ABSTRACT
Objective:To investigate the mechanism of dexmetomidine (DEX) in improving lung injury in septic mice.Methods:Male C57BL/6 mice were randomly assigned to the blank group (NC), sham operation group (sham), cecal ligation and puncture group (CLP), and Dex treatment group (CLP+DEX), 36 mice per group. Mice in the CLP group were intraperitoneally injected with 1 mL sterile saline 15 min before CLP, and mice in the CLP + DEX group were intraperitoneally injected with 50 μg/kg DEX 15 min before CLP. The survival rate was recorded within 24 h after CLP. The mice were sacrificed at 0, 3, 6, 12, and 24 h after CLP, and lung tissues were collected. The expression levels of cytokines (IL-6, IL-1β, TNF-α) and lncRNA-HOTAIR in the lung of mice were detected by qPCR. RAW264.7 cell were cultured in vitro, LPS (100 ng/mL) and DEX (1 μ mol/L) were used to establish a cell model for studying the mechanism of Dex, and the expression of cytokines (IL-6, IL-1β, TNF-α) and lncRNA-HOTAIR in RAW264.7 cell model were detected by qPCR. In addition, the effect of lncRNA-HOTAIR on sepsis was explored in vivo and in vitro by knockdown or overexpression of HOTAIR.Results:The survival rate of the CLP+DEX group was higher than that of the CLP group within 24 h after surgery, and the levels of IL-6, IL-1β, and TNF-α in the lungs were significantly lower than those in the CLP group at 6, 12, and 24 h after surgery ( P<0.05). In addition, the level of lncRNA HOTAIR showed that the expression level of lncRNA HOTAIR in the lungs of mice were decreased after Dex treatment, and were decreased 1.1 times ( P<0.05), 4.0 times ( P<0.01) and 3.8 times ( P<0.01) at 6, 12, and 24 h, respectively. Compared with the NC group, knockdown of HOTAIR significantly decreased the levels of IL-1β, IL-6, and TNF-α in septic mice ( P<0.05), and overexpression of HOTAIR significantly increased the levels of IL-1β, IL-6, and TNF-α in septic mice ( P<0.01). Conclusions:DEX can reduce the production of inflammatory factors in the lungs of septic mice and improve the survival rate of septic mice. The mechanism may be related to the inhibition of HOTAIR expression.
ABSTRACT
Objective To explore the clinical value of early fluid resuscitation guided by passive leg-raising test (PLR) combined with transthoracic echocardiography (TTE) in patients with septic shock. Methods A prospective randomized controlled trial (RCT) was conducted. Seventy-four patients with septic shock admitted to China-Japan Friendship Hospital from January 2017 to October 2018 were enrolled. The patients were randomly divided into control group and experimental group with 37 patients in each group. Both groups of patients were treated with broad-spectrum antibiotics empirically, while received fluid resuscitation via the subclavian vein catheter. The patients of control group were given rapid fluid replacement, and those of experimental group received fluid replacement according to result of PLR combined with TTE. The stroke volume (SV) was measured by TTE before and after PLR, volumetric response of patients was judged by stroke volume variation (SVV). If the SVV≥15%, it was considered that there was a volume responsiveness, and fluid loading was given. If SVV﹤15%, it was considered that there was no volume shortage, and the restrictive fluid replacement was given. The goal of fluid resuscitation in both groups were to simultaneously meet the central venous pressure (CVP) of 8-12 mmHg (1 mmHg = 0.133 kPa), mean arterial pressure (MAP) ≥65 mmHg, urine volume ≥ 0.5 mL·kg-1·h-1, and central venous blood oxygen saturation (ScvO2) ≥ 0.70 within 6 hours. Vasoactive drugs were used when the patients could not achieve the treatment goals. The MAP, lactic acid (Lac), oxygenation index (PaO2/FiO2) and ScvO2 of the patients were determined at 6 hours of treatment, and serum C-reactive protein (CRP) and chest CT were reviewed at 48 hours of treatment, and compared with those before treatment. The total hospital stay and the mortality were recorded. Results There was no significant difference in gender, age, body weight and etiological structure between the two groups, which indicated that the baseline data were generally balanced. There was no statistical difference in MAP, Lac, PaO2/FiO2, ScvO2 and CRP before infusion between the two groups. After 6 hours of treatment, the MAP, Lac, PaO2/FiO2 and ScvO2 of the two groups were all better than those before infusion. Except for the difference in MAP between the experimental group and the control group (mmHg: 78.76±5.22 vs. 76.35±6.66, P > 0.05), the other three parameters in the experimental group were significantly better than those in the control group [Lac (mmol/L): 2.52±1.15 vs. 3.89±1.42, PaO2/FiO2 (mmHg):338.14±27.47 vs. 303.35±22.52, ScvO2: 0.70±0.04 vs. 0.63±0.05, all P < 0.01]. After 48 hours of treatment, CRP levels of both groups were lower than those before infusion, and the experimental group was better than the control group (mg/L: 110.12±39.80 vs. 137.98±31.23, P < 0.01). Chest CT showed that the incidence of pulmonary edema in the experimental group was significantly lower than that in the control group [13.5% (5/37) vs. 37.8% (14/37), P < 0.01]. The hospital stay of the experimental group was shorter than that of the control group (days: 21.47±5.58 vs. 28.33±4.93, P < 0.01), but no significant difference in mortality was found between the two groups [18.9% (7/37) vs. 18.9% (7/37), P > 0.05]. Conclusion Compared with the traditional rapid fluid replacement, early fluid resuscitation treatment strategies guided by the PLR combined with TTE, could better improve perfusion and oxygenation level of tissues and organs, avoid pulmonary edema caused by rapid fluid replacement, shorten the hospital stay in patients with septic shock, but had no significant effect on hospital mortality.