Effect and mechanism of amphiregulin on acute respiratory distress syndrome in mice / 中华危重病急救医学

OBJECTIVE@#To explore the protective effect of amphiregulin (Areg) on acute respiratory distress syndrome (ARDS) in mice and its underlying mechanism.@*METHODS@#(1) Male C57BL/6 mice aged 6-8 weeks were selected for animal experiments and divided into 3 groups (n = 10) according to the random number table method, which includes sham-operated group (Sham group), ARDS model group [ARDS model in mice was established by intratracheal instillation of lipopolysaccharide (LPS) 3 mg/kg] and ARDS+Areg intervention group [recombinant mice Areg (rmAreg) 5 μg was injected intraperitoneally 1 hour after LPS modeling]. The mice were sacrificed at 24 h after LPS injection lung histopathological changes were observed under hematoxylin-eosin (HE) staining and scored for lung injury; oxygenation index and wet/dry ratio of lung tissue were measured; the content of protein in bronchoalveolar lavage fluid (BALF) was detected by bicinchoninic acid (BCA) method, the level of inflammatory factors interleukins (IL-1β, IL-6) and tumor necrosis factor-α (TNF-α) in BALF were measured by enzyme-linked immunosorbent assay (ELISA). (2) Mice alveolar epithelial cell line MLE12 cells were obtained and cultured for experiment in vitro. Blank control group (Control group), LPS group (LPS 1 mg/L) and LPS+Areg group (rmAreg 50 μg/L was added 1 hour after LPS stimulation) were set. The cells and culture fluid were collected at 24 hours after LPS stimulation, and the apoptosis level of MLE12 cells was detected by flow cytometry; the activation level of phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) and the expressions of apoptosis-related proteins Bcl-2 and Bax in MLE12 cells were detected by Western blotting.@*RESULTS@#(1) Animal experiments: compared with the Sham group, the lung tissue structure of ARDS model group was destroyed, the lung injury score was significantly increased, the oxygenation index was significantly decreased, the wet/dry weight ratio of lung was significantly increased, and the levels of protein and inflammatory factors in BALF were significantly increased. Compared with ARDS model group, lung tissue structure damage was reduced, pulmonary interstitial congestion, edema and inflammatory cell infiltration were significantly reduced, and lung injury score was significantly decreased (scores: 0.467±0.031 vs. 0.690±0.034) in ARDS+Areg intervention group. In addition, oxygenation index in ARDS+Areg intervention group was significantly increased [mmHg (1 mmHg ≈ 0.133 kPa): 380.00±22.36 vs. 154.00±20.74]. Lung wet/dry weight ratio (5.40±0.26 vs. 6.63±0.25), protein and inflammatory factors levels in BALF [protein (g/L): 0.42±0.04 vs. 0.86±0.05, IL-1β (ng/L): 30.00±2.00 vs. 40.00±3.65, IL-6 (ng/L): 190.00±20.30 vs. 581.30±45.76, TNF-α (ng/L): 30.00±3.65 vs. 77.00±4.16], and the differences were statistically significant (all P < 0.01). (2) Cell experiments: compared with the Control group, the number of apoptotic MLE12 cells was significantly increased in the LPS group, and the levels of PI3K phosphorylation, anti-apoptotic gene Bcl-2 level and pro-apoptotic gene Bax level were increased in MLE12 cells. Compared with the LPS group, the number of apoptosis in MLE12 cells was significantly reduced in the LPS+Areg group after administration of rmAreg treatment [(17.51±2.12)% vs. (36.35±2.84)%], and the levels of PI3K/AKT phosphorylation and Bcl-2 expression in MLE12 cells were significantly increased (p-PI3K/PI3K: 2.400±0.200 vs. 0.550±0.066, p-AKT/AKT: 1.647±0.103 vs. 0.573±0.101, Bcl-2/GAPDH: 0.773±0.061 vs. 0.343±0.071), and Bax expression was significantly suppressed (Bax/GAPDH: 0.810±0.095 vs. 2.400±0.200). The differences were statistically significant (all P < 0.01).@*CONCLUSIONS@#Areg could alleviate ARDS in mice by inhibiting the apoptosis of alveolar epithelial cells through activating PI3K/AKT pathway.

Application progress of ultrasound monitoring of diaphragm function in clinic / 中华危重病急救医学

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.

Research progress on the mechanism of pro-inflammatory regression mediators promoting inflammation regression by regulating immune cells / 中华危重病急救医学

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.

The protective effect of Protectin DX on acute liver injury induced by sepsis in mice and the underlying mechanism / 中华急诊医学杂志

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.

