[Excess Oxygen Supply for Different Time Periods Affect Energy Metabolism in Rat Alveolar Epithelial Type â ¡ Cells].

Objective To observe the effect of excess oxygen supply for different time periods on the mitochondrial energy metabolism in alveolar epithelial type Ⅱ cells. Methods Rat RLE-6TN cells were assigned into a control group (21% O2 for 4 h) and excess oxygen supply groups (95% O2 for 1,2,3,and 4 h,res-pectively).The content of adenosine triphosphate (ATP),the activity of mitochondrial respiratory chain complex V,and the mitochondrial membrane potential were determined by luciferase assay,micro-assay,and fluorescent probe JC-1,respectively.Real-time fluorescence quantitative PCR was employed to determine the mRNA levels of NADH dehydrogenase subunit 1 (ND1),cytochrome b (Cytb),cytochrome C oxidase subunit I (COXI),and adenosine triphosphatase 6 (ATPase6) in the core subunits of mitochondrial respiratory chain complexes Ⅰ,Ⅲ,Ⅳ,and Ⅴ,respectively. Results Compared with the control group,excess oxygen supply for 1,2,3,and 4 h down-regulated the mRNA levels of ND1 (q=24.800,P<0.001;q=13.650,P<0.001;q=9.869,P<0.001;q=20.700,P<0.001),COXI (q=16.750,P<0.001;q=10.120,P<0.001;q=8.476,P<0.001;q=14.060,P<0.001),and ATPase6 (q=22.770,P<0.001;q=15.540,P<0.001;q=12.870,P<0.001;q=18.160,P<0.001).Moreover,excess oxygen supply for 1 h and 4 h decreased the ATPase activity (q=9.435,P<0.001;q=11.230,P<0.001) and ATP content (q=5.615,P=0.007;q=5.029,P=0.005).The excess oxygen supply for 2 h and 3 h did not cause significant changes in ATPase activity (q=0.156,P=0.914;q=3.197,P=0.116) and ATP content (q=0.859,P=0.557;q=1.273,P=0.652).There was no significant difference in mitochondrial membrane potential among the groups (F=0.303,P=0.869). Conclusion Short-term excess oxygen supply down-regulates the expression of the core subunits of mitochondrial respiratory chain complexes and reduces the activity of ATPase,leading to the energy metabolism disorder of alveolar epithelial type Ⅱ cells.

Comparison of different sedatives in children before general anaesthesia for selective surgery: A network meta-analysis.

WHAT IS KNOWN AND OBJECTIVE: It is estimated that 60% of children undergoing anaesthesia develop severe preoperative anxiety. The anxiety is associated with adverse reactions. Sedatives such as dexmedetomidine, midazolam, clonidine, ketamine, and melatonin can be used as premedication against preoperative anxiety. However, no consensus has been reached on the choice of pre-anaesthetic sedatives in children before selective surgery. Therefore, the current network meta-analysis (NMA) was carried out to evaluate different sedatives in children aged between 1 and 7 before general anaesthesia for selective surgery. METHODS: Randomized clinical trials (RCTs) were retrieved from Pubmed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science databases from inception to October 22, 2021. Primary outcomes showed satisfactory sedation at parent separation and also at induction or mask acceptance. Secondary outcomes were those related to added benefits and side effects. The present NMA was conducted using the R software. Results of the study were reported as Relative Risk (RR) or Mean Difference (MD) at a 95% credible intervals (CrIs). RESULTS AND DISCUSSION: A total of 48 trials were included in the present study. It was found that the effectiveness of dexmedetomidine, midazolam, clonidine, and ketamine were superior to that of placebo in satisfactory sedation at parent separation and induction or mask acceptance. There was no significant difference between melatonin and placebo in satisfactory sedation at induction or mask acceptance. Dexmedetomidine, ketamine, clonidine, and melatonin were superior to placebo in reducing emergence delirium (ED). In addition, midazolam prolonged the length of stay in the post anaesthesia care unit (PACU) as compared with placebo. Dexmedetomidine caused a significant reduction in systolic blood pressure (SBP) and heart rate (HR). Nevertheless, it was noted that the hemodynamic changes were roughly within safety limits. WHAT IS NEW AND CONCLUSION: It was evident that the studied drugs can provide effective sedation with exception of melatonin and placebo. However, it was found that midazolam, ketamine, and clonidine lead to several side effects. The findings of the present study supported that dexmedetomidine, especially intranasal administration, has potential in the optimal selection of the sedatives for premedication in children. This is because the drug has effective sedation, reduced incidence of ED, side effects, and onset time.