[Effects of PUMA knockout on the apoptosis of H9C2 cardiomyocytes induced by high glucose]

OBJECTIVE

To investigate the effects of p53 upregulated modulator of apoptosis (PUMA) on the apoptosis of H9C2 cardiomyocytes induced by high glucose and its mechanisms.

METHODS

H9C2 cardiomyocytes were treated with 5.5mmol/L (control group) or 35 mmol/L glucose (HG group) for 6 h, 12 h, 24 h or 48 h respectively to induce apoptosis, each group sets 5 multiple wells. Apoptosis was tested by TUNEL assay. PUMA mRNA was measured by RT-PCR and protein expression was measured by Western blot assay. The mitochondrial membrane potential was detected by JC-1 method. The expressions of cleaved caspase-3 and cytochrome C (Cyt C) protein in mitochondria and cytoplasm were determined by Western blot assay. H9C2 cardiomyocytes were randomly divided into four groups, control group (5.5 mmol/L), HG (35 mmol/L) group, HG+si-scramble group(si-scramble treatment for 24 h, then 35 mmol/L high glucose treatment for 24 h) and HG-si-PUMA group (si-PUMA treatment for 24 h, then 35mmol/L high glucose treatment for 24 h). Si-PUMA was transfected into cardiomyocytes and the effects of PUMA on high glucose-induced apoptosis were studied.

RESULTS

Compared with the control group, high glucose increased cardiomyocyte apoptosis and enhanced PUMA mRNA and protein expressions significantly (P＜0.05 or P＜0.01). Cell injury and increased PUMA expression were time-dependent and there was no significant difference between the high glucose 24 h group and the high glucose 48h group. The following experiment used high glucose 24 h as the stimulation time. The cardiomyocytes transfected with si-PUMA to inhibit PUMA expression had decreased apoptotic rate and cleaved caspase-3, increased mitochondria membrane potential and decreased Cyt C release (P＜0.05 or P＜0.01). There were no significant differences between the HG+si-scramble group and the high glucose group (P＞0.05).

CONCLUSION

PUMA mediates high glucose-induced cardiomyocyte apoptosis suggesting PUMA may be an important target gene of diabetic cardiomyopathy.

Effects of Angiotensin II type I receptor shRNA on blood pressure and left ventricular remodeling in spontaneously hypertensive rats

This study was designed to investigate the effects of the Angiotensin II type I receptor (AT1R) shRNA on blood pressure and left ventricular remodeling in spontaneously hypertensive rats. Ten Wistar Kyoto (WKY) rats were used as a normal blood pressure control group, and 20 spontaneously hypertensive rats (SHR) were randomly divided into the experimental and hypertension control groups. The rats in the experimental group were injected with AT1R shRNA recombinant adenovirus (Ad5-AT1R-shRNA) via a tail vein, and the rats in the other two groups were injected with recombinant adenovirus (Ad5-EGFP). The systolic blood pressure (SBP) at rat arteria caudalis was measured before and after the injection, and the heart, kidney, aorta, and adrenal tissues were obtained two days after repeated injection to observe the distribution of Ad5-AT1R-shRNA under a fluorescence microscope. Before the injection of Ad5-AT1R-shRNA, the blood pressure of the experimental group and the hypertension control group was significantly higher than that of the normal blood pressure control group (P<0.01). After two injections, the blood pressure in the experimental group decreased significantly, and the duration of blood pressure reduction reached 19 days. In the experimental group, the kidney, heart, aorta, and adrenal gland tissues showed vigorous fluorescence expression under the fluorescence microscope. Repeated administration of Ad5-AT1R-shRNA has a long-lasting hypotensive effect on SHR and can significantly improve ventricular remodeling.

