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.
Rats ; Male ; Animals ; Myocardial Reperfusion Injury/metabolism* ; Connexin 43/genetics* ; Sumoylation ; Down-Regulation ; Rats, Sprague-Dawley ; Arrhythmias, Cardiac/drug therapy* ; Myocardial Ischemia/metabolism* ; RNA, Small Interfering/metabolism*

Objective:To investigate the relationship between spinal Mas-related gene receptor C (MrgC) and pathophysiological mechanism of bone cancer pain in mice.Methods:Forty male C3H/HeNCrlVr mice, aged 5-7 weeks, weighing 20-25 g, were selected and divided into 4 groups ( n=10 each) using a random number table method: sham operation group (group S), bone cancer pain group (group P), bone cancer pain + MrgC agonist group (group P-agonist) and bone cancer pain + Mrg C antagonist group (group P-Ab). Preparation of the bone cancer pain model: mouse fibrosarcoma cells (NCTC2472) were injected into the upper tibia of mice in P, P-agonist and P-Ab groups, and the equal volume of D-Hanks balanced salt solution was given instead in S group. Fourteen days later cerebrospinal fluid was intrathecally injected in S and P groups, and MrgC agonist and MrgC antibody were intrathecally injected in P-agonist and P-Ab groups. The mechanical paw withdrawal threshold (MWT) to von Frey stimuli was measured before developing the model (T 0), at 7 days after developing the model (T 1), at 14 days after developing the model (before intrathecal injection, T 2), and at 4, 8 and 12 h after intrathecal injection (T 3-5). Results:Compared with group S, no significant change was found in the MWT at T 0 ( P>0.05), and the MWT was significantly decreased at T 1-T 5 in the other groups ( P<0.05). Compared with group P, the MWT was significantly increased at T 3-T 5 in group P-agonist, and the MWT was significantly decreased at T 3-T 5 in group P-Ab ( P<0.05). Conclusions:Spinal MrgC plays an endogenous protective role in the pathophysiological mechanism of bone cancer pain to a certain extent in mice.

In recent years, point of care ultrasound (POCUS) has developed rapidly in the fields of anesthesia and critical care. POCUS is widely used in clinic to monitor the function of human tissues and organs such as the heart, lungs, and diaphragm due to its visual, non-invasive, portable, and repeatable characters at the bedside. Diaphragm is an important structure to maintain respiratory function. Diaphragm paralysis or dysfunction can cause a significant decrease in inspiratory function. The patient's diaphragm function can be assessed through monitoring diaphragm thickness and activity by POCUS, and combined with other clinical indicators, the patient's recovery of respiratory function can be comprehensively evaluated, and rapidly identify the pathological conditions, such as diaphragm paralysis, diaphragm atrophy, diaphragmatic hypoplasia and amyotrophic lateral sclerosis. Dynamic evaluation of the process from diaphragmatic dysfunction to recovery can provide guidance for weaning and extubation, and real-time feedback on the treatment effect. This article reviews the ultrasound evaluation methods and clinical applications to the diaphragm, in order to guide clinicians to use relevant indicators to comprehensively evaluate the structure and function of the diaphragm, and then diagnose and treat diaphragm dysfunction, which may help making clinical decision.

Inflammatory response is an effective host defense mechanism to eliminate pathogens at the site of infection. The regression phase of inflammation mainly maintains the stable environment in tissues. Pro-inflammatory regression mediators (SPMs) are endogenous anti-inflammatory molecules, which play an important role in reducing excessive tissue damage and chronic inflammation. This paper reviews the interaction between SPMs and immune cells in inflammatory sites. By reviewing the relevant literature, it was found that SPMs regulate the components of innate and adaptive immune system, including neutrophils, macrophages, innate lymphocytes, natural killer cells and T cells.

Objective To explore the effect of Protectin DX(PDX) on acute liver injury(ALI) induced by sepsis in mice and the underlying mechanism. Methods Mice received cecum ligation and puncture(CLP) to induce sepsis-associated acute liver injury. Male C57BL/6 mice were randomly (random number) divided into 3 groups (n=10 each group): (1) sham group (S group), (2) CLP group and (3) CLP +PDX group (PDX group ). Mice in the PDX group were received PDX 1 μg (intraperitoneal injection). One hour after CLP operation, mice in the S and CLP groups were received equal amounts of saline. The serum and liver tissues were collected at 24 h after CLP. The histological changes of the liver were observed by HE staining. The ALT and AST levels in the serum were assessed by using the automatic biochemical analyzer. The levels of cytokines (TNF-α, IL-6, IFN-γ and IL-10) in the serum were quantified by ELISA. MPO activity in the liver tissues were assessed. Western blot was used to detect the expression of pNF-kB p65 and NF-kB p65 in liver tissues. Results Compared with the S group, HE staining in the CLP group showed disordered hepatic cords, hepatocyte swelling and necrosis, infiltrations of inflammatory cells, congestion and bleeding, and the score of liver injury was increased significantly (P<0.05). Levels of ALT, AST, TNF-α, IL-6, IFN-γ, and IL-10 were increased in the CLP group (P<0.05). The activities of NF-κB and MPO in the liver tissues were obviously enhanced (P<0.05). The levels of liver injury, cytokines (TNF-α, IL-6, IFN-γ), MPO and activities of NF-κB in the CLP+PDX group were significantly decreased when compared with those in the CLP group (P<0.05),while the concentration of IL-10 was significantly increased (P<0.05). Conclusions PDX can alleviate sepsis-induced acute liver injury through inhibiting NF-KB activity in the liver tissues.

