| This study explored the pathological changes and mechanism of Janzhou Da’er Goat urea poisoning.It was divided into control group,5% urea group and 10% urea group.Methods such as biochemical indicators,tissue sections,special staining,transmission electron microscopy,qRT-PCR,immunohistochemistry,Western Blot and 16 S rRNA microbial sequencing were used.The main results were as follows:The clinical symptoms of 5% urea group and 10% urea group were teeth grinding and foaming at the mouth.The necropsy changes in the 5% urea group and the 10% urea group showed that the liver was enlarged and was yellowish;the lungs were enlarged and hemorrhage;the kidneys were enlarged;and the rumen wall became thin.The blood ammonia concentration,IFN-γ content,ALT,ALP,AST,TBA,UREA,CERA and UA content in the 5% urea group and 10% urea group were extremely significantly increased(P<0.01),and the Ig G content was extremely significantly reduced(P<0.01).The hepatocytes of the 5% urea group and the 10% urea group were vacuolar degeneration and necrosis;The renal tubular epithelial cells were necrotic;The lung epithelial cells were necrotic,and the alveolar cavity was filled with inflammatory cells and serous substances;The stratum corneum of the rumen papilla was fell off and the thickness of the muscle layer was decreased.The content of liver MDA in the 5% urea group and the 10% urea group increased significantly,and the content of GSH,SOD and GSH-PX decreased significantly(P<0.01).Both the 5% urea group and the 10% urea group had collagen fiber hyperplasia in the liver.The nuclei of hepatocytes in the 5% urea group were enlarged,cytoplasmic lysosomes were increased;In the 10% urea group,the nuclei of hepatocytes were pyknotic,the mitochondria was myelinated,and the endoplasmic reticulum was swollen.The mRNA expression of Caspase-6,Caspase-8,Bax,TNF-α,TRADD,and Caspase-3 genes in liver of 5% urea group and 10% urea group were significantly up-regulated(P<0.01),and Bcl-2 mRNA expression in the 5% urea group was up-regulated(P<0.05),and Bcl-2 mRNA expression in the 10% urea group was significantly down-regulated(P<0.01).The expression of Caspase-3 protein in5% urea group and 10% urea group were increased significantly(P<0.01).The content of kidney MDA in the 5% urea group and the 10% urea group increased significantly,and the content of GSH,SOD and GSH-PX decreased significantly(P<0.01).The kidney iron content of 5% urea group and 10% urea group were increased(P<0.01).Both the 5% urea group and the 10% urea group had collagen fiber hyperplasia in the kidney.The mitochondria in the tubular epithelial cells of the5% urea group was shranked and the electron density of the mitochondrial membrane was increased;in the 10% urea group,the nucleus of the tubular epithelial cells was shranked,mitochondria was swelled,and cristae was decreased.The mRNA expression of FTH1,VDAC3,P53,and NCOA4 in kidney of the 5% urea group and10% urea group was increased significantly(P<0.01);the mRNA expression of VDAC2,FTL,and NRF2 in the 5% urea group was increased significantly(P<0.01),while The mRNA expression of FTL and NRF2 in the 10% urea group was decreased(P<0.01).The mRNA and protein expression of GPX4 in the 5% urea group and 10%urea group were extremely significantly decreased(P<0.01).The lungs of 5% urea group and 10% urea group both had collagen fibrosis proliferation and hemosiderin production.The nuclei of alveolar epithelial cells in the5% urea group were constricted and the mitochondria swelled;the alveolar epithelial cells in the 10% urea group were necrotic and disintegrated.The expression of RIP3 and TNF-α mRNA in the lung of the 5% urea group and 10% urea group was increased significantly(P<0.01);the mRNA expression of c IAP2 and TRADD in the5% urea group was increased significantly(P<0.01),while the mRNA expression of TRADD and TRADD in the 10% urea group was significantly decreased(P<0.01);the mRNA content of NEMO and Caspase-8 in lung of the 5% urea group and 10% urea group was significantly decreased(P<0.01),and the mRNA expression of HMBG-1and HSP70 were significantly up-regulated(P<0.01);The expression of RIP3 protein in 5% urea group and 10% urea group were increased significantly(P<0.01).The length of the rumen papilla became shorter,and the thickness of the stratum corneum and muscle layer became thinner in the 5% urea group and the 10% urea group(P<0.05).16 S rRNA microbial sequencing obtained a total of 663,883 original fragments(Raw Tags)and 405,542 effective fragments(Effective Tags).The average fragment length was 371,and a total of 1654 OTUs were obtained.Urea reduced the abundance of rumen microbial species and the diversity of rumen microbial community,among which the abundance of rumen Prevotella ruminicola was decreased significantly(P<0.05). |
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