Scavenger Receptor BI Induced by HDL From Coronary Heart Disease May Be Related to Atherosclerosis

This study aims to determine whether dysfunctional High Density Lipoprotein (HDL) influenced the expression of scavenger receptor class B type Ⅰ (SR-B1) to determine reverse cholesterol transport. Blood samples obtained from coronary heart disease patients confirmed by angiography were collected. HDL was extracted from the blood via ultracentrifugation. Then, the HDL was injected into apoE-/- mice, and the HepG2 cells cultured with Dulbecco's modified eagle medium (DMEM) were added the HDL extracted from coronary heart disease patients. As controls, normal cases without coronary heart disease (CHD) and patients with angina pectoris and acute myocardial infarction were used. The protein expression levels of SR-B1 were detected by western blot, and the lipid accumulation levels were detected by Oil Red O staining in both tissues and cell levels. These results revealed that the HDL obtained from CHD patients downregulate the SR-B1 expression in ex vitro and in vitro studies. In addition, dysfunctional HDL may result in lower SR-B1 expression levels. The degree of SR-B1 expression levels could be relative to the degree of coronary congestion. Along with the increase in severe coronary congestion, such as myocardial infarction, the SR-B1 expression levels were lower. The dysfunctional HDL derived from coronary heart disease patients decreased the expression of SR-B1, and promoted lipid accumulation.

Circ_BMP2K enhances the regulatory effects of miR-455-3p on its target gene SUMO1 and thereby inhibits the activation of cardiac fibroblasts

Research has shown that some circular RNAs (circRNA) are abnormally expressed in the process of myocardial fibrosis, but the mechanism behind this was unknown. In the process of inducing cardiac fibroblast (CF) activation with TGF-β1 or Ang II, the expression of circRNA circ_BMP2K and miR-455-3p were significantly inhibited, whereas the expression of SUMO1 was promoted. The results from our dual luciferase reporter gene assays, RIP assays, and pull-down assays show that miR-455-3p directly binds circ_BMP2K, thereby mutually promoting their expression levels. SUMO1 is a target gene of miR-455-3p, and circ_BMP2K enhances the inhibitory effects of miR-455-3p on the expression of SUMO1. Further study showed that both circ_BMP2K and miR-455-3p inhibited the expression of alpha-SMA as well as type I and type III collagen, whereas SUMO1 promoted their expression, and miR-455-3p inhibitors or overexpression of SUMO1 reversed the effects of circ_BMP2K and miR-455-3p. Circ_BMP2K and miR-455-3p inhibits cell proliferation and migration and promotes the apoptosis of CFs, but SUMO1 has the opposite effects; miR-455-3p inhibitors or overexpression of SUMO1 reverses the effects of circ_BMP2K and miR-455-3p. Thus, circ_BMP2K promotes the expression of miR-455-3p, down-regulates the expression of SUMO1, and finally, inhibits the activation, growth, and migration of CFs. These results could provide important therapeutic targets and a theoretical basis for regulating the process of myocardial fibrosis.

Intermedin attenuates high-glucose exacerbated simulated hypoxia/reoxygenation injury in H9c2 cardiomyocytes via ERK1/2 signaling

Objective:

This study investigated whether and how intermedin (IMD) exerted a protective effect against simulated hypoxia/reoxygenation (H/R) injury in high-glucose-treated H9c2 cells.

Methods:

Cellular viability was assessed via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Oxidative stress was determined by malondialdehyde and superoxide dismutase content in the culture medium supernatant. Flow cytometry with Annexin V/propidium iodide staining was used to detect the cardiomyocyte apoptosis rate. The protein expression of Bax, Bcl-2, caspase-3, and ERK1/2 was determined by western blot.

Results:

IMD administration to H9c2 cells during H/R injury decreased oxidative stress product generation and inhibited apoptosis ( P < 0.05 or P < 0.01) while these effects were blocked by the ERK1/2 inhibitor ( P < 0.05 or P < 0.01). Through the application of a specific ERK1/2 inhibitor, it was demonstrated that IMD mitigates high-glucose-induced oxidative stress and apoptosis via ERK1/2 signaling.

Conclusion:

Intermedin may be a novel therapeutic agent for mitigating diabetic cardiovascular injury in the clinical setting.

