Objective To explore the effect of exercise under cold exposure on hepatic protein ki-nase B(AKT)/forkhead box O1(FoxO1)expression in obese rats.Methods Among rats successfully induced nutritional obesity by high-fat diet,forty were selected and randomly divided into a normal-temperature control group(NC,n=10),a normal-temperature exercise group(NE,n=10),a sus-tained-cold control group(SC,n=10),and a sustained-cold exercise group(SE,n=10).The normal temperature was kept at 25°C±1°C,while the low temperature remained at 4°C±1°C,with 50%to 60%relative humidity.The exercise protocol was every other day at a speed of 25 m/min for 2 sets of 30 min each,with an interval of 10 minutes.After 5 weeks,glucose and insulin tolerance were tested by oral glucose tolerance test(OGTT)and insulin tolerance test insulin tolerance test(ITT).Then,all rats were weighed and sacrificed,then taken blood from the abdominal aorta to sepa-rate serum,followed by detection of serum alanine aminotransferase(ALT)and aspartate aminotransfer-ase(AST)levels using fully automatic biochemical analyzer.Moreover,livers were weighed to calcu-late the liver index.Meanwhile,the mRNA expressions of hepatic AKT,FoxO1 and PEPCK were de-tected using RT-qPCR,while the protein expressions of AKT,phosphorylated protein kinase B(p-AKT),and FoxO1 in the liver were measured using Western blotting.Results(1)The average body weights of the NE,SC and SE groups were significantly lower than the NC group(P<0.01),with that of the SC and SE groups significantly lower than the NE group(P<0.01).(2)Compared with the NC group,the area under the OGTT curve of the SC group decreased(P<0.01).Moreover,the area under the ITT curve of the SE group was significantly lower than the other 3 groups(P<0.01,P<0.01,P<0.05),with that of the NE and SC groups significantly lower than the NC group(P<0.05,P<0.01).(3)The liver indices of the NE,SC and SE groups were all significantly lower than the NC group(P<0.01),while the serum ALT level of the NE group was significantly lower than the NC and SE groups(P<0.05),with that of the SC group significantly lower than the NC group(P<0.01).(4)Compared with the NC group,hepatic AKT mRNA expression increased significantly in the SE group(P<0.05),while the hepatic FoxO1 and PEPCK mRNA expression decreased significantly in the other three groups(P<0.01).(5)Compared with the NC group,the liver AKT protein phosphorylation levels were significantly higher in the other three groups(P<0.05,P<0.05,P<0.01),while the FoxO1 protein expression decreased significantly(P<0.05,P<0.01,P<0.01).(6)Body mass,liver FoxO1,PEPCK mRNA expression,AKT protein phosphorylation level and FoxO1 protein expression level of obese rats were affected by cold exposure,exercise and cold exposure+exercise,and the liver index and serum ALT level were done by exercise and cold exposure+exercise.However,the area un-der the ITT curve and liver AKT mRNA content were impacted by cold exposure and exercise,while that under the OGTT curve was influenced by cold exposure and cold exposure+exercise.Conclu-sion Exercise under cold exposure can activate hepatic AKT/FoxO1 signaling pathway,protect liver function,increase insulin sensitivity,and effectively improve glucose metabolism in obese rats.

Objective To explore the effect of exercise under cold exposure on hepatic protein ki-nase B(AKT)/forkhead box O1(FoxO1)expression in obese rats.Methods Among rats successfully induced nutritional obesity by high-fat diet,forty were selected and randomly divided into a normal-temperature control group(NC,n=10),a normal-temperature exercise group(NE,n=10),a sus-tained-cold control group(SC,n=10),and a sustained-cold exercise group(SE,n=10).The normal temperature was kept at 25°C±1°C,while the low temperature remained at 4°C±1°C,with 50%to 60%relative humidity.The exercise protocol was every other day at a speed of 25 m/min for 2 sets of 30 min each,with an interval of 10 minutes.After 5 weeks,glucose and insulin tolerance were tested by oral glucose tolerance test(OGTT)and insulin tolerance test insulin tolerance test(ITT).Then,all rats were weighed and sacrificed,then taken blood from the abdominal aorta to sepa-rate serum,followed by detection of serum alanine aminotransferase(ALT)and aspartate aminotransfer-ase(AST)levels using fully automatic biochemical analyzer.Moreover,livers were weighed to calcu-late the liver index.Meanwhile,the mRNA expressions of hepatic AKT,FoxO1 and PEPCK were de-tected using RT-qPCR,while the protein expressions of AKT,phosphorylated protein kinase B(p-AKT),and FoxO1 in the liver were measured using Western blotting.Results(1)The average body weights of the NE,SC and SE groups were significantly lower than the NC group(P<0.01),with that of the SC and SE groups significantly lower than the NE group(P<0.01).(2)Compared with the NC group,the area under the OGTT curve of the SC group decreased(P<0.01).Moreover,the area under the ITT curve of the SE group was significantly lower than the other 3 groups(P<0.01,P<0.01,P<0.05),with that of the NE and SC groups significantly lower than the NC group(P<0.05,P<0.01).(3)The liver indices of the NE,SC and SE groups were all significantly lower than the NC group(P<0.01),while the serum ALT level of the NE group was significantly lower than the NC and SE groups(P<0.05),with that of the SC group significantly lower than the NC group(P<0.01).(4)Compared with the NC group,hepatic AKT mRNA expression increased significantly in the SE group(P<0.05),while the hepatic FoxO1 and PEPCK mRNA expression decreased significantly in the other three groups(P<0.01).(5)Compared with the NC group,the liver AKT protein phosphorylation levels were significantly higher in the other three groups(P<0.05,P<0.05,P<0.01),while the FoxO1 protein expression decreased significantly(P<0.05,P<0.01,P<0.01).(6)Body mass,liver FoxO1,PEPCK mRNA expression,AKT protein phosphorylation level and FoxO1 protein expression level of obese rats were affected by cold exposure,exercise and cold exposure+exercise,and the liver index and serum ALT level were done by exercise and cold exposure+exercise.However,the area un-der the ITT curve and liver AKT mRNA content were impacted by cold exposure and exercise,while that under the OGTT curve was influenced by cold exposure and cold exposure+exercise.Conclu-sion Exercise under cold exposure can activate hepatic AKT/FoxO1 signaling pathway,protect liver function,increase insulin sensitivity,and effectively improve glucose metabolism in obese rats.