Research Of White Adipose Tissue In Tupaia Belangeri Under Food Restriction And Refeeding

Requirement of food resources will change with their habitats changing in nature environment.Meanwhile,different animals had a series of survival mechanisms to adapt to complex and changing environments.Small mammals also had corresponding adaptation strategies to cope with the shortage of food resources.White adipose tissue?WAT?was a main energy storage organ,which is an important energy source for animals in the face of food resource shortage.The mitochondrial activity in WAT was relatively lower,and the uncoupling proteins in the inner membrane of mitochondria can hardly occur,but it can be browned by low temperature stimulation and hormone activation,thereby making uncoupling protein-1?UCP1?expression increased.At present,there were many reports about that the impact of cold exposure on thermogenesis of white adipose tissue of mammals,but there were few reports on the affect of food restriction.In the present study,we were using Tupaia belangeri as the research object,we continue to explore the changes of physiological indexes and heat production about WAT of T.belangeri in the condition of food restriction and refeeding from individual,tissue and molecular levels on the basis of our previous researches.The current study provides an important basis for the variable energy homeostasis mechanism of T.belangeri to adapt to wild food resources,which also lays a certain theoretical basis for the adaptation mechanism of physiology and ecology of small mammals.This dissertation systematically conducts research from the following four parts:1.Investigate of physiological indexes of T.belangeri under food restriction and refeedingBody mass,body fat mass,food intake,resting metabolic rate?RMR?,wet lung weight,wet weight of the small intestine,cecum,and stomach showed phenotypic plasticity under food restriction and refeeding in T.belangeri.During the 28-day food restriction,it found that body mass,food intake,and RMR of T.belangeri decreased compared with that of the control group.During the 28 days of refeeding,these three physiological indicators increased again,and eventually returned to the control group?P>0.05?.After 28 days of food restriction,masses of heart,liver,kidney and large intestine did not change significantly,but masses of the small intestine,cecum and stomach wet mass were up-regulated in the digestive tract.All the indicators of changes returned to the control level after 28 days of refeeding?P>0.05?.All of the results showed that the T.belangeri can adjust the basic physiological homeostasis mechanism to adapt to the changing natural environment of food resources.2.PET/CT scan and morphological study on WAT of T.belangeri under food restriction and refeeding?1?PET/CT scan of inguinal WAT:PET/CT scans of the inguinal adipose tissue of T.belangeri under food restriction and refeeding for investigate their physiological and metabolic activities in food resource shortage.The results showed that after 28days of food restriction,the average radiation value?SUV?of the¹⁸F-fluorodeoxyglucose(¹⁸F-FDG)in WAT absorbed by the T.belangeri significant decreased compared to that of the control group.The SUV value returned to the control group after 28 days of refeeding?P>0.05?.It is shows that T.belangeri could reduce the physiological and metabolic activities to cope with the shortage of food resources,and maintain the homeostasis of the body mass regulation.?2?Morphological study of WAT:The inguinal adipose tissue was mainly WAT,and the morphological changes were observed with hematoxylin and eosin stained sections?HE?.The results showed that the shape of adipose tissue after 28 days of diet was significantly reduced compared with the control group,but the color and intercellular space was not changing.But after 28 days of refeeding,its size and color returned to the control level.It showed that the T.belangeri can consume adipose tissue when the energy insufficient,shrink of fat cell is uniformly during the consumption process,but the number of cells remains unchanged.3.Flow analysis of WAT of T.belangeri under restriction and refeedingUsing UCP1 antibody and beige adipocyte-specific antibodies to label groin adipocytes for explore the effect of food restriction on browning of WAT in T.belangeri.The results showed that the positive expressions of UCP1 and CD137 in the groin adipose tissue were 30.14%and 14.45%after 28 days of laboratory acclimation,and the expression levels decreased to 13.01%and 4.35%.The positive expressions were 28.57%and 15.8%after 28 days of refeeding,respectively?P>0.05?.It is shown that T.belangeri can reduce energy consumption under restricted food conditions by reducing browning of WAT.4.Changes of PRDM16,BMP7,COX-2,PPAR,and PGC-1?genes expressions under food restriction and refeedingqRT-PCR was used to analyze the relative expression levels of PRDM16,BMP7,COX-2,PPAR?and PGC-1?genes related to browning of WAT during food restriction and refeeding.The results showed that the relative expression of COX-2and BMP7 genes decreased significantly after 28 days of food restriction compared with the control group?P<0.05?,while the relative expression of PRDM16,PPAR?and PGC-1?genes did not change significantly?P>0.05?.After 28 days of refeeding,the relative expression of COX-2 and BMP7 genes increased to the control group level?P>0.05?.It is shown that food restriction can inhibit the heat production activity of WAT in T.belangeri,and reduce unnecessary energy consumption.In conclusion,body mass,food intake and resting metabolic rate?RMR?decreased of T.belangeri,and increase the wet weights of the lungs,small intestine,cecum,and stomach increase,and reduce the positive expressions of UCP1 and CD137 in WAT.The relative expression levels of COX-2 and BMP7 decreased under food restriction,thus inhibiting the browning of WAT in T.belangeri.After refeeding,the above indexes were recovered to the control levels.The present study confirms that the physiological indicators of T.belangeri had phenotypic plasticity under food restriction and refeeding,and the thermogenic activity significant decreased under restricting food in T.belangeri,which provided a certain physiological basis for the energy homeostasis mechanism of T.belangeri to adapt to food resource shortages.