Objective To investigate whether cigarette smoke promote endoplasmic reticulum associated apoptosis gene Caspase-12 expression. Methods Forty adult male Wistar rats were randomly divided into four groups, ie. group A ( control group) , group B ( exposed to cigarette smoke for two months) ,group C ( exposed to cigarette smoke for four months) , and group D ( exposed to cigarette smoke for four months, then quit smoking for one month) . The COPD rat model was established with passive smoking.Percentage of forced expiratory volume in first 0. 3 second to forced vital capacity ( FEV0. 3 /FVC) and peak expiratory flow ( PEF) were measured. Reverse transcriptase-polymerase chain reaction ( RT-PCR) was used to determine the mRNA expression of Caspase-12. Immunohistochemistry and Western blot were used todetermine the protein expression of Caspase-12. Caspase-12-fluorometric-assay-kit was used to determine Caspase-12 activity. Results The pulmonary function decreased ( P lt; 0. 05) and the lung structure was damaged in the group B compared with the group A. The lung function markedly decreased( P lt; 0. 05) andthe lung structure was obviously damaged in the group C compared with the group B. The pulmonary function had minor improvement( P gt; 0. 05) , and the lung structure injury was also significant in the group D in contrast with the group C. The expression and activity of Caspase-12 were remarkably increased in the group B compared with the group A( P lt; 0. 05) , elevated significantly in the group C compared with the group B ( P lt; 0. 05) , decreased slightly in the group D compared with the group C ( P gt; 0. 05 ) . Conclusion Cigarette smoke promotes the development of COPD by inducing the endoplasmic reticulum associated apoptosis gene Caspase-12 expression.
Objective Endoplasmic reticulum stress (ERS) mediated apoptosis is one of the eukaryotic cellularapoptotic pathways, to investigate the potential role of ERS during myocardium apoptosis in rats with severe burninjury. Methods Sixty-four 7-week-old male Wistar rats, weighing 200-220 g, were randomly divided into 2 groups. Thirtypercentage of total body surface area full-thickness thermal injury was produced in 32 rats of burn group, while sham burn wasproduced in 32 rats of control group. The heart tissues were harvested from 8 rats in each group at 1, 4, 7, and 14 days after burnto observe the changes of myocardium ultrastructure with transmission electron microscope (TEM). Myocardium apoptosis wasdetected with TUNEL assay. The expressions of glucose regulated protein 78 (GRP 78), C/EBP-homologous protein (CHOP),and cleaved Caspase 12 in different pathways of ERS were analysed with Western blot. Results All rats survived during theexperiment. Apoptotic changes of cardiomyocytes were observed in burn group, and the apoptosis index in burn group wassignificantly higher than that in control group at each time point (P lt; 0.05), and it reached peak at 7 days after burn injury(P lt; 0.05). The expressions of myocardial GRP 78, CHOP, and cleaved Caspase 12 showed persistent elevation in burn group.The expressions of GRP 78 and cleaved Caspase 12 in burn group were significantly higher than those in control group at eachtime point (P lt; 0.05), while the expression of CHOP was higher than that in control group at the other time points (P lt; 0.05)except 1st day after burn injury. Conclusion ERS and CHOP, Caspase 12 mediated apoptotic pathway are activated inmyocardium after severe burn injury, and this may be one pathway of myocardium apoptosis.
Objective To realize the research progress of regulating the endoplasmic reticulum stress response to inhibit autophagy in tumor cells. Method The literatures about regulating the endoplasmic reticulum stress response to inhibit autophagy in tumor cells were reviewed. Result In the endoplasmic reticulum stress response induced by the release of calcium and accumulation of unfolded proteins, autophagy can be activated by several pathways, and to regulate physiological and pathological processes. Conclusion Further research about the endoplasmic reticulum stress response in tumor cells need to be done to regulate the response factors to inhibit autophagy.
The aim of the current study is to investigate the effect of visfatin on cardiomyocyte hypertrophy. Cultured H9c2 cardiomyocytes were exposed to visfatin at different concentrations for different periods of time, and the markers of cardiomyocyte hypertrophy were detected. Moreover, pravastatin, the inhibitor of endoplasmic reticulum stress (ERS) or thapsigargin, an ERS agonist was used respectively to pre-treat the cells before visfatin stimulation. F-actin staining was performed to measure the cell surface change. The mRNA expressions of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP)and ERS markers including glucose-regulated protein 78(GRP78), C/EPB homologous protein (CHOP) and activating transcription factor 6 (ATF6) were assessed by real time RT-PCR. The change of protein level of GRP78 and CHOP was detected by Western blot. The experimental data demonstrated that exposure to 100 or 150 ng/mL concentrations of visfatin for 24 h, or 100 ng/mL of visfatin for 24 or 48 h, significantly increased the expression of markers for cardiomyocyte hypertrophy. Visfatin stimulation provoked ERS in H9c2 cells. Furthermore, pre-treatment with pravastatin partially inhibited the visfatin-induced mRNA expression of ANP and BNP in H9c2 cells, whereas thapsigargin promoted the visfatin-induced expression of cardiomyocyte hypertrophy markers. The results suggest that visfatin might induce cardiomyocyte hypertrophy via ERS -dependent pathways.