[Clinical application of one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery]

Objective: To summarize the results and clinical application experience of one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery. Methods: From November 2014 to July 2016, 15 patients (9 males and 6 females) with ages ranging from 50 to 73 (63.5±6.2) years requiring cardiac surgery with bradycardia underwent one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery. All operations were performed under general anesthesia with chest median incision approach. Among them, single chamber pacemaker (n=10) and dual chamber pacemaker (n=5) permanent epicardial pacing leads were implanted. Simultaneous procedures included valve replacement in 7 cases, valve replacement combined with atrial fibrillation ablation in 3 cases, coronary artery bypass grafting in 2 cases, aortic root replacement in 2 cases, and valve replacement combined with coronary artery bypass surgery in 1 case. Their parameters of pacemaker including sensitivity, pacing threshold, pacing impedance were measured during surgery and closely followed up at 1 week and 3, 6 months after surgery. Results: All 15 patients with epicardial permanent pacemaker implantation in the same period of cardiac surgery were successfully cured and discharged, without any surgical complications. A total of 20 epicardial electrodes were implanted for them including 5 right atrial electrodes and 15 right ventricular electrodes. The postoperative follow-up period ranged from 3 to 22 months. No electrode fracture and surgical wound infection occurred in those patients, and their impedance, sensing and stimulation thresholds were all in normal ranges during follow-up. Conclusions: For patients with bradycardia who required cardiac surgery, one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery is safe and effective, and the results in the short-term and medium-term are satisfactory, avoiding the risk of staged surgery.

[Robotic mitral valve repair: perioperative and seven-year follow-up results]

OBJECTIVE

To summarize surgical experience during the conduction of robotic mitral valve repair and evaluate the long-term follow-up results.

METHODS

From January 2007 to September 2014, 110 consecutive patients underwent robotic mitral valve repair under da Vinci Surgical System (Intuitive Surgical, USA) in Chinese PLA General Hospital were enrolled. The age of the patients was 14 to 65(45±12) years old. The male to female ratio was 2.3∶1. Among them, 95.5%(105/110) of the cases was diagnosed as mitral regurgitation and 4.5%(5/110) of them was diagnosed as mitral stenosis, and most of them (63.3%) needed triangular or quadrangular resection. Nitinol U-clips (58.1%), running suture (31.2%) and Cor-Knot™ suture device (10.8%) were used to secure the annuloplasty ring. The operative data were collected and patients were regularly followed up echocardiographically as long as 7 years.

RESULTS

All the surgeries were finished by the same surgeon. One case required conversion to sternotomy. The mean cardiopulmonary bypass (CPB) and cross-clamp time was 70 to 152 (121.0±34.3) and 47 to 122 (82.6±25.3) minutes respectively. After surgery, one death (0.91%) and two cases of stroke (1.82%) occurred. Three cases of early prosthetic failure (2.73%) were noticed. All patients were successfully followed up for a median of 50 (range, 1 month to 7 years) months and 94.5%(104/110) of them had no re-operation.

CONCLUSION

Robotic mitral valve repair is a safe and effective surgical method with excellent long-term outcomes.

Correlation between the High Density Lipoprotein and its Subtypes in Coronary Heart Disease

BACKGROUND/AIMS

To detect the changes of high density lipoprotein (HDL) and its subtypes in serum of patients with coronary heart disease (CHD).

METHODS

337 hospitalized patients were selected from our hospital during August, 2014 - January, 2015, and divided into CHD group (n = 190) and control group (n = 127). Lipoprint lipoprotein analyzer was used to classify low density lipoprotein (LDL) particle size and its sub-components, as well as HDL particle size and its sub-components. The changes of the subtypes in patients with CHD were statistically analyzed. The possible mechanism was explored.

RESULTS

(1) Compared with the control group, the concentration of HDL in CHD patients reduced, HDLL significantly decreased (P < 0.001), while HDLS increased (P < 0.001); (2) In the patients with HDL less than 1.04 mmol/L among CHD, all HDL subtypes reduced, but HDLL had the most significant decreased; (3) HDL and all HDL subtypes were positively correlated with apolipoprotein A-I (apoA-I), of which, HDLL had the biggest correlation with apoA-I (P < 0.001); (4) HDL subtypes had good correlation with HDL, of which, HDLM had a maximum correlation with HDL (P < 0.001).

CONCLUSION

HDL maturation disorders existed in the serum of CHD patients, HDLL may be protected factor for CHD, whose decrease was closely related wit the risk increase of CHD. The cardiovascular protection function of HDLL may be related with apoA-I content.

