Objective To analyze the relationship between intestinal flora and glucose metabolism changes in CG-IUGR rats by interventing CG-IUGR rats with the intestinal flora of normal rats.Methods SD rats were divided into three groups:the control group,the CG-IUGR group and the CG-IUGR+intestinal bacteria group(n=8 in each group).The CG-IUGR rat model was established by low-calorie diet.The intestinal flora of rats in the control group were transplanted into CG-IUGR rats in the CG-IUGR+intestinal bacteria group at 3-week-old(once a week,6 times in total).From birth to 8 weeks,the body weight and body length were measured in three groups of rats,and body mass index(BMI)was calculated.The relevant indexes of glucose metabolism were detected in three groups,including fasting blood glucose(FBG),serum fasting insulin(FINS)and serum insulin(INS)at 15 min after glucose loading and tolerance test of glucose and insulin.The mRNA and protein expression levels of skeletal muscle glycogen synthase(GYS)1 and liver GYS2 were detected by real-time fluorescence quantitative polymerase chain reaction(qPCR)and Western blot assay respectively.The activities of GYS in skeletal muscle and liver were detected.16S rDNA sequencing was used to detect the diversity and composition of intestinal flora in rats of three groups.Results Compared with the control group,the body length,body weight and BMI of rats in the CG-IUGR group were all increased significantly during the process of growth and development.Its serum FINS level decreased,and serum FBG had no significant change.The blood glucose levels of rats in the CG-IUGR group were significantly up-regulated after glucose and INS loading.The serum INS level of rats in the CG-IUGR group was significantly up-regulated at 15 min after glucose loading.The mRNA and protein expression levels of skeletal muscle GYS1 and liver GYS2 in rats of the CG-IUGR group were decreased,and the activity of GYS was also decreased(P＜0.05).These above changes of rats in the CG-IUGR+intestinal bacteria group were all improved(P＜0.05).Compared with the control group,ACE and Chao1 indices of intestinal bacteria in rats of the CG-IUGR group were lower(P＜0.05).Compared with the CG-IUGR group,the relative abundance of intestinal bifidobacterium in rats of the CG-IUGR+intestinal bacteria group was increased(P＜0.05).Conclusion IUGR can attenuate the glucose metabolism fuction of CG-IUGR rats by down-regulating the expression and activity of GYS in skeletal muscle and liver tissue.The abnormal glucose metabolism in CG-IUGR rats is related to changes of intestinal flora.