Dynamic changes of insulin sensitivity in rats with fetal growth restriction
10.3760/cma.j.issn.1007-9408.2011.04.007
- VernacularTitle:胎儿生长受限大鼠胰岛素敏感性的动态变化
- Author:
Yuhong GUAN
;
Yan XING
;
Xinli WANG
;
Yunpu CUI
;
Tongyan HAN
;
Xiaomei TONG
;
Meihua PIAO
- Publication Type:Journal Article
- Keywords:
Fetal growth retardation;
Insulin resistance;
Rats
- From:
Chinese Journal of Perinatal Medicine
2011;14(4):221-226
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the regular pattern of dynamic changes of insulin sensitivity in fetal growth restriction (FGR) rats. Methods Twenty pregnant female rats were randomly divided into two groups as normal-protein group (NP) and low-protein group (LP), which respectively received normal protein diet (20% protein) and low protein diet (8% protein) during pregnancy. Weights of newborns were measured within 6 hours after birth, and the LP offspring whose birth weights were at least 2 standard deviations below the mean of NP offspring (≤2 standard deviations) were defined as FGR rats. At day 3, 7, 14, 30, 60 and 90 after birth, rats were fasted for 12 hours and then angular vein blood was collected to measure fasting plasma glucose (FPG) and fasting serum insulin (FINS) level. At 90 days of age, intraperitoneal glucose tolerance test (IPGTT)was performed; and blood triglyceride ( TG ), low-density lipoprotein cholesterol ( LDL-C ),high-density lipoprotein cholesterol (HDL-C) and glycosylated hemoglobin Alc (HbAlc) were measured. Insulin sensitivity was evaluated by FINS, insulin resistance index (HOMA-IR), insulin sensitivity index (ISI) and IPGTT. Results (1) Birth weights of LP offspring [(4. 92 ± 0. 36) g]were significantly lower than those of NP ones [(6. 43 ± 0. 59) g] (t = 14. 73, P＜0. 05). The incidence of FGR in LP was 88. 2% ; and for the male and female rats, the FGR rate was 94. 1% and 83. 1%, respectively. (2) FPG levels in the male FGR rats were significantly higher than in the NP from the age of 60 days [(9.38 ± 1.57) mmol/L vs (5. 58 ± 1.24) mmol/L] to 90 days [(8. 95 ±1.83) mmol/L vs (6. 21± 1.14) mmol/L] (t=-3. 291, P＜0. 05), while FPG levels in female FGR rats increased significantly only at 90 days of age [(9. 08±1.65) mmol/L vs (6.73±0. 67) mmol/L](t=-3. 226,P＜0. 05). FINS levels were significantly higher in FGR rats than in the NP from the age of 30 days (male FGR rats) or 60 days (female FGR rats) to 90 days (P＜0. 05, respectively).Similarly, HOMA-IR was significantly higher in FGR rats than in the NP at the age of 30 days (male FGR rats) or 60 days (female FGR rats) to 90 days (P＜0. 05, respectively). ISI in male FGR rats showed a reduction in comparison with the NP from the age of 30 to 90 days, while as to the female FGR rats it was significantly lower than in the NP only at 60 days of age and continued to 90 days (P＜0. 05, respectively). IPGTT showed that after injection of glucose, blood glucose at all four points (from 0 min to 120 min) in both male and female FGR rats were higher than that in the NP (P＜0. 05). (3) No significant difference was observed in TG, LDL-C and HDL-C at 90 days of age between the FGR rats and NP ones, while HbA1c in the male FGR rats was significantly higher than that in the NP [(7. 03±0. 54) % vs (4. 37±0. 64)%,t= -8. 028, P＜0. 05]. Conclusions FGR rats are able to maintain glucose balance and normal insulin levels during their earlier age, while insulin sensitivity decreased from adolescence to adulthood. The change of insulin sensitivity is different between male and female FGR rats, and male FGR rats are more likely to develop insulin resistance.