Angiotensin-(1-7) treatment ameliorates angiotensin II-induced apoptosis of human umbilical vein endothelial cells

Angiotensin (Ang)-(1-7), a metabolite of AngI and AngII, is a counter-regulatory mediator of AngII. In the present study, we investigated the effects of Ang-(1-7) on AngII-induced apoptosis in human umbilical vein endothelial cells (HUVEC). To this end, HUVEC were pretreated with 10(-9), 10(-8), 10(-7) or 10(-6) mol/L Ang-(1-7) at for 30 min before being stimulated with 10(-6) mol/L Ang-II for another 24 h. Acridine orange/ethidium bromide and propidium iodide staining were used to analyse the effects of Ang-(1-7) on AngII-induced apoptosis. Alone, 10(-6) mol/L Ang-(1-7) had no effect on the apoptosis of HUVEC following exposure of cells for 30 min, whereas AngII (10(-6) mol/L, 24 h) significantly enhanced the number of apoptotic cells (P < 0.01). The AngII-induced apoptosis of HUVEC was suppressed by 10(-9)-10(-6) mol/L Ang-(1-7). The anti-apoptotic effects of Ang-(1-7) were almost completely abolished by A-779 (10(-6) mol/L, 30 min), a specific Mas receptor antagonist. In addition, Ang-(1-7) inhibited AngII-induced accumulation of cleaved caspase 3 and enhanced the expression of the anti-apoptotic factor Bcl-2 at both the mRNA and protein levels. Angiotensin II upregulated the expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), which is involved in endothelial apoptosis, at both the mRNA and protein levels. This effect was blocked by Ang-(1-7) in a concentration-dependent manner, although A-779 almost completely reversed Ang-(1-7)-mediated inhibition of AngII-induced upregulation of LOX-1. Silencing of LOX-1 using short interference RNA enhanced the protective effects of Ang-(1-7) against AngII-induced apoptosis in HUVEC. Together, the results suggest that Ang-(1-7) ameliorates AngII-induced apoptosis of HUVEC at least in part by suppressing LOX-1 expression.

[Adiponectin up-regulates the expression of T-cadherin in cardiomyocytes injured by hypoxia/reoxygenation]

The aim of the present study was to investigate the effects of adiponectin (APN) on the expression of T-cadherin in cultured Sprague-Dawley (SD) rat cardiomyocytes injured by hypoxia/reoxygenation (H/R). Primary myocardial cells from neonatal rats were obtained by enzymatic digestion. The cells were divided into control group, H/R group and H/R+APN (3, 10, 20 and 30 μg/mL) groups. The H/R group was incubated in anoxic environment (anoxic solution saturated with high concentration N2) for 3 h, and then in the reoxygenation environment (the reoxygenation solution saturated with pure oxygen) for 1 h. The H/R+APN group was pretreated with different concentrations of APN for 24 h prior to the initiation of H/R. The content of lactate dehydrogenase (LDH) was measured by chemistry chromatometry. Cellular apoptosis was analyzed by flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The expression of T-cadherin was detected by RT-PCR and Western blotting. The results showed that, compared with control group, the apoptotic rate and release of LDH were significantly increased in the H/R group, whereas the expressions of T-cad mRNA and protein were decreased. Pretreating with APN significantly and dose-dependently decreased apoptotic rate and LDH release, and up-regulated T-cad mRNA and protein level in rat neonatal cardiomyocytes under H/R conditions. These results suggest that APN may protect cardiomyocytes against H/R-induced injury by up-regulating H/R-decreased T-cad expression.

Angiotensin-converting enzyme (ACE) gene insertion/deletion polymorphism and ACE inhibitor-related cough: a meta-analysis

OBJECTIVE

An insertion/deletion (I/D) variant in the angiotensin-converting enzyme (ACE) gene was associated with ACE inhibitor (ACEI)-related cough in previous studies. However, the results were inconsistent. Our objective was to assess the relationship between the ACE I/D polymorphism and ACEI-related cough by meta-analysis and to summarize all studies that are related to ACE I/D polymorphism and ACEI-cough and make a summary conclusion to provide reference for the researchers who attempt to conduct such a study.

METHODS

Databases including PubMed, EMbase, Cochrane Library, and China National Knowledge Infrastructure, were searched for genetic association studies. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. Metaregression and subgroup analyses were performed to identify the source of heterogeneity.