Effects of rosiglitazone on ventilator-associated lung injury in mice / 中华麻醉学杂志

Objective To evaluate the effects of rosiglitazone on ventilator-associated lung injury (VALI) in mice.Methods Twenty-four healthy male C57 mice,weighing 20-25 g,aged 6-8 weeks,were randomly divided into 3 groups (n =8 each) using a random number table:sham operation group (group S);group VALI;rosiglitazone group (group RGZ).The mice only underwent tracheotomy in group S.In group VALI,the mice were ventilated (respiratory rate 80 breaths/min,duration 4 h,tidal volume 40 ml/kg,fraction of inspired oxygen 21％,inspiratory/expiratory ratio 1:2,PEEP 0).In group RGZ,30 mg/kg rosiglitazone was given orally at 30 min before ventilation,and the other treatments were similar to those previously described in group VALI.At the end of ventilation,the mice were sacrificed,and the left lung was lavaged,and the broncho-alveolar lavage fluid (BALF) was collected for determination of neutrophil count.The pulmonary specimens were collected from the upper lobe of right lungs for microscopic examination of the pathological changes which were scored.The pulmonary specimens were obtained from the middle lobe of right lungs for measurement of the contents of interleukin-lbeta (IL-1β),tumor necrosis factor-alpha (TNF-α),high mobility group box-1 (HMGB-1) and receptor for advanced glycation end-products (RAGE) by enzyme-linked immunosorbent assay.Results Compared with group S,the neutrophil counts in BALF,contents of IL-1β,TNF-α,HMGB1 and RAGE,and lung injury score were significantly increased in VALI group (P＜0.01),and no significant change was found in the parameters mentioned above in group RGZ (P＞0.05).Compared with group VALI,the neutrophil counts in BALF,contents of IL-1β,TNF-α,HMGB1 and RAGE,and lung injury score were significantly decreased in group RGZ (P＜0.01).Conclusion Rosiglitazone can mitigate VALI in mice.

Effect of exogenous protectin DX on acute lung injury in septic mice / 中华麻醉学杂志

Objective To investigate the effect of exogenous protectin DX (PDX) on acute lung injury in septic mice.Methods Thirty male C57BL/6 mice,aged 6-8 weeks,weighing 20-25 g,were randomly divided into 3 groups (n =10 each) using a random number table:sham operation group (Sham group),sepsis group (S group) and PDX group.Sepsis was produced by cecum ligation and puncture (CLP) in the mice anesthetized with pentobarbital sodium.At 1 h after CLP,PDX 300 ng was injected intraperitoneally in PDX group,and the equal volume of normal saline was given in Sham and S groups.At 24 h after CLP,the mice were sacrificed,and the broncho-alveolar lavage fluid (BALF) was collected for determination of interleukin-1beta (IL-1β),tumor necrosis factor-alpha (TNF-α),IL-6 and IL-10 concentrations,and the lungs were removed for microscopic examination and for determination of the myeloperoxidase (MPO) activity,wet/dry lung weight ratio (W/D ratio) and phosphorylation of nuclear factor-kappa B (NF-κB) p65.Lung injury scores were calculated.Results Compared with Sham group,the lung injury score,MPO activity,W/D ratio,phosphorylation of NF-κB p65,and concentrations of protein and inflammatory factors in BALF were significantly increased in S and PDX groups (P＜0.05).Compared with S group,the lung injury score,MPO activity,W/D ratio,phosphorylation of NF-κB p65,and concentrations of protein,IL-1β,TNF-α and IL-6 in BALF were significantly decreased,and the concentration of IL-10 in BALF was significantly increased in PDX group (P＜0.05).Conclusion Exogenous PDX can alleviate acute lung injury through inhibiting NF-κB activity in the lung tissues of septic mice.

Effect of sivelestat sodium on the prognosis of patients with acute lung injury and acute respiratory distress syndrome：a meta-analysis / 中华危重病急救医学

ObjectiveTo investigate the effect of sivelestat sodium on the prognosis in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS).Methods Databases including PubMed, EBSCO, Springer, Ovid, Wanfang data, CNKI and China Biology Medicine (CBM) were searched to identify randomized controlled trials (RCTs) regarding sivelestat sodium treatment for ALI/ARDS published from 1985 to December 2014. The patients in treatment group received intravenous infusion of sivelestat sodium, and those in control group received normal saline. The items for analysis were 28-day mortality, duration of mechanical ventilation, length of intensive care unit (ICU) stay, and oxygenation index on day 3. According to the evaluation method of Cochrane system, data extraction and quality assessment from the literature were carried out. Meta-analysis was performed using RevMan 5.3. The publication bias was analyzed with funnel plot.Results Five RCTs with a total of 780 participants were included, with 389 patients in sivelestat sodium group, and 391 in control group. Meta analysis showed: compared with control group, sivelestat sodium could not lower the 28-day mortality [odds ratio (OR) = 0.91, 95% confidence interval (95%CI) =0.66-1.26,P = 0.58], or shorten the duration of mechanical ventilation or length of ICU stay [duration of mechanical ventilation: mean difference (MD) = -0.02, 95%CI = -0.29 to 0.24,P = 0.87; length of ICU stay:MD = -9.63, 95%CI =-23.34 to 4.08,P = 0.17], but it could improve oxygenation index on day 3 (MD = 0.88, 95%CI = 0.39 to 1.36, P = 0.000 4). Heterogeneity was not significant for the main analysis and no publication bias was shown on funnel plot. Conclusion Sivelestat sodium gave rise to a better oxygenation on day 3, but did not change the length of mechanical ventilation and ICU stay, and it did not improve 28-day mortality in ALI and ARDS.