Objective　To explore the effect of dexamethasone (Dex) given with the intention of prevention or treatment on endotoxin shock in rabbits and its relationship with tumor necrosis factor (TNF). Methods　Fifty-three health rabbits were divided into 4 groups, including normal control (n=13), endoxin shock group (n=16), preventive Dex group (n=12) and therapeutic Dex group (n=12). Except normal control was given with saline, the other 3 groups were administered with lipopolysaccharide (LPS) infusion, and the preventive Dex group was treated with Dex (5 mg/kg body weight) 30 min before LPS infusion and the therapeutic Dex group 20 min after LPS infusion. Mean arterial blood pressure (MABP), survival rate, TNF level in circulatory blood and other parameters were detected. Results　In preventive and therapeutic Dex groups, MABP was increased and survival rate was reduced compared with the animals from endoxin shock group (P<0.05, P<0.01), and TNF activity in the circulating blood was significantly suppressed (P<0.01). In addition, dexamethasone administration could alleviate the elevation of plasma glucagon, glucose, lactic acid, and β-glucironidase (P<0.05, P<0.01) in shocked animals. It was also found that administration of dexamethasone in vitro prevented the release of TNF by Kupffer cells. Conclusion　These results indicate that the preventive and therapeutic effect of dexamethasone on endotoxin shock, which may relate to its direct inhibition of the release of TNF induced by LPS.

BACKGROUNDPolymorphonuclear neutrophil (PMN), one of the most important inflammatory cells, functions throughout the initiation, progression and resolution of inflammation. This study aimed at investigating the relationship between PMN apoptosis and the lung injury after chest impact trauma.

METHODSPMNs were purified from rabbits subjected to the chest impact trauma and their apoptosis, necrosis, survival and respiratory burst were detected by flow cytometry. Meanwhile, lactate dehydrogenase and (LDH) [Ca2+]i were measured.

RESULTSThe delayed apoptosis of PMNs in bronchoalveolar lavage fluid was observed from 2 hours to 12 hours after trauma, and viable cells increased. Respiratory burst of PMNs in bronchoalveolar lavage fluid was increased significantly from 2 hours with the peak at 8 hours. Meanwhile, lactate dehydrogenase in bronchoalveolar lavage fluid was higher than that in control (P < 0.05) from 4 hours to 24 hours, and intracellular free Ca2+ in PMN was increased temporarily.

CONCLUSIONSRetention of PMN in tissues and the abnormality in apoptotic pathway inevitably generate persistent activation of PMN and excessive release of toxic substances, resulting in tissue injury. The temporary increase of intracellular free Ca2+ may be responsible for the delayed apoptosis of PMN.

Animals ; Apoptosis ; physiology ; Lung Injury ; Neutrophils ; physiology ; Rabbits ; Respiratory Burst ; physiology ; Thoracic Injuries ; complications

Objective: To explore the changes of γ-GCS mRNA expression and GSH-PX in serum of workers exposed to manganese in order to provide scientific basis for early diagnosis of manganese poisoning. Methods: In June 2017, a total of 180 workers from a motorcycle manufacturer were selected by stratified random sampling, including 115 welders as the exposure group and 65 administrative office workers as the Control Group, the exposure group was divided into high exposure group (43 persons) and low exposure group (72 persons) according to whether the exposure group exceeded the standard limit. The levels of γ-gcs Mrna expression and GSH-Px activity in serum were determined by Occupational Health Survey, and the differences of γ-gcs Mrna expression and GSH-Px activity among different groups were analyzed. Results: Compared with the control group, the serum GSH-Px activity was lower and the serum γ-GCS mRNA expression level was higher in the exposed group (F=370.52, 275.95, P<0.01) . Compared with the control group, there was significant difference in γ-GCS mRNA expression level and GSH-Px activity (F=0.475、1.06, P<0.01; F=48.53、111.70, P<0.01) . The concentrations of manganese in air, welding dust and urine were positively correlated with the level of γ-GCS mRNA (r=0.71, 0.50, 0.31, P<0.01) The serum GSH-Px activity was negatively correlated with the concentrations of manganese in air, welding dust and urine (r=-0.80, -0.52, -0.30, P< 0.01) , There was no correlation between Serum γ-GSH-Px activity and age and years of exposure (P>0.05) . Conclusion: Serum γ-GCS mRNA expression level and GSH-Px activity level can be used as early biomarkers of manganese poisoning. The concentrations of manganese in workplace air, welding dust and urine manganese in workers are the influencing factors.
Air Pollutants, Occupational ; Dust ; Humans ; Ions ; Manganese ; Manganese Poisoning ; Occupational Exposure/analysis* ; RNA, Messenger/genetics* ; Welding