RESULTS

Eleven trials, including 906 cases (ACEI-related cough) and 1,175 controls, were reviewed in the present meta-analysis. The random effects pooled OR was 1.16 (95%CI: 0.78-1.74, p=0.46) in the dominant model and 1.61 (95%CI: 1.18-2.20, p=0.003) in the recessive model. Heterogeneity was found among and within studies. Metaregression indicated that the effect size was positively associated with age and negatively associated with follow-up duration of ACEI treatment. Subgroup analysis revealed a significant association between ACE I/D polymorphism and ACEI-related cough in studies with mean age >60 y, but not in studies with mean age ≤ 60 y. No heterogeneity was found within each mean age subgroup. We also found no association between ACE I/D polymorphism and ACEI-related cough in studies with follow-up>2 mo or in studies in Caucasians. No heterogeneity was detected in these two subgroups.

CONCLUSIONS

Synthesis of the available evidence supports ACE I/D polymorphism as an age-dependent predictor for risk of ACEI-related cough.

Endogenous aldosterone is involved in vascular calcification in rat

Aldosterone (Aldo) is an important active hormone in the renin–angiotensin–aldosterone system and plays a vital role in the development of hypertension, heart failure and other cardiovascular diseases. We aimed to explore the role of endogenous Aldo in aortic calcification in rats. We induced arterial calcification in rats by intramuscular administration of vitamin D3 plus oral nicotine (VDN) and determined calcium content, 45Ca2+ accumulation and activity of alkaline phosphatase (ALP). The mRNA level of osteopontin (OPN) was measured by semi-quantitative reverse transcriptase polymerase chain reaction. Deposition of collagen in the aorta wall was measured by Sirius red staining. The content of angiotensin II (Ang II) and Aldo in plasma and myocardial and vascular tissue was determined by radioimmunoassay. In rats with VDN treatment, von Kossa staining showed calcification in vascular smooth muscle cells and extracellular matrix, and the content of calcium in calcified arteries was 5.8-fold of that in control arteries ( P < 0.01). The accumulation of 45Ca2+ and activity of ALP in calcified aortic tissue was three- and 2.5-fold, respectively, that in control tissue ( P < 0.01). The mRNA expression of OPN was significantly higher, by 58%, in calcified than control tissue ( P < 0.01). Vascular fibrosis was greater in rats with calcified tissue than in control rats. The level of Ang II and Aldo was 58% and 80% higher, respectively, in calcified than control tissue (both P < 0.01). The changes could be significantly improved by treatment with captopril, an angiotensin-converting enzyme inhibitor, and the Aldo receptor antagonist spironolactone. These results suggest that Aldo is an endogenous bioactive factor involved in vascular calcification.

[Glucagon like peptide-1 inhibits high glucose-induced injury of oxidative stress in cardiomyocytes of neonatal rats]

The present study was to investigate the effect of glucagon like peptide-1 (GLP-1) on high glucose-induced oxidative stress of cardiomyocytes and the possible role of the PI3K-Akt signal path in this process in the neonatal SD rats. With enzymatic digestion and immunofluorescence identification, cardiomyocytes after 72-96 h of primary culture were used in experiment. The cells were divided into 5 groups: normal control group, high glucose group, high glucose + GLP-1 group, high glucose + GLP-1 + LY294002 group and high osmolarity control group. The content of MDA was detected by TBA colouration method. The content of SOD was detected by xanthine oxidase method. The change of NADPH P47phox subunit mRNA quantity was detected by PCR gel electrophoresis. The level of ROS was detected by flow cytometry, and was also observed by fluorescence microscope. The DNA ladder was examined by agarose gel electrophoresis, and the cell apoptosis was determined by Annexin-V-FITC/PI flow cytometry, and the phosphorylation of Akt was determined by Western blotting. Compared with those in the normal control group, in the high glucose group, the cells grew poorly, and the beating rate was significantly lower (P < 0.05); The apoptotic rate was significantly increased (P < 0.05); The MDA content was increased (P < 0.05); It showed the typical DNA ladder, which is the characteristic of apoptosis; The SOD activity was decreased (P < 0.05); The level of intracellular ROS increased (P < 0.05); And the expression of NADPH P47phox subunit mRNA was increased; However the phosphorylation level of Akt was decreased. Pretreatment with GLP-1 improved the above-mentioned parameters and decreased the expression of NADPH P47phox subunit mRNA (P < 0.05). However, compared with the high glucose + GLP-1 group, LY294002, an inhibitor of PI3K-Akt signal path, attenuated the protective effect of GLP-1 in the high glucose + GLP-1 + LY294002 group. It is suggested that GLP-1 plays a protective role in the high glucose-induced injury and apoptosis of cardiomyocytes, and the PI3K-Akt signal path is involved in this process.

