROS） was detected by redox-sensitive dye 2',7'-dichlorofluorescein diacetate （DCFH-DA）. The 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl benzimidazolyl carbocyanine iodide （JC-1） was used to detect the changes of mitochondrial membrane potential （MMP）. The protein levels of apoptosis-associated molecules Bax, Bcl-2 and cleaved caspase-3 were determined by Western blot. RESULTS Nisin decreased the viability of MG63 cells and promoted the apoptosis in a dose-dependent manner. It also up-regulated the protein level of cleaved caspase-3, increased the protein expression ratio of Bax/Bcl-2, triggered a large amount of intracellular ROS generation and reduced the MMP （P<0.05）. Moreover, antioxidant NAC significantly inhibited nisin-induced apoptosis of MG63 cells, down-regulated the protein level of cleaved caspase-3, decreased Bax/Bcl-2 ratio, reduced intracellular ROS level, and restored the MMP （P<0.05）. CONCLUSION Nisin may promote oxidative stress in human osteosarcoma cells, activate mitochondrial apoptosis pathway, and eventually induce apoptosis.     

Effects of phycocyanin on apoptosis of human laryngeal cancer HEP-2 cells

AIM: To investigate the effect of phycocyanin on the apoptosis of human laryngeal cancer HEP-2 cells and to explore the inhibitory mechanism of phycocyanin to tumor. METHODS: Highly purified phycocyanin was extracted from spirulina. The effects of phycocyanin at different concentrations on the growth of human laryngeal cancer HEP-2 cells were detected by MTT assay. In addition, the cell structures were observed under electron microscope. The cell apoptosis was analyzed by flow cytometry. The production of reactive oxygen species (ROS) was measured by flow cytometry. Enzymatic activities of caspase-3, -8 and -9 were measured by chemical colorimatry. The expression of Bax, Bcl-2, Fas, P53, caspase-3 and caspase-9 at mRNA and protein levels was determined by RT-PCR and Western blot. RESULTS: MTT test confirmed that phycocyanin inhibited the cell activity of HEP-2 cells with time and dose dependent manners. The result of electron microscope observation and flow cytometry indicated that phycocyanin induced the apoptosis of HEP-2 cells. The intracellular content of ROS was increased. The activities of caspase-3, -8 and -9 were increased. RT-PCR showed that the mRNA expression of Bax, Fas, P53, caspase-3, caspase-9 was increased and Bcl-2 was decreased. The results of Western blot were consistent with the results of RT-PCR. CONCLUSION: Phycocyanin might induce apoptosis of HEP-2 cells by down-regulating Bcl-2, up-regulating Bax, Fas and P53, and the transduction of apoptotic signals in the human laryngeal cancer cells.     

In vitro enhancement of radiation-induced apoptosis in human hepatoma cell line HepG2 by a selective inhibitor of cyclooxygenase-2 enzyme NS-398

AIM:To investigate the possible role of NS-398, a selective inhibitor of cyclooxygenase-2 enzyme, in radiation-induced apoptosis of human hepatoma cell line HepG2 in vitro. METHODS:Hepatoma cell line HepG2 was treated with various concentrations (25, 50, 100, 200 μmol/L) of NS-398 before MTT assay was used to evaluate the cytotoxicity of NS-398. Transmission electron microscopy (TEM) was used to observe the changes of apoptosis in morphology. FCM was performed to quantify the apoptotic percentage. Real-time PCR was used to detect the expression of bcl-2, bax and caspase-3 mRNA, Western blotting was used to measure the expression of Bcl-2 and bax protein, and colorimetric method was provided to analyze the change of caspase-3 activity. RESULTS:The cytotoxicity of NS-398 increased in time-dependent and dose-dependent manners. NS-398 significantly enhanced radiation-induced apoptosis (P<0.01), increased the expression of bax mRNA, Bax protein, caspase-3 mRNA and enhanced caspase-3 activity, whereas no significant change in Bcl-2 expression was found (P>0.05). CONCLUSION:NS-398 enhances radiation-induced apoptosis in hepatoma cell line HepG2. The mechanism may be associated with the up-regulation of the expression of Bax, caspase-3 and enhancement of the activity of caspase-3, which ultimately induce apoptosis in HepG2.     

