Downregulation of cardiac PIASy inhibits Cx43 SUMOylation and ameliorates ventricular arrhythmias in a rat model of myocardial ischemia/reperfusion injury / 中华医学杂志(英文版)

BACKGROUND@#Dysfunction of the gap junction channel protein connexin 43 (Cx43) contributes to myocardial ischemia/reperfusion (I/R)-induced ventricular arrhythmias. Cx43 can be regulated by small ubiquitin-like modifier (SUMO) modification. Protein inhibitor of activated STAT Y (PIASy) is an E3 SUMO ligase for its target proteins. However, whether Cx43 is a target protein of PIASy and whether Cx43 SUMOylation plays a role in I/R-induced arrhythmias are largely unknown.@*METHODS@#Male Sprague-Dawley rats were infected with PIASy short hairpin ribonucleic acid (shRNA) using recombinant adeno-associated virus subtype 9 (rAAV9). Two weeks later, the rats were subjected to 45 min of left coronary artery occlusion followed by 2 h reperfusion. Electrocardiogram was recorded to assess arrhythmias. Rat ventricular tissues were collected for molecular biological measurements.@*RESULTS@#Following 45 min of ischemia, QRS duration and QTc intervals statistically significantly increased, but these values decreased after transfecting PIASy shRNA. PIASy downregulation ameliorated ventricular arrhythmias induced by myocardial I/R, as evidenced by the decreased incidence of ventricular tachycardia and ventricular fibrillation, and reduced arrythmia score. In addition, myocardial I/R statistically significantly induced PIASy expression and Cx43 SUMOylation, accompanied by reduced Cx43 phosphorylation and plakophilin 2 (PKP2) expression. Moreover, PIASy downregulation remarkably reduced Cx43 SUMOylation, accompanied by increased Cx43 phosphorylation and PKP2 expression after I/R.@*CONCLUSION@#PIASy downregulation inhibited Cx43 SUMOylation and increased PKP2 expression, thereby improving ventricular arrhythmias in ischemic/reperfused rats heart.

The Outcome Impact of Early vs Late HFNC Oxygen Therapy in Elderly Patients with COVID-19 and ARDS

Coronavirus disease-2019 (COVID-19) has rapidly spread worldwide. High-flow nasal cannula therapy (HFNC) is a major oxygen supporting therapy for severely ill patients, but information regarding the timing of HFNC application is scarce, especially in elderly patients. We retrospectively analyzed the clinical data of 110 elderly patients ([≥]65 years) who received HFNC from Renmin Hospital of Wuhan University, Peoples Hospital of Xiantao City and Chinese Medicine Hospital of Shishou City in Hubei Province, China, and from Affiliated Hospital of Guangdong Medical University, Peoples Hospital of Yangjiang City, Peoples Hospital of Maoming City in Guangdong Province, China. Of the 110 patients, the median age was 71 years (IQR, 68-78) and 59.1% was male. Thirty-eight patients received HFNC when 200 mmHg < PO2/FiO2 [≤] 300 mmHg (early HFNC group), and 72 patients received HFNC treatment when 100 mmHg < PaO2/FiO2 [≤] 200 mmHg (late HFNC group). Compared with the late HFNC group, patients in the early HFNC group had a lower likelihood of developing severe ARDS, longer time from illness onset to severe ARDS and shorter duration of viral shedding after illness onset, as well as shorter lengths of ICU and hospital stay. Twenty-four patients died during hospitalization, of whom 22 deaths (30.6%) were in the late HFNC group and 2(5.3%) in the early HFNC group. It is concluded that the Prognosis was better in severely ill elderly patients with COVID-19 receiving early compared to late HFNC. This suggests HFNC could be considered early in this disease process.

Effect of propofol postconditioning on necroptosis during hypoxia-reoxygenation injury in diabetic cardiomyocytes / 中华麻醉学杂志

