[Decreased insulin sensitivity in rat hepatocytes with intrauterine growth retardation and establishment of insulin resistance cell model in vitro].

OBJECTIVE

To explore the hepatocyte insulin sensitivity of intrauterine growth retardation (IUGR) rats and establish an insulin resistance cell model in vitro.

METHODS

An IUGR animal model was established by protein malnutrition during the mother pregnancy. On 60 d and 90 d after birth, the offspring rats were fasted for 12 hours and then their angular vein blood was collected to measure the fasting plasma glucose and fasting serum insulin level, then the insulin resistance index (HOMA-IR) and insulin sensitivity index (ISI) were calculated. The insulin sensitivity was evaluated by HOMA-IR and ISI. Primary hepatocytes from each group were respectively isolated by two-step perfusion with collagenase and were defined as normal hepatocytes group and IUGR hepatocytes group. The normal hepatocyte group was divided into two groups: control group and insulin induction group. Insulin induction group was established by primary cultures of normal hepatocyte incubated with varying dilutions of insulin. CCK-8 was used to detect the viability of the cultured hepatocytes. Glucose oxidase-peroxidase method kit was used to measure glucose consumption of the hepatocytes.

RESULTS

HOMA-IR was significantly higher in IUGR rats than in the normal rats at the age of 60 days (t=-17.02, P<0.05) and 90 days (t=-12.52, P<0.05). ISI was significantly lower than in the normal rats aged 60 days (t=5.61, P<0.05) and 90 days (t=12.42, P<0.05). There were no significant differences in hepatocyte viability among the control group, IUGR group and insulin induction group after incubation of 48 h on day 60 (F=1.34, P=0.29) and day 90 (F=0.22, P=0.81). The glucose consumption of the IUGR group and insulin induction group were significantly decreased compared with the control group on day 60 (F=9.28, P=0.002) and day 90 (F=56.60, P<0.001), while there was no significant difference between the IUGR group and insulin induction group (P=0.08, P=0.10).

CONCLUSION

The insulin sensitivity of hepatocytes of IUGR rats decreased from adolescence to adulthood. High-dilution insulin may induce insulin resistance cell model in vitro.