RÉSUMÉ
Objective @#To investigate the protective effect of melatonin (MT) on formaldehyde (FA) inhalation-in- duced acute lung injury (ALI) in rats and its mechanism through the regulation of nuclear factor E2-related factor 2 (Nrf2) signaling pathway．@*Methods @#Fifty female Wistar rats were randomly divided into Control group ，FA group，FA + MT 5 mg / kg group，FA + MT 10 mg / kg group and FA + MT 20 mg / kg group，with 10 rats in each group．Except for the Control group，all other groups inhaled 3 mg / m3 FA daily for 21 d consecutively to construct the tainted model，and then treated with different MT doses for 14 d．The tainting was continued during the MT treatment．Hematoxylin-eosin (HE) staining was used to observe the histopathological changes in lung tissue，lung water content and lung coefficient were weighed and measured，glutathione ( GSH) ，superoxide dismutase (SOD) and 8-hydroxydeoxyguanosine ( 8-OHdG) levels were measured by absorbance photometric method ，and enzyme linked immunosorbent assay(ELISA) was used to measure the levels of tumor necrosis factor-alpha (TNF-α) ，in- terleukin (IL) -6，and IL-1 β concentrations，Western blot to detect the protein expression levels of Nrf2，heme ox- ygenase-1 (HO-1) ，nuclear factor-κB ( NF-κB) ，and phosphorylated nuclear factor-κB ( p-NF-κB) in lung tis- sues，and quantitative polymerase chain reaction(qPCR) to detect the Nrf2，HO-1，and Kelch-like ECH-associated protein 1 (Keap1) mRNA expression levels. @*Results @#Compared with the control group，lung injury was obvious in rats in the FA group ; lung tissue GSH and SOD levels were reduced ，and 8-OHdG levels were elevated ( P < 0. 05) ; alveolar lavage fluid TNF-α , IL-6，and IL-1 β levels were elevated (P＜0. 05) ; Nrf 2 and HO-1 protein expression levels were reduced in the lung tissue (P＜0. 05) ，and p-NF-κB protein expression levels were was ele- vated (P＜0. 05) ; the relative mRNA expression of Nrf2 and HO-1 in lung tissue was decreased，and the relative mRNA expression of Keap1 was elevated (P＜0. 05) ．Compared with the FA group，the lung injury of rats in the MT group was improved ; the levels of GSH and SOD in the lung tissue were increased (P＜0. 05) ，and the level of 8-OHdG was decreased (P＜0. 05) ; the levels of TNF-α , IL-6，and IL-1 β in the alveolar lavage fluid were de- creased (P＜0. 05) ; and the expression levels of the Nrf2 and HO-1 proteins in the lung tissue were increased (P ＜0. 05) ．p-NF-κB protein expression level was decreased (P ＜0. 05) ; the relative mRNA expression levels of Nrf2 and HO-1 in lung tissues were increased (P＜0. 05) ，and the relative mRNA expression level of Keap1 was decreased (P＜0. 05) in lung tissues，and all of them were in a dose-dependent manner． @*Conclusion @#MT can al- leviate oxidative stress and inflammatory responses and mitigate FA exposure-induced acute lung injury by regula- ting the Nrf2 / Keap1 / HO-1 signaling pathway.
RÉSUMÉ
Objective To observe the change of sinus heart rate turbulence (HRT) and its relation to left ventricular systolic function (LVSF) in patients with acute coronary syndrome (ACS). Methods The 103 ACS patients and 62 healthy subjects were enrolled in this study, all of them received 24-hour Holter monitor. And the values of turbulence onset (TO), turbulence slope (TS)and heart rate variability (HRV) SDNN were calculated according the Holter records. The clinical information, left ventricular ejection fraction (LVEF) and left ventricular end diastolic diameter (LVEDD) were recorded. Then the ACS patients were divided into acute myocardial infarction (AMI)group and unable angina pectoris (UAP) group according to the cardiac enzymes and electrocardiogram. Results The value of TO was significantly higher in ACS group than in control group [(0.17±1.40)％ vs. (- 0.26±0.99)％, P＜0.05], and TS was significantly lower in ACS group than in control group [R-R interval:(0.88±2.51) ms vs. (2.60±2.76) ms, P＜0.01].There were significant differences in TS, LVEF and LVEDD between AMI group and UAP group (all P＜0.01), but there were no differences in HRV and TO between the two groups. TS was positively correlated with LVEF (r=0.21, P＜0.05), while TO was negatively correlated with LVEF (r=-0.26, P＜0.05) by Spearman correlation analysis. Conclusions HRT is significantly blunted in ACS patients and can evaluate cardiac autonomic function. It may be as a predictor of LVSF in ACS patients.