Objective To investigate the role of erlotinib in the expression of surfactant protein A (SP-A) in LPS-induced acute lung injury (ALI) of mice model.Methods C57BL/6 mice were randomly (random number)divided into control group (n=6),ER group (n=6),LPS group (n=6),and ER+LPS group (n=6).In the LPS group,2 mg/kg LPS was instilled into trachea of mice to induce lung injury.In control group,normal saline was instilled into trachea of mice instead.In the ER+LPS group and ER group,100 mg/kg of edotinib was instilled into stomach of mice,and one hour later.2 mg/kg LPS was instilled into trachea of mice in ER+PLS group to induce lung injury.Twenty-four hours later,bronchoalveolar lavage fluid (BALF) and lung tissue of mice in four groups were collected.HE staining were used for evaluating pathological changes of lung injury.Lung wet/dry weight ratio,protein concentrations and total cell numbers in the BALF were measured to determine the degree of pulmonary edema.Immunohistochemical staining and Western Blot were used for testing the protein expression of SP-A,Data of multiple groups were analyzed by one way variance (ANOVA) and inter-group comparisons were made by the least significant difference (LSD) tests.Results There was no significant difference in lung injury score (LIS) between control group (0.056±0.008) and ER (0.064±0.037) group,The LIS in LPS group (0.846-±0.047) was higher than that in control group,however the LIS in ER+LPS group (0.279±0.020) was significant lower than that in LPS group (P ＜ 0.05).Lung wet/dry weight,SP-A concentration and total cell numbers in the bronchoalveolar lavage fluid revealed that the degree of pulmonary edema in LPS group was higher than that in control group,and this pulmonary edema was reversed by erlotinib treatment.Immunohistochemical staining and Western blot showed that the expression of SP-A in LPS group was decreased compared with control group,but it was recovered after erlotinib treatment (P ＜ 0.05).Conclusions Erlotinib could protect the LPS-induced ALI,and it may be related to the regulation of SP-A.

Objective To evaluate the effect of resuscitation with Ringer′s malate solution on acute lung injury caused by hemorrhagic shock in rats. Methods Forty-eight SPF healthy male Sprague-Dawley rats, aged 7-9 weeks, weighing 280-320 g, were assigned into 4 groups ( n＝12 each) using a random number table method: sham operation group (group S), normal saline group (group NS), Ringer′s lac-tate solution group ( group RL) and Ringer′s malate solution group ( group RM). In NS, RL and RM groups, the model of hemorrhagic shock was established, and rats were resuscitated after 60 min of hemor-rhagic shock. Rats were sacrificed at 3 h after resuscitation, and bronchial alveolar lavage fluid ( BALF) was collected to count neutrophils. Lung tissues were obtained for determination of the wet∕dry weight ratio (W∕D ratio), myeloperoxidase (MPO) activity, and contents of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and IL-6. Lung tissues were obtained for examination of the pathological changes. Results Compared with group S, the neutrophil count in BALF, W∕D ratio, MPO activity and contents of TNF-α, IL-1β and IL-6 were significantly increased in NS, RL and RM groups ( P＜0. 05). Compared with NS and RL groups, the neutrophil count in BALF, W∕D ratio, MPO activity and contents of TNF-α, IL-1β and IL-6 were significantly decreased in NS and RL groups (P＜0. 05). Conclusion The severity of acute lung injury is reduced when Ringer′s malate solution is used for resuscitation as compared with that when normal saline and Ringer′s lactate solution are used in a rat model of hemorrhagic shock.

