Response Mechanism Of Przewalski's Gazelle(Procapra Przewalskii) To Selenium Deprived Environment

Przewalski's gazelle?Procapra przewalskii?is a critically endangered ungulates animal species endemic to the Plateau of China.Its historical distribution was wide,occurring throughout the provinces or autonomous regions of Gansu,Inner Mongolia,Ningxia,Qinghai,Xinjiang and Tibet regions.Now,it is only distributed in the deserts around Qinghai Lake on the Tibetan plateau.Based on our previous studied of the soil and forage mineral elements in the Hudong-Ketou area of Qinghai Lake,and showed that there is a severe selenium?Se?deficient situation.However,no obvious pathological manifestations have been observed in the Przewalski's gazelle,which inhabits a Se-deficient environment.Therefore,it is necessary to explore the response mechanism of Przewalski's gazelle to Se-deprived environment and propose new countermeasures for the protection of Przewalski's gazelle,which is not only the necessity of theoretical research,but also has important guiding significance in protection of endangered wildlife.In this study,to investigate the response of the Przewalski's gazelle to Se-deprived habitat,the system of"soil-grass-Przewalski's gazelle"in the Hudong-ketu,Yuanzhe and Bird Island areas of the Qinghai Lake Basin were taken as the research objects.We determined mineral contents in soil,forage and animal tissue,and measured parameters of blood routine,serum biochemical,blood rheology and antioxidant ability in animals.Meanwhile,iTRAQ-based proteomics combined with bioinformatics were applied to explore the differential proteome expression characteristics in Se-deficient Przewalski's gazelle and finding biomarkers of response of Przewalski's gazelle to Se-deprived environment at the protein level,and explore the response mechanism of Przewalski's gazelle to Se-deprived environment.The main research results were as follows:?1?The mineral nutrient contents of the soil and mixed pasture have obvious seasonality in the study areas.The contents of water-soluble copper?Cu?and Se in soil in seedling stage and withering period were significantly higher than that in fast growth period,the mineral nutrient contents of the mixed pasture in seedling stage and withering period was significantly higher than that in fast growth period,but there is no significant difference between seedling stage and withering period for pasture.Regardless of seedling stage,fast growth period or withering period,contents of selenium in mixed forage,and total and water-soluble selenium in soil in the Hudong-Ketu and Yuanzhe areas were significantly lower than those in Bird Island area and reference values.Thus,the Hudong-Ketu and Yuanzhe areas are both severely Se-deficient areas.?2?The Se deprivation in natural habitats severely disrupted the mineral nutrient metabolism,serum biochemical parameters and antioxidant system ability of Przewalski's gazelle in Hudong-Ketu and Yuanzhe areas.Specifically,Se contents in the blood and hair from the Przewalski's gazelle of the Hudong-Ketu and Yuanzhe areas were extremely significantly lower than those of the Bird Island and reference values.Contents of Cu,zinc?Zn?and manganese?Mn?in the blood from the Przewalski's gazelle of the Hudong-Ketu and Yuanzhe areas were extremely significantly higher than those of the Bird Island.Compared to the Przewalski's gazelle from Bird Island,serum levels of lactate dehydrogenase?LDH?,alkaline phosphatase?ALP?,creatine kinase?CK?,cholinesterase?CHE?were greatly significantly higher in the Hudong-Ketu and Yuanzhe group.Serum levels of thioredoxin reductase?TRXR?,superoxide dismutase?SOD?,glutathione peroxidase?GSH-Px?,catalase?CAT?and total antioxidant capacity?T-AOC?extremely significantly decreased,and serum malondialdehyde?MDA?,hydrogen peroxide?H₂O₂?,total nitric oxide synthase?T-NOS?,lipid peroxide?LPO?levels significantly higher in the Hudong-Ketu and Yuanzhe group.?3?The Se-deprivation in habitats marked impact on the blood routine and hemorheological parameters of Przewalski's gazelle in Hudong-Ketu and Yuanzhe areas.the values of red blood cell count?RBC?,hemoglobin concentration?HGB?,packed cell volume?PCV?and platelet count?PLT?were extremely significantly lower in the Hudong-Ketu and Yuanzhe group than the Bird Island group,the Hudong-Ketu and Yuanzhe group had significantly higher values than those of the Bird Island group at whole-blood shear rates??b?of 5s^-1and 1s^-1,and plasma viscosity??p?of 200 s^-1.the Hudong-Ketu and Yuanzhe group had significantly higher values than those of the Bird Island group at whole-blood reduced viscosity??re?,whole-blood reduced viscosity??re?,whole-blood relative viscosity,whole-blood relative viscosity,erythrocyte rigidity index,erythrocyte aggregation index,red blood cell deformability index.?4?In this study,the isobaric tag for relative and absolute quantification?iTRAQ?technology was first used to comprehensively analyze blood protein changes in the Przewalski's gazelle under Se-deficient conditions,A total of 130 differential proteins were identified compared with the non-selenium-deficient group,including 70 up regulated and 60down regulated proteins.27 proteins were further extracted because they evidently play important roles in multiple Se-associated biological processes,such as the oxidation-reduction process,immune response,Se binding,bone morphogenesis,endothelial development,and the regulation of growth.The Gene Ontology?GO?annotation showed,these altered proteins mainly corresponded to 1996 biological process,including single-organism,metabolic process,cellular process,biological regulation etc.,and annotated into 292 cell component,i.e.,extracellular region,biofilm,organelle etc.,also annotated into 303 molecular function,i.e.,binding,catalytic activity,molecular function regulator,structural molecule activity etc.KEGG pathway-based analysis showed that these differential proteins were mainly enriched into complement and coagulation cascades,focal adhesion,metabolic pathways,pancreatic secretion,platelet activation,oxidative phosphorylation etc.Protein-protein interaction?PPI?analysis presented that many important nodal proteins related to binding were found to be actively interacting with many different proteins,including ACTN1?alpha-actinin-1?,TUBA1B?tubulin alpha-1B chain?,HRG?histidine-rich glycoprotein precursor?,EEF1G?elongation factor 1-gamma?,and EEF1A1?elongation factor 1-alpha 1?etc.,and most of these proteins were involved in the regulation of a cellular biochemical process and/or closely associated with the regulation of signal transduction pathways.