[Protective effects of adiponectin against hypoxia/reoxygenation injury in neonatal rat cardiomyocytes]

The aim of the present study is to investigate the effects of adiponectin (APN) on hypoxia/reoxygenation (H/R) injury in cultured cardiomyocytes. Primary cardiomyocytes were obtained from neonatal rats by enzymatic digestion method and identified by immunofluorescent technique. Primary cells cultured for 72 h were used in experiment and divided into 5 groups randomly: Control group, H/R group, H/R+APN group, H/R+APN+adenine 9-beta-D-arabinfuranoside (AraA, AMPK inhibitor) group, and H/R+AraA group. The cardiocyte morphology and beating rate were observed under inverted microscope. The DNA ladder was examined by agarose gel electrophoresis, and the cell apoptosis was determined by flow cytometry. Moreover, the malondialchehyche (MDA) content in myocardial cells and the superoxide dismutase (SOD) activity in the supernatant were measured using kits, the fluorescence intensity of intracellular Ca2+ was observed by laser scanning confocal microscope, and the phosphorylation of AMPK was determined by Western blotting. Compared with control group, H/R group showed increased apoptotic rate, oxidative stress level, intracellular Ca2+ concentration and phosphorylation level of AMPK (P<0.05), while significant ameliorations in the above indices were seen in H/R+APN group. On the contrast, AraA attenuated the protective effect of APN and decreased the phosphorylation of AMPK. These results suggest that adiponectin can protect cardiomyocytes from H/R-induced oxidative stress and apoptosis through AMPK pathway.

Calcium sulfide (CaS), a donor of hydrogen sulfide (H(2)S): a new antihypertensive drug?

Hypertension is the leading cause of cardiovascular diseases, and an estimated 972 million people in the world are suffering from this problem. Indubitably, hypertension is an important worldwide public-health challenge. In recent years many efforts have been made to devise novel therapies involving new targets implicated in cardiovascular diseases. Hydrogen sulfide (H(2)S) is a member of a growing family of "gasotransmitters". It is clear that H(2)S plays a pivotal role in the basal regulation of vessels tone. Also studies demonstrate that intravenous sodium hydrosulfide (NaHS), a donor of H(2)S, dose-dependently decreases systolic blood pressure. However, because of its active chemical property, NaHS can be easily oxidized, even spontaneously ignited in the open air. Moreover, its solution is not stable. So the pharmacal use of NaHS is limited by its properties. Calcium sulfide (CaS), one of the effective components in a traditional herb, is another donor of H(2)S. It has more stable chemical properties than NaHS. We hypotheses that CaS might be given by mouth as a new antihypertensive drug through certain dosage form designing. To test this hypothesis, we should establish animal models for studies including drug efficacy, drug safety, drug toxicology, drug metabolism and drug kinetics.

[Effects of RNA interference targeting angiotensin-converting enzyme on the blood pressure and myocardial remodeling in spontaneously hypertensive rats]

OBJECTIVE

To investigate the effects of RNA interference (RNAi) targeting angiotensin-converting enzyme (ACE) on the blood pressure and myocardial remodeling in spontaneously hypertensive rats (SHRs).

METHODS

Saline (control), adenovirus (Ad5) and recombinant adenoviral vectors (Ad5-ACE-shRNA expressing ACE gene-specific shRN) were randomly administered by caudal intravasation to SHRs (n = 12 each group) at day 1 and day 16. Normotensive Wistar-Kyoto rats (WKY) served as normal controls. Systolic blood pressure (SBP) of the caudal artery was measured daily. Expressions of ACE at mRNA and protein levels in myocardium and aorta were evaluated by RT-PCR and Western blot respectively, ACE serum concentration was measured by ELISA at day 3 (n = 6 each group). The ratio of left ventricular to body weight (LVW/BW), myocardial collagen content were measured and myocardial ultrastructure observed under transmission electron microscope at the study end.

