The Effects Of Trans Fatty Acids And Saturate Fatty Acid On Insulin Resistance Of Rats

Objective:The important pathophysiological foundation of type 2 diabetes is insulin resistance(IR).IR plays an important role in the development and progress of T2DM. Many studies have suggested that lifestyle is one of the pivitol factors.The using of TFA in food is getting more and more widespread.This study was designed to understand the effects and mechanism of TFA on insulin resistance of rats,comparing with the harm with SFA.Methods:Twenty four healthy Sprague-Dawley rats weighing 247±4.9g were divided into three groups randomly:eight for normal control group(NOR group) intragastric administration with normal sodium;eight for saturate fatty acid group (SFA group) intragastric administration with fat milk;eight for trans fatty acids group (TFA group) intragastric administration with oleomargarine.The rats were weighten every week,the dosage of administration was 1ml/100mg.OGTT was taken at the beginning of the eighth week and then ITT after three days.All of rats were killed at the end of eighth week.The fasting plasma glucose,insulu,free fatty acid and blood fat were assayed.Various IR index were calculated.Expression of PPAR-γin liver and GLUT4 in muscle were detected by RT-PCR.The statistical analysis of the data was done with the statistical package of SPSS 11.0.Result:By the end of the eighth week,the weight of all the three groups rats grow up, compared with the NOR group and TFA group,and the mean weight of SFA group were significantly increased(P＜0.01) than the other two groups;there were no significant difference between NOR group and TFA group(P＞0.05).Comparing with the NOR group,the FINS and HOMA-IR of both TFA group and SFA group were increased than the NOR group(P＜0.05),and the ISI and QUICKI significantly decreased(P＜0.01).The OGTT results showed that,the plasma glucose of the TFA group increased significantly comparing the NOR group at 30 minutes(P＜0.05);the plasma glucose of the TFA and SFA group significantly increased at 60 minutes and 120 minutes(P＜0.01)than the NOR group.Insulin were injected into abdominal cavity, the plasma glucose of the TFA and SFA group significantly increased compared the NOR group after 120 minutes(P＜0.01).The rats of the SFA group and TFA group developed insulin resistance.Compared with the NOR group,the FFA,TG,TC, LDL-c and LDL/HDL of the other group were increased(P＜0.05);the HDL-c of the TFA group were significantly decreased(P＜0.01) than the other two group.The HDL-c of the TFA group were decreased and LDL/HDL were significantly increased than that the group SFA(P＜0.01).SFA and TFA diet decreased the expression of PPAR-y than the NOR diet(P＜0.01),but the TFA group decreased more than the SFA group(P＜0.05).The mRNA expression of GLUT4 decreased significantly in the TFA and SFA group than that the group NOR(P＜0.01),and about the mRNA expression of PPAR-γ,the SFA group decreased more than the TEA group(P＜0.05).Conclusion:This study revealed that both high SFA and TFA diet can increase the fasting insulin level of rats,result in hyperinsulinemia and insulin resistance. Increasing serum FFA and blood fat level,down regulating the mRNA expression of PPAR-γand GLUT4 may be the important mechanism of IR.At present,we should pay more attention to the diet habit and avoid eating high TFA food.