[Study on serum metabolomics of combined injury induced by gas explosion in rats]

Objective: To analyze the changes of serum metabolomics in rats with combined injuries caused by gas explosion and explore its possible mechanism. Methods: In April 2018, the large coal mine gas explosion test roadway and explosion test system were used to simulate the gas explosion experiment. All 32 SD rats were randomly divided into four groups, control group (not involved in the explosion) , close range (40 m) group, medium range (160 m) group and long range (240 m) group, 8 in each group. The respiratory function at 2 hours and the neural behavior at 48 hours were detected after the explosion. The rats were anesthetized and sacrificed after 48 hours, and the serum, lung, liver and other tissues of the rats were isolated and histopathological changes of lung and liver tissues were observed by HE staining. Serum samples were detected by liquid chromatography-high resolution mass spectrometry (UPLC-Orbitrap Elite/MS) , and metabolic spectrum differences between groups were evaluated by principal component analysis. Differential metabolites were screened and identified, and metabolic pathways were analyzed. Results: Compared with control group, respiratory function indexes (respiratory frequency, minute ventilation, peak inspiratory flow rate, peak expiratory flow rate and 1/2 tidal volume expiratory flow) of rats in different explosion groups were significantly decreased (P<0.05) , but respiration pause, inspiratory time and 2/3 tidal volume required time were significantly increased (P<0.05) in 2 hours after the explosion. However, the residence times of the neurobehavioral indicators of the 40 m group and 160 m group were significantly increased (P<0.05) , and the movement distances were significantly decreased (P<0.05) in 48 hours after the explosion. HE staining results showed that the lung and liver tissues of the rats in the gas explosion group structurally damaged, and the cells were disordered, with inflammatory cell infiltration, bleeding and edema. Metabonomics analysis showed that there were significant differences in metabolic profiles between groups. A total of 18 differential metabolites were identified in serum samples, including aconitum acid, citric acid, niacinamide and pyruvate, which involved in 12 major metabolic pathways, including the glutamic acid and glutamine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, glyoxylic acid and dicarboxylic acid metabolism, phenylalanine metabolism, nicotinic acid and nicotinamide metabolism, citric acid cycle (TCA cycle) . Conclusion: Gas explosion can cause multi-organ system damage in rats, the mechanism of which may be related to the biosynthesis of alanine, tyrosine and tryptophan, metabolism of niacin and niacinamide, metabolism of acetaldehyde and dicarboxylic acid, and TCA cycle, etc.

Bioaccumulation of the rare earth elements lanthanum, gadolinium and yttrium in carp (Cyprinus carpio)

Widespread use of the rare earth elements (REEs) in China for agricultural purposes, together with many other applications, has resulted in a remarkable increase of REE concentrations in the environment. The comparative bioaccumulations of representative light, medium and heavy REEs in a variety of tissues of carp (Cyprinus carpio L.) were investigated for an evaluation of their impacts on aquatic animals. The fish were exposed continuously to solutions containing 0.50 mg litre(-1) of each element for 45 days at pH 6.0 and sacrificed at time intervals. Skeleton, muscle, gills and internal organs were analysed for REE contents. A method using cation-exchange resin separation and ICP-AES determination was developed for the quatification of individual REEs. The results show that carp has low ability to take up the REEs under the experimental conditions. The order of REEs under the experimental conditions. The order of maximum bioconcentration factors was mostly internal organs > gills > skeleton > muscle. Neither synergistic nor antagonistic effects of the mixed REE solutions for carp were observed. The relative distributions of different REEs in the investigated tissues exhibited similar patterns. Among the selected tissues studied, the concentration of a heavy REE (Y) was the smallest, while concentrations of a medium (Gd) and a light REE (La) showed only a slight difference.