RESULTS

Ad5-ACE-shRNA injection significantly reduced SBP (-22 mm Hg, 1 mm Hg = 0.133 kPa) and the antihypertensive effect could last at least 14 days post each injection. SBP was not affected by saline and Ad5 injections. ACE expressions at mRNA and protein levels at myocardium and aorta as well as serum ACE were significantly decreased in Ad5-ACE-shRNA treated SHRs compared to that in saline and Ad5 groups (all P < 0.05) and was comparable to that in WKY group (P > 0.05). The LVW/BW ratio (2.24 +/- 0.19) and myocardial collagen content [(1.283 +/- 0.019) microg/mg] in Ad5-ACE-shRNA treated SHRs were also significantly lower than those in saline treated [3.21 +/- 0.13 and (1.686 +/- 0.013) microg/mg, both P < 0.05] and Ad5 treated SHRs [3.13 +/- 0.12, (1.682 +/- 0.009) microg/mg, both P < 0.05] but still higher than those of WKY group [2.06 +/- 0.11, (1.257 +/- 0.019) microg/mg, both P < 0.05]. Myocardial ultrastructure was also significantly improved in Ad5-ACE-shRNA treated SHRs compared to saline and Ad5 treated SHRs.

CONCLUSION

RNAi targeting ACE gene significantly inhibited the expressions of ACE at mRNA and protein levels and resulted in prolonged antihypertensive effects and myocardial ultrastructure improvements in this SHR model.

[The effects of shRNA targeting angiotensin II type 1 receptor on blood pressure and AT1R mRNA expression in spontaneously hypertensive rats]

OBJECTIVE

To investigate the effects of retroviral vector containing shRNA targeting rat angiotensin II type 1 receptor (AT1R) gene (Ad5-AT1R-shRNA) on blood pressure and AT1R mRNA expression in spontaneously hypertensive rats (SHR).

METHODS

Retroviral vector containing shRNA targeting rat AT1R gene was constructed and propagated further in 293 cells. SHR rats were randomly divided into SHR + Ad5-AT1R-shRNA (1.7 x 10(9) TCID(50)/ml) group and SHR (Ad5-EGFP, 7.9 x 10(9) TCID(50)/ml, n = 11 each) and 11 male Wistar-Kyoto rats (WKY) serve as normal controls (Ad5-EGFP, 7.9 x 10(9) TCID(50)/ml). Systolic blood pressure was measured before and after single intravenous injection of Ad5-AT1R-shRNA or Ad5-EGFP. Heart, liver, kidney, aorta and adrenal gland were removed after blood pressure measurement. Tissue Ad5-AT1R-shRNA expression was detected with fluorescence microscope and AT1R mRNA in liver, kidney and aorta was measured by fluorescence quantitative PCR.

RESULTS

Ad5-AT1R-shRNA significantly reduced blood pressure compared with controls (-29 mm Hg, 1 mm Hg = 0.133 kPa, P < 0.05) 24 hours after single injection and this antihypertensive effect could last for 5 to 7 days. Ad5-AT1R-shRNA expression detected with fluorescence microscope was significantly increased in heart, liver, kidney, aorta and adrenal gland post Ad5-AT1R-shRNA injection. AT1R mRNA in kidney and aorta (0.086 +/- 0.014, 0.051 +/- 0.023) were significantly decreased in Ad5-AT1R-shRNA treated rats compared with SHR control rats (0.362 +/- 0.042, 0.463 +/- 0.045, P < 0.01).

CONCLUSION

The results indicate that Ad5-AT1R-shRNA could inhibit the tissue AT1R mRNA expression and produce prolonged antihypertensive effects in SHR rats.

