| Objective: To ivestigate the effect of curcumin on hepatic glucugeogenesis and discuss the relationship between Egr-1/C/EBPα signaling pathway and glucogeogenesis.Methods:1 Animal groups and the preparation of diabetes model: 50 healthy female rats(weighting 180±20g),10 rats were regarded as control group,and were fed with normal forage,the other 40 rats were regarded as model group and were fed with high fat and high sugar diet.After 6 weeks,the 40 rats were injected 1% STZ 30mg/kg by peritoneal to establish T2 DM model.The control group only received an injection of same amout of saline.The blood glucose was monitored for 4 weeks.The rats whose random gulcose over16.7mmol/L were regarded as diabetic rats.27 rats were sucessfully established into diabetic rats.They were randomly seperated into 4 groups:the diabetic group,the low dose curcumin group,the middle dose curcumin group and the high dose curcumin group.2 Drug intervention: the rats of low dose,middle dose and high dose curcumin group were given respectively 125mg/kg/d,250mg/kg/d,500mg/kg/d curcumin compouds by gavage,the diabetic group and control group rats were given such as the volume corn oil by gavage.3 The preparation of specimen and detection indexs:After gavaging 10 weeks every day,the postcava blood fasting for 10 hours were collected.the serum were obtained to test FBG and insulin.Then all the rats were killed,the livers were frozen quickly by liquid nitrogen.The contents of Egr-1,G-6-P,PEPCK mRNA in liver tissue were measured by Real Time-PCR.the expressions of Egr-1,G-6-P,PEPCK protein were determined by Western blot.The content of DNA expression of Egr-1/C/EBPα was measured by Chip.Thehepatic glycogen was tested by special kit.4 Statistical analysis:all the data was analysed by SPSS 13.0 software packet.The results of quantitative data were measured with mean±standard deviations(sx ?).Comparisons between groups were tested by One-Way ANOVA analysis,multiple comparisions were tested by LSD,SNK-q test.Statistically significant difference was set at P<0.05.Results:1 The changes of serum indexs and glycogen amount(Table 1,Fig.1)The levels of blood glucose,insulin,HbA1 c,insulin resistance index were higher in diabetic group than the control group.Compared to the diabetic group,the levels of glucose and HbA1 c in curcumin groups were lower(P<0.05).The best was the middle dose.The second was the high dose.(P<0.05).Compared to the diabetic group,the levels of the insulin resistance index in middle and high dose groups were lower.(P<0.05).The lowest level of insulin resistance index was the middle dose group(P<0.05).The second was the high dose group(P<0.05).There was no significant difference between low dose group and diabetic group(P>0.05).Compared to the control group,the amounts of hepatic glycogen were lower in the diabetic group(P<0.05).The amounts of hepatic glycogen in low,middle and high dose curcumin groups were higher than diabetic group.The best was the middle dose.Second was the high dose(P<0.05).2 The expression levels of Egr-1,G-6-P,PEPCK mRNA in different groups(Table 2,Fig.2)Compared to the control group,the expression levels of Egr-1,G-6-P,PEPCK mRNA were higher.The mRNA expression levels of G-6-P,PEPCK were lower in low,middle,high dose curcumin groups than diabetic group.The best was the middle dose group.3 The expression levels of Egr-1,G-6-P,PEPCK protein in different groups(Table 3,Fig.3-4)Compared to the control group,the levels of Egr-1,G-6-P and PEPCK protein expression were higher than diabetic group.The levels of Egr-1,PEPCK protein expression were lower in low,middle,high curcumin groups than diabetic group.The best was the middle dose.The second was the high dose.The protein expression levels of G-6-P were lower in middle and low curcumin groups than diabetic group.The best was the middle dose group.The second was the low dose.There was no significant difference between diabetic and high dose group.4 The DNA levels of Egr-1 combining with C/EBPα in different groups(Table 2,Fig.2)Compared to the control group,the DNA levels of Egr-1/C/EBPα was higher in diabetic group(P<0.05).The DNA levels in three curcumin groups was lower than diabetic group,the middle dose was the best,Second was the high dose group(P<0.05).Conclusions:1 The levels of blood sugar,HbA1 c,insulin resistance index can be reduced by curcumin.The best was the middle dose group.2 The levels of G-6-P,PEPCK protain and mRNA can be reduced by curcumin,so it can reduce the amounts of hepatic glucogen and regulating glycometabolism.3 The Egr-1/C/EBPα pathway probably participated in the hepatic glucogeogenesis process,it was related with curcumin. |
