Study On The Identification And Distribution Of Brown Adipose Tissue In Sonid Sheep

Mammalian adipose tissue is divided into white adipose tissue,brown adipose tissue and beige.The main function of white adipocytes is to store energy.The structure and function of brown adipocytes are different from white adipocytes.Brown adipose tissue is mainly distributed in young mammals.It is the main tissue of non shivering thermogenesis in mammal,and also participates in the regulation of energy balance.Uncoupling protein 1(UCP1)on the inner mitochondrial membrane mediates the thermogenesis.In order to research the mechanism of brown adipose tissue in cold tolerance and lean mutton sheep breeding,we explored the distribution of brown adipocytes in Sonid sheep from the phenotype phenotype,cell morphology,cell ultrastructure,gene and protein level.The results are as follows: 1.Brown adipocytes with small lipid droplets were observed in perirenal,cervical and pericardial fat by H&E staining,and the number of brown adipocytes decreased at 30 days.There were brown adipocytes in the adipose tissue of the cervical only at 1 day after birth.The number of brown adipocytes in inguinal adipose tissue decreased with age.No brown adipocytes were observed in the adipose tissue of the tail and sternal.2.Transmission electron microscopy showed that there were brown adipocytes around perirenal,cervical and inguinal on day 1 and 7,and there were more mitochondria with cristae in the cells.Mitochondria were hardly observed in tail adipocytes.3.The expression of UCP1 protein was detected by immunohistochemistry.The expression of UCP1 protein was found in the adipose tissue around perirenal,cervical and inguinal on the 1st and 7th day after birth.Only a small amount of UCP1 protein was expressed in the adipose tissue around perirenal on the 30 th day after birth,but no UCP1 protein was detected in the tail fat.4.The expression of Ucp1 gene in perirenal,cervical and pericardial adipose tissue was detected by q-PCR.The expression of Ucp1 gene was higher on the 1st and 7th day of birth,and decreased significantly on the 30 th day.The expression of Ucp1 in dorsal adipose tissue was only detected on day 1,but decreased significantly on day 7in inguinal adipose tissue,but not on day 30.No expression of Ucp1 gene was detected in tail and sternal adipose tissue.5.The expression of UCP1 protein in perirenal,cervical and pericardial adipose tissue was higher at 1 d and 7 d after birth,and decreased at 30 d after birth by Western blot.UCP1 expression was found only in the adipose tissue of the cervical at day 1,but decreased significantly in the adipose tissue of the inguinal at day 7 and no expression at day 30.No UCP1 protein expression was detected in the adipose tissue of the tail and sternal at all stages.6.In addition,574 differentially expressed genes were selected by transcriptome sequencing of perirenal adipose tissue in Sonid sheep on day 1,7 and 30 after birth.Among them,353 differentially expressed genes were enriched into 279 KEGG pathways.There were 36 differentially expressed genes in each of fatty acid metabolism and thermogenesis.PSMB8 and CARM1 were related to adipocyte differentiation.In this study,we established a method for the identification of brown adipose tissue in mammals from the aspects of cell morphology,ultrastructure,gene expression and protein expression.H&E staining,q-PCR and western blot showed the same results.Transmission electron microscopy and immunohistochemistry showed the same results.The expression and distribution characteristics of brown fat in different parts of different days were found.Transcriptome sequencing was used to selected the differential genes of perirenal fat in lambs born in different periods,and partial differential genes and fat thermogenic genes were found.The distribution characteristics of brown adipocytes in Sonid sheep were summarized through the results of five methods.It provides a theoretical basis for the study of brown adipose tissue in ruminants.