Objective To evaluate the effect of propofol postconditioning on necroptosis during hy-poxia-reoxygenation (H∕R) injury in diabetic cardiomyocytes. Methods Normally cultured H9C2 cardio-myocytes were divided into 5 groups (n= 19 each) using a random number table: control group (group C), high glucose group (group HG), H∕R group, propofol postconditioning (group P) and solvent dimethyl sulfoxide (DMSO) control group (group DMSO). H9C2 cells were incubated for 48 h in DMEM culture medium containing 5. 5 and 25 mmol∕L glucose in group C and group HG, respectively. In group H∕R, H9C2 cells were incubated for 48 h in DMEM culture medium containing 25 mmol∕L glucose and then un-derwent H∕R. H9C2 cells were incubated for 48 h in DMEM culture medium containing 25 mmol∕L glucose and then underwent H∕R, and propofol at the final concentration of 50 μmol∕L was added at the onset of reoxygenation in group P. In group DMSO, H9C2 cells were incubated for 48 h in DMEM culture medium containing 25 mmol∕L glucose and then underwent H∕R, and DMSO at the final concentration of 150μmol∕L was added at the onset of reoxygenation. The model of cardiomyocyte H∕R injury was established by subjecting cardiomyocytes to 6 h of hypoxia followed by 12 h of reoxygenation. At 12 h of reoxygenation, the cell viability was measured by CCK8 assay, the product of lactate dehydrogenase (LDH) in culture medium was measured, the level of reactive oxygen species (ROS) was determined by flow cytometry, cardiomyo-cyte apoptosis was detected by TUNEL, and the expression of receptor-interacting protein 1 ( RIP1), RIP3, Bax, Bcl-2, activated caspase-3 and caspase-3 was determined by Western blot. The apoptotic rate and ratio of activated caspase-3∕caspase-3 were calculated. Results Compared with group C, the cell via-bility was significantly decreased, the product of LDH was increased, the level of ROS and apoptotic rate were increased, the expression of RIP1, RIP3 and Bax was up-regulated, the expression of Bcl-2 was down-regulated, and the ratio of activated caspase-3∕caspase-3 was increased in group HG ( P < 0. 05). Compared with group HG, the cell viability was significantly decreased, the product of LDH was increased, the level of ROS and apoptotic rate were increased, the expression of RIP1, RIP3 and Bax was up-regula-ted, the expression of Bcl-2 was down-regulated, and the ratio of activated caspase-3∕caspase-3 was in-creased in group H∕R (P<0. 05). Compared with group H∕R, the cell viability was significantly increased, the product of LDH was decreased, the level of ROS and apoptotic rate were decreased, the expression of RIP1, RIP3 and Bax was down-regulated, the expression of Bcl-2 was up-regulated, and the ratio of acti-vated caspase-3∕caspase-3 was decreased in group P (P<0. 05), and no significant change was found in the indexes mentioned above in group DMSO (P>0. 05). Conclusion The mechanism by which propofol post-conditioning ameliorates H∕R injury in diabetic cardiomyocytes may be related to inhibiting necroptosis.

Expression of connexin 43 in spinal cord dorsal horn of rats with acute incisional pain / 南方医科大学学报

<p><b>OBJECTIVE</b>To examine the effect of acute incisional pain on the expression of connexin 43 in rat spinal cord dorsal horn.</p><p><b>METHODS</b>Eighty rats were assigned into control group without any treatment and incisional pain group with incision surgery. For paw incisions, a 1-cm longitudinal incision was made through the skin and fascia of the plantar aspect of the right hind paw. After surgery, the 50% paw withdrawal threshold (PWT) was assessed in response to a tactile stimulus with calibrated von Frey monofilaments at 1, 2, 4 and 24 h, respectively. The spinal cord dorsal horn of rats was isolated at 1, 2, and 4 h after the surgery to assess the expression of connexin 43 using Western blotting and immunofluorescence assay.</p><p><b>RESULTS</b>The 50% PWT of the rats was significantly decreased after the incision surgery, and this decrement was the most obvious at 2 and 4 h. Western blotting and immunofluorescence assay showed that the expression of connexin 43 in the spinal cord dorsal horn was significantly increased in rats receiving the surgery especially at 2 and 4 h after the surgery.</p><p><b>CONCLUSION</b>Incision surgery induces an significant increase in connexin 43 expression in rat spinal cord dorsal horn, suggestting an potential role of connexin43 in postoperative incisional pain.</p>

Effects of hypertonic sodium chloride hydroxyethyl starch solution on cerebral vasospasm following subarachnoid hemorrhage and its mechanism / 中华危重病急救医学