Objective To investigate the role of calcineurin(CaN)in inflammatory pain in rats.Methods Seventy-five male Harlan-Sprague-Dawley rats,weighting of 200-300 g were randomly divided into 3 groups (n=25): group control (group C),group CFA (complete Freunds adjuvant) (group F) and group CaN+CFA (group NF).100 μl CFA were injected on the right hind claw preparaing for inflammatory pain models in groups F and NF,100 μl saline were injected on the right hind claw in group C.CaN 10 U was intracerebroventricular injected 1 d before CFA injection in group NF.Paw withdrawal thermal latency (PWTL) were measured in 30 min prior to (T0),0.5 h (T1),1 h (T2),2 h (T3) and 4 h (T4) after injection.The expression of CaN and nuclear factor kappa B (NF-κB),IL-1β,TNF-α and IL-10 in spinal cord were measured at each time point.Results The PWTL was significantly shorter at T2-T4 in group F,at T3,T4 in group NF than that at T0and in group C (P<0.05);The PWTL at T2-T4 in group NF was significantly longer than that in group F (P<0.05).CaN protein expression in spinal cord at T1-T4 in group F,at T2-T4 in group NF was significantly lower than that of T0 and in the group C,NF-κB p65 protein expression was significantly higher than that of T0 and in the group C (P<0.05).CaN gene and IL-10 protein content at T2-T4 in groups F and NF were significantly lower than that of group C and at T0,NF-κB gene and IL-1β,TNF-α protein content was significantly higher than that of group C and at T0 (P<0.05).CaN protein and CaN gene expression,IL-10 protein content in spinal cord tissue at T1-T4in group NF was significantly higher than that of group F,NF-κB p65 protein and NF-κB gene expression and contents of IL-1β,TNF-α protein were significantly lower than that of group F (P<0.05).Conclusion CaN adjusts pro-inflammatory and anti-inflammatory cytokines by reducing NF-κB and inhibiting the process of inflammatory pain in rats.

Objective To compare the degree of liver injury during resuscitation with different crystalloid solutions in a rat model of hemorrhagic shock.Methods Forty-eight SPF healthy male SpragueDawley rats,aged 7-9 weeks,weighing 280-320 g,were assigned into 4 groups (n=12 each) using a random number table:sham operation group (group S),normal saline group (group NS),Ringer's lactate solution group (group RL) and Ringer's malate solution group (group RM).Hemorrhagic shock was induced by withdrawing blood from the right internal jugular vein until mean arterial pressure was reduced to 35-45 mmHg which was maintained for 1 h.The internal jugular vein and artery were cannulated after anesthetization,but no animals were subjected to hemorrhage in group S.The crystalloid solution (2 times the volume of blood loss) was infused intravenously over 30 min starting from 1 h of shock.The animals were resuscitated with 0.9％ sodium chloride solution in group NS,with Ringer's lactate solution in group RL,and with Ringer's malate solution in group RM.Mean arterial pressure was continuously monitored and recorded during the experiment.Before shock (T1),at 1 h of shock (T2) and at 4 h after resuscitation (T3),blood samples were collected from the right internal jugular vein for determination of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations by enzyme-linked immunosorbent assay.Rats were sacrificed at T3,and livers were removed for measurement of malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in liver tissues (using colorimetric method) and for examination of pathological changes of liver tissues (with light microscope).Results Compared with group S,the serum ALT and AST concentrations at T2.3 and SOD activity and MDA content at T3 were significantly increased in NS,RL and RM groups (P＜0.05).Compared with group NS or group RL,the serum ALT and AST concentrations were significantly decreased,the SOD activity was increased,and the MDA content was decreased at T3 (P＜0.05),and the pathological changes of liver tissues were significantly attenuated in group RM.Conclusion Ringer's malate solution produces better efficacy than normal saline and Ringer's lactate solution when used for resuscitation and mitigating liver injury in a rat model of hemorrhagic shock.

Objective To evaluate the role of spinal CX3C chemokine receptor 1 (CX3CR1) in inflammatory pain and the relationship with calmodulin (CaM)-calmodulin-dependent protein kinaseⅡ(CaMKⅡ) signaling pathways in mice.Methods Ninety-six pathogen-free healthy male C57BL6 mice,weighing 25-27 g,were divided into 3 groups using a random number table:control group (group C,n=30),inflammatory pain group (group IP,n=36) and CX3CR1 antagonist group (group CA,n=30).Inflammatory pain was induced by injecting complete Freund′s adjuvant (CFA) 50 μl into the plantar surface of right hind paws in IP and CA groups,while the equal volume of normal saline was given instead in group C.In group CA,CX3CR1 antagonist (diluted to 1 μg/5 μl in phosphate buffer solution) was intrathecally injected at 1 h before CFA injection.The thermal paw withdrawal latency (TWL) was measured at 30 min before CFA injection (T0) and 30 min,1 h,2 h and 4 h after CFA injection (T2-4).The animals were then sacrificed,and the spinal cord was removed for determination of the expression of phosphorylated CaMKⅡ (p-CaMKⅡ),phosphorylated cyclic adenosine monophosphate response element-binding protein (p-CREB) and c-fos (by Western blot) and expression of CaMKⅡ,CREB and c-fos mRNA (using real-time polymerase chain reaction).Immunofluorescence was used to determine that p-CAMKⅡ was expressed in microglia.Results Compared with group C,the TWL was significantly shortened at T2-4,and the expression of p-CaMKⅡ,p-CREB and c-fos protein and mRNA was up-regulated at T1-4 in IP and CA groups (P<0.05).Compared with group IP,the TWL was significantly prolonged at T2-4,and the expression of p-CaMKⅡ,p-CREB and c-fos protein and mRNA was down-regulated at T1-4 in group CA (P<0.05).p-CaMKⅡ was co-expressed with the microglial specific biomarker.Conclusion CX3CR1 is involved in the development and maintenance of inflammatory pain through activating CaM-CaMKⅡsignaling pathways in mice.