Intracoronary trimetazidine does not improve recovery of regional function in a porcine model of repeated ischemia

We evaluated the effect of trimetazidine (TMZ) on recovery of regional cardiac function in anesthetized open-chest pigs, subjected to fifteen 2-minute occlusions of the left anterior descending coronary artery, separated by 2 minutes of reperfusion and a 120-minute recovery period. Regional myocardial function was evaluated by sonomicrometry-derived segment lengthening and the area enclosed by the left ventricular pressure-segment length loop (external work, EW) in animals, which received either an intracoronary infusion of TMZ (33 micrograms/kg/min, n = 6) or saline (1 ml/min, n = 7), starting 15 minutes before the first occlusion and ending 2 minutes after the 15th occlusion. In addition, myocardial malondialdehyde production to evaluate oxygen free radical production, oxygen consumption, and the ATP, ADP, and AMP content, as well as the energy charge, were determined at regular time intervals. In control pigs the sequences of occlusion-reperfusion did not affect systemic hemodynamics, except for the LVdP/dtmax, which decreased by 11% during the interventions and did not recover during the following reperfusion period of 2 hours (78% of baseline, p < 0.05). Systolic segment length shortening and EW were increased at the end of the first occlusion-reperfusion cycle, decreased gradually during the remainder of the occlusion-reperfusion periods, and did not improve during the recovery period. Energy charge and myocardial blood flow were not impaired, but oxygen consumption was decreased during the recovery period. The malondialdehyde data did not provide evidence for production of oxygen free radicals.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolongation of epidural bupivacaine analgesia with glycerin

Glycerin has been used as a drug carrier/depot, but never with local anaesthetics. This study was an attempt to use the slow drug release mechanism to prolong the anaesthetic effects of bupivacaine in epidural block. Twenty-seven adults with cancer pain were prospectively selected according to their primary lesions and problems, but their allocation to study groups was randomized. Group I (n = 13), received 5 ml bupivacaine, 0.125% in normal saline via a previous implanted epidural catheter. When the pain returned to its original intensity, the same amount of the same strength anaesthetic dissolved in 50% glycerin was given via the same catheter. Group II (n = 14) received the same solutions, but in the reverse order. Also five patients in each group received plain 50% glycerin prior to administration of the anaesthetic solutions to serve as controls. The pharmacological effects were assessed by the blinded observers. Analgesia produced with glycerin solution was prolonged compared with the saline solution (12.2 vs 7.2 and 11.6 vs 7.4 hr, P < 0.01). The order of giving the solution did not produce any differences. Plan 50% glycerin did not produce analgesic effects. Neither motor blockade nor other adverse effects or complications were observed in either group. It was concluded that 0.125% bupivacaine in 50% glycerin administered epidurally is not neurotoxic. The prolongation of analgesia observed is attributed to the slow release of bupivacaine from the glycerin base which functions as drug depot. In addition to relief of chronic pain, this novel approach may have other clinical applications such as the relief of labour or postoperative pain.

[Isolation and fermentation conditions of polyvinyl alcohol-degrading enzyme producing strain]

A bacterium D8 strain which high efficiently degrading PVA was isolated from waste water of factory. The strain possesses the abilities of completely degrading 0.5 per cent of PVA (500, 1700) included in the culture medium for four days. It was identified Pseudomonas pseudoalcaligenes. Fermentation conditions of the strain have been investigated. The suitable medium consisted of PVA 1.5% (NH4)2SO40.1%, K2HPO4 0.24%, KH2PO4 0.04%, MgSO4.7H2O 0.035%, NaCl 0.01%, FeSO4 0.001%, yeast extract 0.15%, pH 7.5. The optimal condition for enzyme production are as follows: 250 ml shake filled with 30 ml medium, 30 degrees C, 160n/min incubation period 72 h. Under such conditions enzyme activity is highest.

[Studies on harmful microbes in recirculating cooling water system of oil refinery]

The microbiol counts, type, distribution as well as interrelation between microbial counts and biofouling of the main harmful microbes including slimeforming heterotrophic bacteria, sulfate reducing bacteria, iron bacteria and fungi has been studies in 16 oil refineries of China. The control guideline of the harmful microbes for recirculating cooling water system of refinery were suggested, that is slime-forming bacteria less than 10(5)/ml, sulfate reducing bacteria less than 10(2)/ml. iron bacteria less than 10(3)/ml, fungi less than 10/ml. The appearing rate of the predominant strains from cooling water system of various refineries were calculated and identified and the composition of the main harmful representative microbes in cooling water system were determined.