Objective To investigate the protective effect and potential mechanisms of hypertonic sodium chloride hydroxyethyl starch solution (HSH) against the cerebral vasospasm (CVS) following subarachnoid hemorrhage (SAH).Methods Twenty-four male Sprague-Dawley (SD) rats were randomly assigned to four groups according to the random number table,with 6 rats in each group.The SAH-CVS model was reproduced by injection of the blood twice through the cisterna magna.Rats in both model and HSH treatment groups received 8 mL/kg normal saline (NS) or HSH treatment everyday via caudal vein.Rats in sham group were injected with 1.5 mL/kg NS into cisterna magna followed by 8 mL/kg NS treatment.Rats in normal group received no treatment.Rats were sacrificed to harvest basilar artery after 7 days.The thickness of vessel wall and lumen area were measured using hematoxylin-eosin (HE) staining.The rate of apoptosis of vascular smooth muscle cell (VSMC) was assessed using flow cytometry.Caspase-3 activity was measured by a fluorometric assay.The expressions of Bax and Bcl-2 were determined by Western Blot.Intracellular reactive oxygen species (ROS) was detected by H2DCFDA.Results Compared with normal group,increased thickness of vessel wall (μm:27.72 ± 1.94 vs.18.30 ± 1.10,P＜0.05),decreased lumen area (μm2:26 115 ± 1 991 vs.55 080 ± 2 091,P＜0.05),and elevation of rate of apoptosis of VSMCs [(35.05 ± 5.54) ％ vs.(5.93 ± 1.53) ％,P＜ 0.05] were found in model group.Compared with model group,decreased thickness of vessel wall (μm:22.55 ± 1.50 vs.27.72 ± 1.94,P＜0.05),increase of lumen area (μm2:48 115 ±2 460 vs.26 115 ± 1 991,P＜0.05),and depressed rate of apoptosis of VSMCs [(16.54 ± 5.94) ％ vs.(35.05 ± 5.54) ％,P＜ 0.05] were found in HSH treatment group.Caspase-3 activity,intracellular ROS level,Bax and Bcl-2 expressions in model group were (188.40 ± 19.35)％,(163.50 ± 17.02)％,(208.71 ± 26.04)％ and (44.52 ± 9.61) ％ of those of normal group,and the differences of these parameters between model and normal groups were statistically significant (all P＜0.05).Caspase-3 activity,intracellular ROS level,Bax and Bcl-2 expressions in HSH treatment group were (135.05 ± 19.52)％,(119.44 ± 11.50)％,(139.20 ± 18.04)％ and (85.35 ± 13.12)％ of those of normal group,respectively,and the differences of these parameters between HSH treatment and model groups were statistically significant (all P＜0.05).The differences of all measurements between sham and normal groups were not statistically significant.Conclusion The current results demonstrate that HSH attenuates the SAH-induced CVS,alleviates thickness of vessel wall,and increases lumen area via inhibition of VSMCs apoptosis.

Effects of N-Acetylcysteine on Nicotinamide Dinucleotide Phosphate Oxidase Activation and Antioxidant Status in Heart, Lung, Liver and Kidney in Streptozotocin-Induced Diabetic Rats

PURPOSE: Hyperglycemia increases reactive oxygen species (ROS) and the resulting oxidative stress plays a key role in the pathogenesis of diabetic complications. Nicotinamide dinucleotide phosphate (NADPH) oxidase is one of the major sources of ROS production in diabetes. We, therefore, examined the possibility that NADPH oxidase activation is increased in various tissues, and that the antioxidant N-acetylcysteine (NAC) may have tissue specific effects on NADPH oxidase and tissue antioxidant status in diabetes. MATERIALS AND METHODS: Control (C) and streptozotocin-induced diabetic (D) rats were treated either with NAC (1.5 g/kg/day) orally or placebo for 4 weeks. The plasma, heart, lung, liver, kidney were harvested immediately and stored for biochemical or immunoblot analysis. RESULTS: levels of free 15-F2t-isoprostane were increased in plasma, heart, lung, liver and kidney tissues in diabetic rats, accompanied with significantly increased membrane translocation of the NADPH oxidase subunit p67phox in all tissues and increased expression of the membrane-bound subunit p22phox in heart, lung and kidney. The tissue antioxidant activity in lung, liver and kidney was decreased in diabetic rats, while it was increased in heart tissue. NAC reduced the expression of p22phox and p67phox, suppressed p67phox membrane translocation, and reduced free 15-F(2t)-isoprostane levels in all tissues. NAC increased antioxidant activity in liver and lung, but did not significantly affect antioxidant activity in heart and kidney. CONCLUSION: The current study shows that NAC inhibits NADPH oxidase activation in diabetes and attenuates tissue oxidative damage in all organs, even though its effects on antioxidant activity are tissue specific.

Effect of salvia miltiorrhiza compound on production of endothelin and thromboxane in patients undergoing CPB / 中华麻醉学杂志

Objective: To observe the effects of salvia miltiorrhizae compound (SMC) on serum endothelin (ET), TXB_2 and PGI_2 levels in patients undergoing CPB. Method: Twenty patients with congenital heart disease were randomly divided into control group (group Ⅰ) and treated group (group Ⅱ). SMC (200mg/kg) were given intravenously in group Ⅱ before operation and during rewarming, in group Ⅰ eqivalent volumes of normal saline were administered at the same time point. The serum ET,TXB_2 and PGI_2 levels were measured at preoperation (T_0) 5min (T_1), and 30min (T_2) following CPB, 10min (T_3), 30min (T_4) and 60min (T_5) following reperfusion, 24h (T_6) after operation. Result: In both groups,the serum ET level were increased significantly during reperfusion, but much less in group Ⅱ than that in group Ⅰ at T_4, T_5 and T_6(P