| Small mammals have a high ratio of surface area to volume,which leads to increased heat loss when exposed to low temperatures.A variety of adaptive mechanisms have been formed through adaptive evolution,including huddling.Huddling is a strategy chosen by a variety of small mammalian animals to survive in a cold environment when people or animals(usually because of cold or fear)huddled together.The study of huddling is helpful to reveal the effects of huddling on energy metabolism in small mammals and to provide a reference for understanding its physiological and ecological significance.Brandt's vole(Lasiopodomys brandtii),a genus of rodent hamster squirrels,is a nonhibernating camp living social animal whose habitat is mostly extreme continental climates,and has long and cold winters.Brandt's voles live in groups,and are small in size,easy to catch and easy to raise,is the ideal animal material for the study of huddling.As one of the most active and important thermogenesis organs in animals,the liver is of great importance in energy metabolic.Based on the above,to explore whether the liver energy supply capacity and energy supply mode of the huddled Brandt's voles in the low-temperature environment has changed,the Brandt's voles were divided into the normal temperature control group(CON),the cold huddling group(CH),and the cold separate group(CS).We monitor the morphological and physiological indicators(weight,organ coefficient,resting metabolic rates,food intake),and western blotting was used to quantify the protein of the indexes that affect the number and function of liver mitochondria(mitochondrial fission)liver glycogen synthesis and decomposition,and liver fat synthesis and decomposition.The content of liver glycogen and triglycerides was detected through the kit,and the liver fat content was observed and quantified by oil red staining.The results are mainly obtained as follows:1.We analyzed the bodyweight of Brandt's vole in 8 weeks.The results showed that the bodyweight in the CON group had no significant difference between before and after treatment(P > 0.05),while the bodyweight of Brandt's voles in the CH group significantly decreased by16%.The weight in the CS group also significantly decreased by 12%.After low-temperature treatment,there was no significant difference in body weight between the CH group and the CS group(P > 0.05).2.By analyzing the organ coefficients of the liver,the results showed that there was no significant difference in organ coefficient liver between CON group,CH group and CS group(P > 0.05).3.By analyzing the resting metabolic rate,the results showed that there was no significant difference between CON group and CH group,but Brandt's vole in CS group was significantly higher than CON group and CH group(P < 0.05).4.By analyzing the food intake,the results showed that the food intake of CON group at normal temperature was maintained between 2.95 ± 0.15 g/day and 3.23 ± 0.20 g/day.From the second week to the end of the eighth week,CS group was significantly higher than CON group(P < 0.01).In the 6th week,CH group was significantly higher than CON group(P < 0.05).In the 2nd,4th and 6th week,CH group was significantly lower than CS group(P < 0.05).The food intake coefficient of CON group was significantly lower than that of CS and CH group(P <0.05).5.The contents of glycogen and triglyceride(TG)were detected by the detection kit,and the results were analyzed:(1)The content of glycogen in CS group was significantly lower than that in CH group and CON group(P < 0.05)and CH group was significantly lower than that in CON group(P < 0.05).(2)TG content in CS group was significantly lower than that in CON group and CH group(P < 0.05)and CH group was significantly lower than that in CON group(P< 0.05).The results of oil red staining on frozen sections of the liver showed that the immediate oxygen demand(IOD)of CS group was significantly lower than that of CH group and CON group(P < 0.05).6.The target molecules were quantified by western blotting,and the results are as follows.(1)The protein expression of DRP1 in CS group was significantly lower than that in CON group(P < 0.05).The protein expression of MFF of CH group and CS group was significantly lower than that of CON group(P < 0.05).The protein expression of FIS1 of CON group was significantly higher than that of CH group and CS group(P < 0.05).Compared with CON group,the protein expression of citrate synthase in CH group and CS group was higher(P < 0.05).(2)The protein expression of PYGL fluctuated significantly among different groups.CS group is significantly higher than CH group(P < 0.05),CS group is extremely significantly higher than CON group(P < 0.01),and CH group is significantly higher than CON group(P < 0.05).The protein expression of GS in CS group is significantly higher than CH group(P < 0.05)and CH group is significantly higher than CON group(P < 0.05).(3)The protein expression of FASN in CS group was significantly lower than that in CON group and CH group(P < 0.05).The expression of ACC protein in CS group was significantly lower than that in CH group and CON group(P < 0.05).These results suggest that low temperature induced body weight and liver weight decrease,food intake increase.In a cold environment,the level of mitochondrial division related enzymes was reduced.Citrate synthase level were raised.The up-regulation of glycogenolysis enzyme level enhances the decomposition ability and leads to the decrease of glycogen content.The down-regulation of liposynthetase level leads to a decrease in the ability of fat synthesis and a decrease in fat content in Brandt's voles.Huddling reduces the amount of oxygen needed to sustain essential metabolic activities of life.Through huddling,by upregulating PYGL,the decomposition of liver glycogen was alleviated;By up regulating FASN and ACC,the decrease of fat synthesis ability was alleviated. |
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