| Testis,the main reproductive organ of male animals,has the function of producing male gametes and androgens.The changes of testis parameters and testicular internal substances such as testosterone,fatty acids,amino acids and so on have a great influence on the fertility of ram.This study aim to explore the changes of testicular metabolites at different developmental stages and sizes and to identify the key metabolites using non-targeted metabolomics.The underlying mechanism affectd the testicular development of Hu sheep was preliminarily illuminated in this research.The result would provid further scientific support for improving the fertility of Hu sheep.Results of the study is shown as follow:（1）The left testis weight,left testis long diameter,left testis short diameter,left epididymal weight and sperm concentration were measured and strong positive correlations among these phenotypes were observed in 345 six month old Hu sheep（R >0.5）.And there was a strong positive correlation between diameters of seminiferous tubules and the left testis weight in 55 randomly selected Hu sheep（R > 0.9）.Sperm concentration in the large testis group（A group）was significantly higher than that in small testis group（B group）（P < 0.01）.（2）A tatol of 660 metabolites were detected,of which 270 differential metabolites between A vs C（3 month old）（187 down-regulated,83 up-regulated）,226 differential metabolites between B vs C（169 down-regulated,57 up-regulated）and 147 differential metabolites between A vs B（69 down-regulated,78 up-regulated）were tentatively identified.The 233 key differential metabolites were annotated using the KEGG database,and the KEGG pathway enrichment analysis shown that lipid metabolism,energy metabolism and protein metabolism.were main pathways The energy metabolism-related genes of GLUT8,LDH,CS,G6 PD,PDHA2,ADPGK,the,lipid metabolism-related genes ACSL1,CPT1,FABP3,etc.,the amino acid metabolismrelated genes of GLUD1 and the antioxidant-related genes of Cu Zn-SOD were significantly higher in the A group than those in the other groups（P < 0.05）.The enzyme activities capacity of testicular fatty acid synthase,citrate synthase,pyruvate dehydrogenase and lactate dehydrogenase and total antioxidantwere significantly higher in the A group than those in the B group（P < 0.01）（3）There was a positively correlation between testis weight and crude fat content in six month old Hu sheep（R > 0.3）.The content of crude fat and triglyceride in A group were significantly higher than those in B group（P < 0.05）.The fatty acid profile of testis vary with altered testicular weight.While the content of free fatty acid and saturated fatty acid in A group were significantly higher than those in B group（P <0.05）,on the contrary,the content of monounsaturated fatty acids,polyunsaturated fatty acids,expecially n-3 polyunsaturated fatty acids displayed the opposite results（P <0.05）.The expression of lipid pathway-related genes and lipid pathway-related proteins ELOVL2,FADS2 in group A were significantly higher than those in group B（P < 0.05）.The immunohistochemistry results indicated that ELOVL2 and FADS2 were mainly expressed in sertoli cells and leydig cells.（4）Cell viability were positively associated DHA concentrations when setoli cells were treated with different concentrations of DHA（0,2.5,5,10,20,50 μM）for 48 h,in which The highest cell viability was observed at 50 μM of DHA.While antioxidant ability,lipid deposition and gene expression of proliferation-associated gene PCNA and anti-apoptotic gene Bcl2 were significantly increased in setoli cell at 50 μM of DHA（P< 0.05）,on the contrary,the gene expression of pro-apoptotic gene BAX was significantly inhibited（P < 0.05）.In conclusion,energy metabolism,lipid metabolism,expecially fat deposition and fatty acid synthesis,protein metabolism and antioxidant capacity were significantly increased in the testis of big testis group,and fatty acid profile of testis vary with altered testicular weight.DHA,as the key metabolite,has the ability to promote cell proliferation. |
PDF Full Text Request