This study aims to investigate the role of calreticulin in (CRT) pressure overload induced cardiac hypertrophy. In our study, cardiac hypertrophy was induced by left ventricular pressure overload in male SD rats subjected to transverse aortic constriction (TAC) operation. Expression of gene and protein of calreticulin, markers of cardiac hypertrophy and endoplasmic reticulum stress (ERS) were measured with real-time qPCR and Western blot respectively. Meanwhile, atorvastatin (a known ERS inhibitor) and calreticulin-specific small interference ribonucleic acid (siRNA) were used to inhibit the expression of ERS and calreticulin respectively. The experimental data demonstrated that the gene and protein levels of calreticulin, hypertrophic and ERS markers were increased significantly in the heart tissues of TAC rat models after 4 weeks. Moreover, atorvastatin administration improved the cardiac function and reduced the expression of calreticulin and ERS markers in TAC rats. In addition, cultured primary neonatal rat cardiomyocytes (NCMs) were treated with norepinephrine (NE), angiotensionⅡ (AngⅡ) or isoprenaline (ISO) to induce hypertrophic phenotype and ERS. The expression of hypertrophic markers was reduced in NCMs transfected with calreticulin-siRNA. The results suggested that calreticulin might be a promising target for the treatment of cardiac hypertrophy.
ObjectiveTo investigate the endoplasmic reticulum stress associated apoptosis gene Caspase-12 expression in paraquat-induced pulmonary fibrosis. Methods30 adult healthy Sprague-Dawley(SD) rats were randomly divided into a nomal control group,two pulmonary fibrosis model groups (intragastrically administered paraquat for 14 days and 28 days,respectively).The model of pulmonary fibrosis was established through intragastrically administering paraquat at the dose of 30 mg/kg.RT-PCR was used to determine the mRNA expression of Caspase-12.Immunohistochemistry was used to determine the protein expression of Caspase-12.HE staining and Masson staining were used to determine the degree of alveolitis and pulmonary fibrosis. ResultsHE staining and Masson staining of lung tissues proved that pulmonary fibrosis model was successfully constructed.The degree of alveolitis and pulmonary fibrosis in the model group was significantly more serious than that in the control group(P<0.01).RT-PCR and Immunohistochemistry results showed that the expression of Caspase-12 were remarkably increased in the pulmonary fibrosis model group(14 d group)(P<0.01),even more elevated in 28 d group compared with the 14 d group. ConclusionThe results demonstrate that the expression of Caspase-12 in paraquat poisoned rats is up-regulated,suggesting endoplasmic reticulum stress plays an important role in paraquat induced-pulmonary fibrosis.
Objective To investigate the protective effect of 4-phenylbutyric acid (PBA) on liver injury induced by severe acute pancreatitis (SAP) in rats and its possible mechanism. Methods Twenty-four SPF adult male Sprague Dawley rats were randomly divided into three groups: shame operation group (SO group,n=8), SAP group (n=8), and PBA group (n=8). SAP model was induced by retrograde injection of 5% sodium taurocholate (1 mL/kg) in biliopancreatic duct in SAP group and PBA group. PBA solution (50 mg/kg) was administeredvia intraperitoneal injection for 3 days prior to establishing models in PBA group. Rats were injected equivalent saline solution instead of PBA solution in SAP group and SO group. All rats were sacrificed at 12 h after modeling. Blood samples were collected by inferior vena cava puncture, and serum levels of amylase (AMY), alanine aminotransferase (ALT), and aspartate transaminase (AST) were measured using a fully automatic chemistry analyzer. The head of pancreas and right lobe of hepatic tissues were harvested and pathological examination was observed under the light microscope. Expressions of glucose-regulated protein 78 (GRP78), CCAAT/enhancer binding protein homologous protein (CHOP) and Caspase-3 in hepatic tissues were evaluated by immunohistochemistry assay. Results Compared with SO group, the serum levels of AMY, ALT and AST were significantly increased in SAP group (P＜0.05). The serum levels of ALT and AST in PBA group were significantly lower than those in SAP group (P＜0.05). There was no difference of the serum levels of AMY between in PBA group and SAP group (P＞0.05). Compared with SO group, the damages of the pancreas and liver tissues and the expressions of GRP78, CHOP and Caspase-3 in hepatic tissues were significantly increased in SAP group (P＜0.05). And the above indices in PBA group were significantly decreased when compared with SAP group. Conclusions PBA can alleviate severe acute pancreatitis-induced liver injury, and the mechanism may be associated with inhibition of endoplasmic reticulum stress (ERS) and reduction of hepatocyte apoptosis.
Metabolic memory means if the hyperglycemia can't be controlled at early stage of diabetes, chronic complications such as diabetic retinopathy (DR) will continue to develop even if the blood glucose level maintains normal level at later stage. Oxidative stress plays an important role in the "metabolic memory" of DR, which interacts with the nitrative stress, advanced glycation end products, genetic modification and endoplasmic reticulum stress in the pathogenesis of DR. Further elucidation of the relationship between oxidative stress and "metabolic memory" of DR can open the way for the discovery of novel therapeutic targets to prevent DR progression.
Objective To explore the mechanism of chronic intermittent hypoxia (CIH) on renal damage with normal diet and high-fat diet. Methods Twenty-four healthy male Wistar rats of SPF grade were randomly divided into 4 groups (n=6 in each group), namely group A (normoxia and common diet), group B (normoxia and high fat diet), Group C (CIH and common diet), and group D (CIH and high fat diet). The serum cystatin C (Cys-C) was measured and the renal CHOP protein was detected by immunohistochemistry. The ultrastructural changes of glomeruli and renal tubules were observed under electron microscope. Results The levels of Cys-C in group B, group C and group D were significantly higher than those in group A (P<0.05). The mean density of endoplasmic reticulum stress (ERS) marker protein CHOP in group B, group C and group D was significantly higher than that in group A (P<0.05). Electron microscope revealed focal nuclear pyknosis in the partly renal tubular epithelial cells, sparse and scattered brush border in group B and group C, also revealed nuclear pyknosis in a large number of tubular epithelial cells, sparse and scattered brush border in group D. Conclusion CIH can activate the ERS mediated renal tubular epithelial apoptosis, thus induce ultrastructure changes and damage of kidney.