Effect of ixazomib on apoptosis and NF-κB signaling pathway in pancreatic cancer cells

AIM:To investigate the effects of ixazomib on the apoptosis and NF-κB signaling pathway in pancreatic cancer cells. METHODS:Human pancreatic cancer cell lines CFPAC-1 and PANC-1 were cultured, and the cells were treated with ixazomib at 0, 10, 20, 30 and 40 nmol/L for 12, 18, 24 and 48 h. The expression of NF-κB p65, IκB kinase (IKK), Bax and caspase-3 in the cells at mRNA and protein levels was determined by RT-qPCR and Western blot. The cell viability was measured by CCK-8 assay. The apoptosis was analyzed by flow cytometry. RESULTS:Treatment with ixazomib at 10~40 nmol/L inhibited the viability of PANC-1 cells and CFPAC-1 cells, and the inhibitory rate was increased significantly with the increases in the concentration and time (P<0.05). Compared with the control cells, treatment with ixazomib significantly increased the apoptotic rates of PANC-1 cells and CFPAC-1 cells in a dose- dependent manner (P<0.05), and significantly decreased the mRNA expression levels of NF-κB p65 and IKK in the PANC-1 cells and CFPAC-1 cells (P<0.05), while the mRNA expression levels of apoptotic factors Bax and caspase-3 in the PANC-1 cells and CFPAC-1 cells were significantly increased (P<0.05). The results of Western blot showed that treatment with ixazomib significantly decreased the protein levels of NF-κB p65 and IKK in the PANC-1 cells and CFPAC-1 cells (P<0.05), which was consistent with the results of mRNA expression. The protein levels of apoptosis factors Bax and caspase-3 in the CFPAC-1 cells were significantly increased (P<0.05), and the protein level of caspase-3 in the PANC-1 cells was increased significantly (P<0.05). However, Bax protein did not increase significantly in 10 nmol/L ixazomib group. CONCLUSION:Ixazomib, a proteasome inhibitor, inhibits the viability of pancreatic cancer cells and promotes apoptosis by inhibiting the activation of NF-κB signaling pathway in a time- and dose-dependent manner.     

Role of hypoxia stimulated expression of connective tissue growth factor in renal interstitial fibrosis

AIM: To study the expression of connective tissue growth factor (CTGF) induced by hypoxia, and the role and mechanism of hypoxia on promoting renal interstitial fibrosis. METHODS: Renal interstitial fibrosis was induced by unilateral ureteral obstruction (UUO) in rat animal model for 9 days as in vivo studies; marker of hypoxia-HIF-1α mRNA and protein, the expression of CTGF in the obstructed kidneys were assessed by RT-PCR, immunohistochemistry and Western blotting respectively. In vitro, normal rat kidney interstitial fibroblast cells (NRK-49F) were exposed to hypoxia (1%O2) for up to 6 hours, hypoxia was confirmed by detecting the expression of HIF-1α protein in cells, cellular level of CTGF mRNA and protein were assessed by RT-PCR and Western blotting respectively. RESULTS: Neither HIF-1α mRNA nor HIF-1α protein was expressed in the kidney from sham-operated group of rats. High level of HIF-1α mRNA were occurred, and strongly HIF-1α positive immunostaining were seen in the tubular and interstitial cells in kidney from UUO rats. Expression and location of CTGF protein were paralleled and relevant with the expression of HIF-1α protein in kidney of UUO rats. In cultured NRK-49F cell line, subjected to hypoxia even for 6 hours stimulated the expression of CTGF mRNA and protein. CONCLUSION: Our results indicated that hypoxia could stimulate the expression of CTGF mRNA and protein in kidney from UUO rats, which may in turn contribute to renal interstitial fibrosis.     

Effects of fluctuant high blood glucose on apoptosis in glomerular endothelial cells and renal tubular epithelial cells in diabetic rats

AIM:To explore the effects of fluctuant high blood glucose and stable high blood glucose on apoptosis and the expression of Bax and Bcl-2 in glomerular endothelial cells and renal tubular epithelial cells in diabetic rats. METHODS: 24 SD rats were divided into 3 groups: control group, stable high blood glucose group and fluctuant high blood glucose group. Diabetic rats were induced by intraperitoneal injection of STZ, and the fluctuant high blood glucose animal model was induced by intraperitoneal injection of aspart and glucose at different time points every day. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL), and immunohistochemistry was used to detect apoptosis associated gene bax and bcl-2 expression in kidney. RESULTS:After 4 experimental weeks, a significant increase in cell apoptosis, up-regulation of Bax protein expression in kidney tubular epithelial cell and down-regulation of Bcl-2 in glomerular endothelial cell in fluctuant high blood glucose rats were observed compared with stable high blood glucose rats.CONCLUSION: Fluctuant high blood glucose induces more apoptosis in renal tubular epithelial cells than that in stable high blood glucose diabetic rats.     

Effects of Le Er Mai on apoptosis of hippocampus neuronal cells in anaphase of cerebral ischemic reperfusion injury in rats

AIM: To investigate the effects and mechanism of Le Er Mai (LEM) on the apoptosis of hippocampus neuronal cells in the anaphase of cerebral ischemic reperfusion injury in rats.METHODS: A rat model of middle cerebral artery occlusion reperfusion (MCAO) was produced with the intraluminal filament. During reperfusion for 30 d after 2 h of ischemia, the TUNEL staining methods were used to detect apoptosis of hippocampus neuronal cells, and immunohistochemical technique were employed to examine the protein expression of Fas, Bax, caspase-3 and caspase-9 in the hippocampial. The gene expressions of fas, bax, caspase-3 and caspase-9 in hippocampial were examined by RT-PCR. RESULTS: After 2 h ischemia and 30 d reperfusion, compared with sham-operated group, TUNEL-positive staining cells and expression levels of Fas, Bax as well as caspase-3 and caspase-9 obviously increased, and the mRNA expressions of fas, bax, caspase-3 and caspase-9 in hippocampial markedly up-regulated in model group. Compared with model group, LEM at dose of 2.00 g/kg or 0.87 g/kg, and flunarizinum significantly reduced apoptosis and decreased the protein expressions of Fas, Bax, caspase-3 and caspase-9 in hippocampial, and down-regulated the mRNA expressions of fas, bax, caspase-3 and caspase-9 (P<0.05), those action of LEM in 0.87 g/kg dosage group was lower than those in 2.00 g/kg dosage group.CONCLUSION: LEM obviously lower the injury of hippocampial in the anaphase of cerebral ischemia reperfusion through inhibiting the apoptosis of hippocampus neuronal cells. The mechanism of LEM may be related to regulate the expression of signal transduction pathway correlated gene of apoptosis in neuronal cells.     

Effect of 27nt-miRNA on apoptosis of human umbilical vein endothelial cells induced by oxidized low-density lipoprotein

AIM To investigate the effect of 27nt-miRNA （27nt-miR） on apoptosis of human umbilical vein endothelial cells （HUVECs） induced by oxidized low-density lipoprotein （Ox-LDL） and its underlying mechanism. METHODS HUVECs were cultured in vitro and grouped as below： normal control group, Ox-LDL group, 27nt-miR+Ox-LDL group, anti-27nt-miR+Ox-LDL group and negative control+Ox-LDL group. The cells in Ox-LDL group were treated with Ox-LDL at 40 mg/L for 48 h, while those in normal control group were untreated but cultured normally. The cells in 27nt-miR+Ox-LDL group, anti-27nt-miR+Ox-LDL group and negative control+Ox-LDL group were transfected with their corresponding lentiviral vectors under the same procedure, followed by treatment with Ox-LDL at 40 mg/L for 48 h to induce apoptosis. The cell viability was measured by CCK-8 assay. The migration capacity was detected by scratch assay. The caspase-3 activity was measured by caspase-3 activity assay kit. The apoptotic rate was analyzed by Hoechst 33258 and flow cytometry. The mRNA and protein expression levels of Bcl-2, Bax and caspase-3 were determined by RT-qPCR and Western blot. RESUITS： Compared with negative control+Ox-LDL group, the cell viability and migration ability were significantly decreased by over-expression of 27nt-miR in the HUVECs （P<0.05）, while the activity of caspase-3 and apoptosis induced by Ox-LDL were significantly increased （P<0.05）. Furthermore, the mRNA and protein expression levels of Bax and caspase-3 were significantly up-regulated （P<0.05）, and the mRNA and protein expression level of Bcl-2 was down-regulated in 27nt-miR+Ox-LDL group （P<0.05）. Meanwhile, all the above indexes showed an opposite tendency in anti-27nt-miR+Ox-LDL group. CONCLUSION 27nt-miR promotes Ox-LDL-induced apoptosis and inhibits the viability and migration of HUVECs in vitro, possibly through regulating the expression of apoptotic/anti-apoptotic proteins such as Bax,caspase-3 and Bcl-2.     

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.